317 results on '"Nayyar, S"'
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102. With or without you... forget Washington. Wall Street is reforming health care.
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Solomon J, Underwood A, and Nayyar S
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- 1994
103. Radionuclide cerebral angiography in diagnosis and evaluation of carotid- cavernous fistula
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Nayyar, S
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- 1974
104. PERSONNEL MONITORING SYSTEM FOR RADIATION ACCIDENTS.
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Nayyar, S
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- 1969
105. Cold Agglutinin Disease and COVID-19: A Scoping Review of Treatments and Outcomes.
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Musuuza JS, Kumar S, Posa DK, Hans A, Nayyar S, Christensen L, and Kamoga GR
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Background: Reports suggest that patients with both acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and cold agglutinin disease (CAD) may experience poorer survival when treated with rituximab. We conducted a scoping review to evaluate severe outcomes, including intensive care unit (ICU) admission and mortality, in coronavirus disease 2019 (COVID-19) patients with CAD on various treatments, including rituximab., Methods: This review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Extension for Scoping Reviews (PRISMA-ScR). Four literature databases were searched on December 19, 2023, for studies reporting lab-confirmed SARS-CoV-2 and CAD, excluding rheumatological conditions., Results: Of the 741 screened articles, 19 were included. Studies, predominantly case reports (17/19) or case series (2/19), were mainly from the USA (8/19) and India (3/19), with others across Europe and Asia. Among 23 patients (61% female, median age 61 years), 21/23 had a new CAD diagnosis; only two had pre-existing CAD. Overall, 74% recovered, 21% died, and outcomes for one were unreported. Nine (39%) were ICU-admitted. Of rituximab-treated patients (n = 4), 25% were ICU-admitted, none died. Non-rituximab treatments (n = 19) saw 42% ICU admissions and 26% mortality., Conclusions: This review found no increased risk of severe outcomes in CAD and COVID-19 patients treated with rituximab., Competing Interests: Investigators will receive only normal scholarly gains from taking part in this study. The authors declare no competing interests., (Copyright 2024, Musuuza et al.)
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- 2024
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106. Testosterone and Prolactin Perturbations Possibly Associated with Reduced Levels of β-Arrestin1 in Mononuclear Leukocytes of Women with Premenstrual Dysphoric Disorder.
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Nayyar S, Archibong A, and Nayyar T
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- Female, Humans, Leukocytes, Mononuclear metabolism, Prolactin, Testosterone, Depressive Disorder, Major, Premenstrual Dysphoric Disorder metabolism, Premenstrual Syndrome
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Previously, we reported that a reduction in β-Arrestin1 protein levels in peripheral blood mononuclear leukocytes (PBMC) significantly correlated with the severity of depression symptoms in women with premenstrual dysphoric disorder (PMDD). This study aimed to determine whether the reduced premenstrual β-Arrestin1 protein levels were associated with changes in the regulator for late luteal phase progesterone secretion. The study participants ( n = 25) were non-pregnant women between 18 and 42 years of age not taking any antidepressants or receiving therapy and experiencing the luteal phase of menstruation. ELISA determined the β-Arrestin1 protein in PBMC; testosterone and prolactin levels from the plasma were determined by radioimmunoassay. Reduced levels of β-Arrestin1 protein in women with Hamilton Rating Scale for Depression (HAM-D) scores above 19 were observed alongside significantly higher plasma testosterone and prolactin concentrations. Understanding the mechanism underlying the initiation of PMDD will allow for identification of a key perturbed metabolic enzyme that can serve as a target for drug development to ensure the alleviation of PMDD, which has been suggested earlier as a risk factor for developing major depressive disorders.
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- 2023
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107. Clinical Characterization and Outcomes of Culture- and Polymerase Chain Reaction-Negative Cases of Infectious Keratitis.
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Atta S, Singh RB, Samanthapudi K, Perera C, Omar M, Nayyar S, Kowalski RP, and Jhanji V
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Purpose: To examine the clinical presentation, management, and outcomes of culture and polymerase chain reaction (PCR) negative cases of infectious keratitis., Methods: In this retrospective case series, we evaluated the laboratory and medical records of culture- and PCR-negative cases (2016-2020) reported to a tertiary care center, which were presumed to be infectious keratitis on the basis of clinical history and presentation., Results: A total of 121 cases with culture-negative keratitis were included in this study. The mean age of the patients was 48.42 ± 1.89 years, and 53.72% were female. At presentation, the presumed etiology was viral in 38.01%, bacterial in 27.27%, fungal in 8.26%, Acanthamoeba in 6.61%, and unlisted in 28.92% of cases. The most common risk factors were a previous history of ocular surface diseases (96.69%) and contact lens use (37.19%). In total, 61.98% of the patients were already on antimicrobial medication at presentation. The initial management was altered in 79 cases (65.29%) during the treatment course. Average presenting and final (post-treatment) visual acuities (VA) were 0.98 ± 0.04 (LogMAR) and 0.42 ± 0.03 (LogMAR), respectively. A significantly higher frequency of patients with a final VA worse than 20/40 (Snellen) had worse VA at initial presentation ( p < 0.0001). A history of ocular surface disease, cold sores, and recurrent infection ( p < 0.05) were more commonly associated with a presumed diagnosis of viral keratitis. The patients with presumed bacterial etiology were younger and had a history of poor contact lens hygiene ( p < 0.05)., Conclusions: We observed a distinct difference in clinical features among patients with culture-negative and PCR-negative keratitis managed for presumed viral and bacterial infections. Although there was significant variability in presentation and management duration in this cohort, the visual outcomes were generally favorable.
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- 2023
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108. From Awareness to Action: A Review of Efforts to Reduce Disparities in Breast Cancer Screening.
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Nayyar S, Chakole S, Taksande AB, Prasad R, Munjewar PK, and Wanjari MB
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Breast cancer is a significant public health concern, and addressing disparities in breast cancer screening is crucial for improving early detection and reducing mortality rates. This review article examines efforts to bridge the gap between awareness and action in reducing disparities in breast cancer screening. A systematic approach was employed to gather relevant literature using various databases. The selected studies encompassed a range of interventions, including policy changes, community-based programs, culturally competent interventions, technological advancements, and patient navigation. The review highlights the importance of policies and legislation in improving access to screening services and the impact of community-based initiatives in addressing disparities. Culturally competent interventions, tailored messaging, and language support were found to be effective in improving screening rates among diverse populations. Technological advancements, such as telemedicine and mobile health applications, were identified as promising approaches to increase access to screening services. Patient navigation programs effectively addressed barriers to screening and improved screening rates. The review also discusses evaluating efforts, limitations, and the need for continuous improvement. Future directions and recommendations include addressing gaps in the existing literature, proposing research directions, and providing recommendations for policymakers, healthcare providers, and researchers. By implementing these recommendations and working collaboratively, we can strive for equitable access to breast cancer screening for all populations, ultimately leading to improved outcomes and reduced disparities., Competing Interests: The authors have declared that no competing interests exist., (Copyright © 2023, Nayyar et al.)
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- 2023
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109. Wave tail mapping to guide ablation therapy for ventricular arrhythmias.
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Anderson RD, Nayyar S, Masse S, Lambiase PD, and Nanthakumar K
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- Humans, Arrhythmias, Cardiac, Tachycardia, Ventricular, Catheter Ablation
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- 2023
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110. Intracardiac Electrogram Targets for Ventricular Tachycardia Ablation.
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Nayyar S
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- Humans, Electrophysiologic Techniques, Cardiac, Electrocardiography, Arrhythmias, Cardiac surgery, Catheter Ablation adverse effects, Tachycardia, Ventricular surgery, Tachycardia, Ventricular etiology
- Abstract
The pathogenesis of ventricular tachycardia (VT) in most patients with a prior myocardial scarring is reentry involving compartmentalized muscle fibers protected within the scar. Often the 12-lead ECG morphology of the VT itself is not available when treated with a defibrillator. Consequently, VT ablation takes on an interesting challenge of finding critical targets in sinus rhythm. High-density recordings are essential to evaluate a substrate based on whole electrogram voltage and activation delay, supplemented with substrate perturbation through alternate site pacing or introducing an extra stimulation. In this article, we discuss contemporary intracardiac electrogram targets for VT ablation, with explanation on each of their specific fundamental physiology., Competing Interests: Disclosure Dr S. Nayyar is examining voltage and time-domain mapping strategy for ventricular tachycardia ablation and is the principal investigator of Target- VT study (URL: www.ANZCTR.org.au. Unique identifier: ACTRN12620000049976). Dr S. Nayyar reports no relationships with industry. All figures included in this article are from Authors prior published and unpublished works., (Crown Copyright © 2022. Published by Elsevier Inc. All rights reserved.)
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- 2022
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111. Microsporidial Keratitis - First Case Series of a Rare Pathogen in the Wake of Flood Disasters of 2022 in Pakistan.
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Malik S, Ishaq M, Nayyar S, and Humayun S
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- Humans, Floods, Pakistan epidemiology, Water, Microsporidiosis diagnosis, Microsporidiosis drug therapy, Microsporidiosis microbiology, Eye Infections, Fungal diagnosis, Eye Infections, Fungal drug therapy, Keratitis diagnosis, Keratitis drug therapy, Keratoconjunctivitis diagnosis, Keratoconjunctivitis drug therapy, Keratoconjunctivitis epidemiology
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The recent monsoon rains in Pakistan were unprecedented and caused flooding all over Pakistan, especially in Sindh and Balochistan. Following this national disaster, various water-borne and contagious diseases started erupting all over the country. In such a calamity-struck city of Jacobabad, we started receiving cases with a peculiar set of ocular complaints mimicking viral keratoconjunctivitis. Failure to respond to traditional treatment and the unique appearance of these corneal opacities led to a rare diagnosis of Microsporidial Keratoconjunctivitis, which was later confirmed by microscopy and staining of corneal scrapings of the most affected case. In line with published literature, all cases were treated with topical fluoroquinolone and topical anti-fungal therapy, following which the disease was cleared within a week. The disease has seen an upward trend the world over, especially among Asia. To the best of our knowledge, no such cases have been reported in Pakistan as yet. In this case series, we highlight the strong correlation of emergence of microsporidial keratitis in patients following exposure to pooled water bodies after the monsoon rainy season and floods. Moreover, this report will help create awareness in eye professionals regarding the prevention, timely diagnosis and treatment of these rare and emerging cases. Key Words: Keratitis, Spores, Water-borne diseases, Microsporidia.
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- 2022
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112. Prophylactic anticoagulation in sinus rhythm for stroke prevention in cardiovascular disease: contemporary meta-analysis of large randomized trials.
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Lander K, Thakeria P, and Nayyar S
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- Administration, Oral, Aged, Anticoagulants, Humans, Middle Aged, Randomized Controlled Trials as Topic, Atrial Fibrillation complications, Atrial Fibrillation diagnosis, Atrial Fibrillation drug therapy, Cardiovascular Diseases complications, Stroke diagnosis, Stroke etiology, Stroke prevention & control
- Abstract
Aims: Anticoagulation with non-vitamin K oral anticoagulants (NOACs) to prevent stroke is a mainstay of atrial fibrillation (AF) management. However, multiple cardiovascular diseases (CVDs) are associated with elevated ischaemic stroke risk even in sinus rhythm. In this meta-analysis, we assess efficacy and safety of prophylactic NOAC agents for stroke prevention in patients without AF., Methods and Results: A search was conducted for randomized controlled trials (RCTs) that evaluated an NOAC and control drug (placebo or antiplatelet) in non-AF patients with mixed CVD. The primary efficacy and safety outcomes were ischaemic stroke and major bleeding, respectively. Results were stratified based on primary- and mini-NOAC doses. Thirteen RCTs were identified with a total of 89 383 patients with CVD in sinus rhythm (53 778 on NOAC, 35 605 on control drug; mean age 65.5 ± 2.7 years). Over a mean follow-up of 18.3 months, 1429 (1.6%) ischaemic strokes occurred. Use of NOAC was associated with 26% reduction in stroke [odds ratio (OR) 0.74, 95% confidence interval (CI) 0.62-0.87; 1.1 vs. 1.8 events per 100 person-years], with numbers needed to treat of 153 patients to prevent one stroke. Major bleeding was increased with NOAC (OR 1.74, 95% CI 1.44-2.09; 2.1 vs. 1.0 events per 100 person-years). The weighted net clinical benefit (wNCB, composite of ischaemic stroke and bleeding) did not suggest a favourable effect with any NOAC dose (wNCB for primary-dose: -0.35; mini-dose: -0.06)., Conclusion: Current evidence does not support use of NOACs for stroke prevention in non-AF CVD population as risk of major bleeding still exceeds ischaemic stroke benefit., (Published on behalf of the European Society of Cardiology. All rights reserved. © The Author(s) 2021. For permissions, please email: journals.permissions@oup.com.)
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- 2022
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113. Impact of moderate and severe primary open-angle glaucoma on quality of life due to activity limitation.
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Nayyar S, Kumar S, Rehman O, Ichhpujani P, and Singla E
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- Aged, Cross-Sectional Studies, Humans, Male, Middle Aged, Surveys and Questionnaires, Visual Acuity, Glaucoma, Open-Angle diagnosis, Quality of Life
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Purpose: To study the impact of moderate and severe primary open-angle glaucoma (POAG) on the quality of life (QoL) due to activity limitation using glaucoma-specific questionnaires., Methods: This cross-sectional study enrolled 122 participants, 50% (n = 61) being controls and 50% were diagnosed cases of moderate/severe POAG. Three orally administered glaucoma-specific QoL instruments were used: Glaucoma Activity Limitation (GAL-9), Glaucoma Quality of Life (GQL-15), and Viswanathan questionnaires. The questions related to activity limitation were identified and analyzed for each questionnaire separately., Results: The mean age of the participants was 61.04 ± 9.88 years and a majority were males (64.8%, n = 79). The mean scores in controls, moderate glaucoma, and severe POAG patients for GAL-9 questionnaire were 9.77 ± 1.36 (P = 0.44), 13.75 ± 4.76 (P < 0.001), and 23.45 ± 5.62 (P < 0.001), for GQL-15, these were 16.39 ± 2.18 (P = 0.5), 22.75 ± 7.89 (P < 0.001), and 39.34 ± 9.42 (P < 0.001), respectively, while for the Viswanathan questionnaire, they were 9.49 ± 0.94 (P = 0.38), 7.91 ± 1.59 (P < 0.001), and 4.41 ± 2.20 (P < 0.001), respectively. The GQL-15 and GAL-9 questionnaires concluded that activity limitation pertaining to dark adaptation-related tasks affected the QoL the most in moderate as well as severe POAG (P < 0.001). Using the Viswanathan questionnaire, it was observed that the peripheral vision-related activity limitation was most significant for the decrease in QoL in moderate POAG while near vision-related activity limitation affected the QoL the most in severe POAG (P < 0.001)., Conclusion: All three questionnaires concluded that the activity limitation due to moderate and severe glaucoma has a negative impact on the QoL. The limitation of the tasks involving dark adaptation/glare and peripheral vision has the most significant impact on the QoL in moderate glaucoma. As the disease progresses to a severe category, the limitation of activities requiring central and near vision causes the most significant worsening in QoL., Competing Interests: None
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- 2022
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114. The Role of Artificial Intelligence and Machine Learning in Clinical Cardiac Electrophysiology.
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Ng B, Nayyar S, and Chauhan VS
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- Humans, Algorithms, Artificial Intelligence, Automation methods, Cardiology, Cardiovascular Diseases diagnosis, Electrophysiologic Techniques, Cardiac methods, Machine Learning
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In recent years, numerous applications for artificial intelligence (AI) in cardiology have been found, due in part to large digitized data sets and the evolution of high-performance computing. In the discipline of cardiac electrophysiology (EP), a number of clinical, imaging, and electrical waveform data are considered in the diagnosis, prognostication, and management of arrhythmias, which lend themselves well to automation through AI. But equally relevant, AI offers a unique opportunity to discover novel EP concepts and improve clinical care through its inherent, hierarchical tenets of self-learning. In this review we focus on the application of AI in clinical EP and summarize state-of-the art, large, clinical studies in the following key domains: (1) electrocardiogram-based arrhythmia and disease classification; (2) atrial fibrillation source detection; (3) substrate and risk assessment for atrial fibrillation and ventricular tachyarrhythmias; and (4) predicting outcomes after cardiac resynchronization therapy. Many are small, single-centre, proof-of-concept investigations, but they still show ground-breaking performance of deep learning, a subdomain of AI, which surpasses traditional statistical analysis. Larger studies, for instance classifying arrhythmias from electrocardiogram recordings, have further provided external validation of their high accuracy. Ultimately, the performance of AI is dependent on the quality of the input data and the rigour of algorithm development. The field is still nascent and several barriers will need to be overcome, including prospective validation in large, well labelled data sets and more seamless information technology-based data collection/integration, before AI can be adopted into broader clinical EP practice. This review concludes with a discussion of these challenges and future work., (Copyright © 2021 Canadian Cardiovascular Society. Published by Elsevier Inc. All rights reserved.)
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- 2022
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115. Herpes Zoster Ophthalmicus After COVID-19 Vaccination: Chance Occurrence or More?
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Rehman O, Arya SK, Jha UP, Nayyar S, and Goel I
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- Acyclovir therapeutic use, Administration, Ophthalmic, Administration, Oral, Adult, Anti-Bacterial Agents therapeutic use, Antiviral Agents therapeutic use, Conjunctivitis, Viral diagnosis, Conjunctivitis, Viral drug therapy, Drug Therapy, Combination, Herpes Zoster Ophthalmicus diagnosis, Herpes Zoster Ophthalmicus drug therapy, Humans, Male, Moxifloxacin therapeutic use, SARS-CoV-2 immunology, Valacyclovir therapeutic use, Visual Acuity physiology, COVID-19 prevention & control, ChAdOx1 nCoV-19 adverse effects, Conjunctivitis, Viral etiology, Herpes Zoster Ophthalmicus etiology, Vaccination adverse effects
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Abstract: As the understanding of COVID-19 infection becomes better, it is being recognized as a complex multisystem pathology rather than just affecting the lungs. Several ocular findings have been documented by researchers in individuals infected with COVID-19, and ocular symptoms may even be the first presenting feature of COVID-19 infection in 2.26% individuals. Several countries have started vaccination with inactivated or live vaccines to combat this pandemic, and varied side effects have been reported after vaccination. Few cases of herpes zoster have previously been reported in elderly patients with comorbidities after receiving COVID-19 vaccines. In this article, the authors described 2 interesting cases of herpes zoster ophthalmicus (HZO) after receiving a live COVID-19 vaccine. The first case was a 35-year-old immunocompetent man who developed HZO 3 days postvaccine. The second case was a 40-year-old immunocompetent man who developed HZO 28 days postvaccine. To the best of our knowledge, no literature to date has described HZO after live vaccine., Competing Interests: The authors have no funding or conflicts of interest to disclose., (Copyright © 2021 Wolters Kluwer Health, Inc. All rights reserved.)
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- 2022
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116. RAM cannula with Cannulaide versus Hudson prongs for delivery of nasal continuous positive airway pressure in preterm infants: an RCT.
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Maram S, Murki S, Nayyar S, Kadam S, Oleti TP, Anne RP, Deshobhotla S, Sharma D, Arun S, and Vadije PR
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- Cannula, Female, Gestational Age, Humans, Incidence, Infant, Newborn, Infant, Premature, Male, Nose physiopathology, Respiration, Artificial instrumentation, Respiration, Artificial methods, Ventilator Weaning methods, Continuous Positive Airway Pressure instrumentation, Continuous Positive Airway Pressure methods, Respiratory Distress Syndrome, Newborn therapy
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Nasal continuous positive airway pressure (nCPAP) is the standard non-invasive respiratory support for newborns with respiratory distress. Nasal injury is a common problem with the interfaces used. To compare the incidence and severity of nasal injury in neonates with respiratory distress and supported on nCPAP with Hudson prong or RAM cannula with Cannulaide, a semipermeable membrane. This is an open-label, parallel-arm, gestational age-stratified, bi-centric, randomized control trial including neonates between 28 and 34 weeks gestational age and birth weight > 1000 g needing nCPAP. The size of the interface was chosen as per the manufacturer's recommendation. Of the 229 neonates enrolled, 112 were randomized to RAM cannula with Cannulaide and 117 to Hudson prong. The baseline characteristics were similar. Any nasal injury at CPAP removal was significantly lower in the RAM cannula with Cannulaide group [6 (5.4%) vs. 31 (26.4%); risk ratio-0.77 (95% CI 0.69-0.87); p = 0.0001]. The incidence of moderate to severe nasal injury, need for mechanical ventilation within 72 h of age, duration of oxygen, and requirement of nCPAP for > 3 days were similar. For preterm infants on nCPAP, RAM cannula with Cannulaide, compared to Hudson prongs, decreases nasal injury without increasing the need for mechanical ventilation.Trail registration: CTRI/2019/03/018333, http://www.ctri.nic.in ., (© 2021. The Author(s).)
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- 2021
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117. Multiform Ventricular Tachycardia With Conduction System Participation: Is There a Fourth-Limb of the His?
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Nayyar S
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- Humans, Heart Conduction System, Tachycardia, Ventricular diagnosis
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- 2021
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118. Safety, efficacy, and monitoring of bipolar radiofrequency ablation in beating myopathic human and healthy swine hearts.
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Bhaskaran A, Niri A, Azam MA, Nayyar S, Porta-Sánchez A, Massé S, Liang T, Veluppillai A, Du B, Lai PFH, Ha A, and Nanthakumar K
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- Animals, Arrhythmias, Cardiac physiopathology, Disease Models, Animal, Humans, Swine, Arrhythmias, Cardiac surgery, Heart Rate physiology, Heart Ventricles physiopathology, Monitoring, Physiologic methods, Radiofrequency Ablation methods
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Background: The safety and efficacy parameters for bipolar radiofrequency (RF) ablation are not well defined., Objective: The purpose of this study was to investigate the safe range of power, utility of transmyocardial bipolar electrogram (EGM) amplitude, and circuit impedance in ablation monitoring., Methods: Sixteen beating ex vivo human and swine hearts were studied in a Langendorff setup. Ninety-two bipolar ablations using two 4-mm irrigated catheters were performed at settings of 20-50 W, 60 seconds, and 30 mL/min irrigation in the left ventricle., Results: For low-power ablations (20 and 30 W), transmurality was observed in 29 of 38 (76%) and 10 of 28 (36%) ablations for tissue thickness ≤17 mm and >17 mm, respectively. For high-power ablations (40 and 50 W), transmurality was observed in 5 of 7 (71%) and 7 of 19 (37%) ablations for tissue thickness ≤17 mm and >17 mm, respectively. Steam pop occurrence for low- and high-power ablations was 11 of 66 (16%) and 16 of 26 (62%), respectively (P = .0001), respectively. Lesion depth (limited by transmurality) was 12.0 ± 5.7 mm and 12.3 ± 5.8 mm, respectively (P = 1). Transmyocardial EGM amplitude decrement >60% strongly predicted transmurality (area under the curve [AUC] 0.8), and circuit impedance decrement >26% predicted steam pops (AUC 0.75). Half-normal saline did not affect transmurality or incidence of steam pops compared to normal saline irrigation., Conclusion: Bipolar RF ablation at power of 20-30 W provided an ideal balance of safety and efficacy, whereas power ≥40 W should be used with caution due to the high incidence of steam pops. Lesion transmurality monitoring and steam pop avoidance were best achieved using transmyocardial bipolar EGM voltage and circuit impedance, respectively., (Copyright © 2021 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)
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- 2021
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119. An 18-Year Overview of Serratia marcescens Ocular Infection.
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Atta S, Perera C, Nayyar S, Kowalski RP, and Jhanji V
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- Aged, Anti-Bacterial Agents therapeutic use, Female, Humans, Male, Retrospective Studies, Risk Factors, Serratia marcescens, Endophthalmitis epidemiology, Endophthalmitis etiology, Endophthalmitis therapy, Eye Infections drug therapy, Eye Infections, Bacterial diagnosis, Eye Infections, Bacterial drug therapy, Eye Infections, Bacterial epidemiology
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Purpose: Serratia marcescens is a frequent ocular bacterial pathogen implicated in keratitis, endophthalmitis, and conjunctivitis. We evaluated the risk factors and treatment outcomes of ocular infections due to S. marcescens., Methods: In this retrospective observational study, all S. marcescens-positive cases between February 2002 and February 2020 were reviewed for ocular risk factors that included log of minimal angle of resolution visual acuity (VA), medical management, and time to epithelial defect closure., Results: Fifty-one patients were identified (72.5% females, 46.8±23.3 years). Forty-six patients had complete medical records, and 5 had microbiology data available. The most prevalent ocular risk factors were, contact lens (CL) use (68.6%), corneal disease (52.9%), and history of ocular surgery (41.2%). Mean presenting VA was 1.3±1.0. About half of the patients presented with a central ulcer (49%, 25), large infiltrate (20.4±31.8 mm2 mean), and hypopyon (43.1%, 22). All cases were reported to be susceptible to ciprofloxacin. Defect closure occurred in 52.3±117.1 days and final VA was 0.86±0.88. Adjunctive treatments were required in 14 cases (27.5%). One patient underwent surgical intervention. Features associated with poor VA outcomes included, history of glaucoma (P=0.038), older age at presentation (P<0.001), presence of hypopyon (0.045), poor VA at presentation (0.0086), time to epithelial defect closure (0.0196), and large infiltrate size (P=0.0345)., Conclusions: S. marcescens keratitis and conjunctivitis is associated with CL use and history of ocular surface disease. Worse outcomes were associated with older age, infiltrate size, presence of hypopyon, worse initial VA, longer time to epithelial defect closure, and history of glaucoma., Competing Interests: The authors have no funding or conflicts of interest to disclose., (Copyright © 2021 Contact Lens Association of Ophthalmologists.)
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- 2021
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120. Deep Learning Classification of Unipolar Electrograms in Human Atrial Fibrillation: Application in Focal Source Mapping.
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Liao S, Ragot D, Nayyar S, Suszko A, Zhang Z, Wang B, and Chauhan VS
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Focal sources are potential targets for atrial fibrillation (AF) catheter ablation, but they can be time-consuming and challenging to identify when unipolar electrograms (EGM) are numerous and complex. Our aim was to apply deep learning (DL) to raw unipolar EGMs in order to automate putative focal sources detection. We included 78 patients from the Focal Source and Trigger (FaST) randomized controlled trial that evaluated the efficacy of adjunctive FaST ablation compared to pulmonary vein isolation alone in reducing AF recurrence. FaST sites were identified based on manual classification of sustained periodic unipolar QS EGMs over 5-s. All periodic unipolar EGMs were divided into training ( n = 10,004) and testing cohorts ( n = 3,180). DL was developed using residual convolutional neural network to discriminate between FaST and non-FaST. A gradient-based method was applied to interpret the DL model. DL classified FaST with a receiver operator characteristic area under curve of 0.904 ± 0.010 (cross-validation) and 0.923 ± 0.003 (testing). At a prespecified sensitivity of 90%, the specificity and accuracy were 81.9 and 82.5%, respectively, in detecting FaST. DL had similar performance (sensitivity 78%, specificity 89%) to that of FaST re-classification by cardiologists (sensitivity 78%, specificity 79%). The gradient-based interpretation demonstrated accurate tracking of unipolar QS complexes by select DL convolutional layers. In conclusion, our novel DL model trained on raw unipolar EGMs allowed automated and accurate classification of FaST sites. Performance was similar to FaST re-classification by cardiologists. Future application of DL to classify FaST may improve the efficiency of real-time focal source detection for targeted AF ablation therapy., Competing Interests: VC is the author of FaST mapping intellectual property (US 10,111,598 B2) owned by University Health Network, Toronto, ON, Canada. The study sponsors were not responsible for machine learning/mapping algorithm development, data collection, analysis or the manuscript preparation. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Liao, Ragot, Nayyar, Suszko, Zhang, Wang and Chauhan.)
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- 2021
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121. Unusual case of intraocular medulloepithelioma in an adult male.
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Rehman O, Narang S, Nayyar S, and Aggarwal P
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- Adult, Child, Ciliary Body surgery, Eye Enucleation, Humans, Intraocular Pressure, Male, Neuroectodermal Tumors, Primitive diagnosis, Neuroectodermal Tumors, Primitive surgery, Uveal Neoplasms diagnosis, Uveal Neoplasms surgery
- Abstract
Medulloepithelioma is a rare tumor of the eye, arising from the posterior segment. This embryonic tumor is mostly seen in children and is very rare in adult population. This case report presents the case of a 39-year-old Indian male, who had gradual vision loss over 4 years in his left eye with new onset of pain. He was referred to our center in view of secondary cataract and intraocular mass. Vision in right eye was 20/ 20 while left eye had no light perception at presentation. Ocular examination of the left eye revealed shallow anterior chamber, florid iris neovascularization, raised intraocular pressure and cataractous lens. B-scan ultrasonography showed a heterogenous mass filling the entire globe. MRI scan confirmed the finding, showing a mass hyper-intense to vitreous. No invasion of optic nerve or sclera was observed. Left eye enucleation with PMMA implant placement was performed and histopathology confirmed the diagnosis of benign teratoid medulloepithelioma. At the time of submission of this report, the patient was still under follow-up and had no detectable metastases at 15 months follow-up. This report highlights a very rare case of embryonic tumor in adult male, which could be managed successfully with a high index of suspicion and timely intervention., (© The Authors.Romanian Society of Ophthalmology.)
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- 2021
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122. Unipolar electrogram-based voltage mapping with far-field cancellation to improve detection of abnormal atrial substrate during atrial fibrillation.
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Ragot D, Nayyar S, Massin SZ, Ha ACT, Singh SM, Labos C, Suszko A, Dalvi R, and Chauhan VS
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- Electrophysiologic Techniques, Cardiac, Heart Atria diagnostic imaging, Heart Atria surgery, Humans, Atrial Fibrillation diagnosis, Atrial Fibrillation surgery, Catheter Ablation, Pulmonary Veins surgery
- Abstract
Introduction: An important substrate for atrial fibrillation (AF) is fibrotic atrial myopathy. Identifying low voltage, myopathic regions during AF using traditional bipolar voltage mapping is limited by the directional dependency of wave propagation. Our objective was to evaluate directionally independent unipolar voltage mapping, but with far-field cancellation, to identify low-voltage regions during AF., Methods: In 12 patients undergoing pulmonary vein isolation for AF, high-resolution voltage mapping was performed in the left atrium during sinus rhythm and AF using a roving 20-pole circular catheter. Bipolar electrograms (EGMs) (Bi) < 0.5 mV in sinus rhythm identified low-voltage regions. During AF, bipolar voltage and unipolar voltage maps were created, the latter with (uni-res) and without (uni-orig) far-field cancellation using a novel, validated least-squares algorithm., Results: Uni-res voltage was ~25% lower than uni-orig for both low voltage and normal atrial regions. Far-field EGM had a dominant frequency (DF) of 4.5-6.0 Hz, and its removal resulted in a lower DF for uni-orig compared with uni-res (5.1 ± 1.5 vs. 4.8 ± 1.5 Hz; p < .001). Compared with Bi, uni-res had a significantly greater area under the receiver operator curve (0.80 vs. 0.77; p < .05), specificity (86% vs. 76%; p < .001), and positive predictive value (43% vs. 30%; p < .001) for detecting low-voltage during AF. Similar improvements in specificity and positive predictive value were evident for uni-res versus uni-orig., Conclusion: Far-field EGM can be reliably removed from uni-orig using our novel, least-squares algorithm. Compared with Bi and uni-orig, uni-res is more accurate in detecting low-voltage regions during AF. This approach may improve substrate mapping and ablation during AF, and merits further study., (© 2021 Wiley Periodicals LLC.)
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- 2021
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123. COVID-19 pandemic and lockdown: Changing trends in Ophthalmology for in-patient and emergency services.
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Rehman O, Ichhpujani P, Nayyar S, and Kumar S
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- Comorbidity, Emergencies, Female, Humans, India epidemiology, Male, Pandemics, Retrospective Studies, COVID-19 epidemiology, Communicable Disease Control organization & administration, Emergency Medical Services organization & administration, Eye Diseases epidemiology, Ophthalmology trends, Quarantine, SARS-CoV-2
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Purpose: The aim of this study was to evaluate the changing trends in terms of patient load, presenting complaints, surgical procedures and resource utilization in a multispeciality tertiary care hospital after lockdown due to COVID-19., Methods: Retrospective., data were collected from Ophthalmology in-patient and emergency services of a government medical college and multispecialty tertiary care hospital in North India. Data pertaining to patient census, presenting complaints, surgical procedures and resource consumption were compared in the 6-month period (March 25 to September 30, 2020) following national lockdown and subsequent gradual unlock to data of same time period last year., Results: A total of 1152 new patients visited Ophthalmology emergency service, whereas 324 sought tele-ophthalmology consultation., Majority were males (61.8%, n = 712), whereas average age of presentation was 34 ± 7.2 years. The number., of patients seeking emergency ophthalmic care reduced by 23.9% in the current year, in-patient record reduced by 96.53% and number of surgeries reduced by 98.13%. Tele-ophthalmology services comprised 21.95% of the total patient load. Use of triple layered surgical masks increased by 85.7%, use of disposable gloves increased by 89.5% but interestingly the availability of chlorhexidine hand rub fell by 15.9%, in the current year compared to last year., Conclusion: COVID-19 pandemic and lockdown have reduced the number of patients visiting tertiary health care facility for ophthalmic care. As manpower and resource consumption has increased, smart management is needed to tackle the current scenario efficiently. Tele-ophthalmology must be promoted and we must understand the changing trends to plan for the future accordingly., Competing Interests: None
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- 2021
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124. Focal and pseudo/rotational activations in human atrial fibrillation defined with automated periodicity mapping.
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Nayyar S, Ha ACT, Timmerman N, Suszko A, Ragot D, and Chauhan VS
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- Aged, Electrophysiologic Techniques, Cardiac, Heart Atria surgery, Humans, Middle Aged, Atrial Fibrillation diagnosis, Atrial Fibrillation surgery, Catheter Ablation, Pulmonary Veins diagnostic imaging, Pulmonary Veins surgery
- Abstract
Introduction: Defining atrial fibrillation (AF) wave propagation is challenging unless local signal features are discrete or periodic. Periodic focal or rotational activity may identify AF drivers. Our objective was to characterize AF propagation at sites with periodic activation to evaluate the prevalence and relationship between focal and rotational activation., Methods: We included 80 patients (61 ± 10 years, persistent AF 49%) from the FaST randomized trial that compared the efficacy of adjunctive focal site ablation versus pulmonary vein isolation. Patients underwent left atrial (LA) activation mapping with a 20-pole circular catheter during spontaneous or induced AF. Five-second bipolar and unipolar electrograms in AF were analyzed. Periodic sites were identified by spectral analysis of the bipolar electrogram. Activation maps of periodic sites were constructed using an automated, validated tracking algorithm, and classified into three patterns: focal sites (FS), rotation (RO), or pseudo-rotation (pRO)., Results: The most common propagation pattern at periodic sites was FS for 5-s in all patients (4.9 ± 1.9 per patient). RO and pRO were observed in two and seven patients, respectively, but were all transient (3-5 cycles). Activation from a FS evolved into transient RO/pRO in five patients. No patient had autonomous RO/pRO activations. Patients with RO/pRO had greater LA surface area with periodicity (78 ± 7 vs. 63 ± 16%, p = .0002) and shorter LA periodicity CL (166 ± 10 vs. 190±28 ms, p = .0001) than the rest., Conclusion: Using automated, regional AF periodicity mapping, FS is more prevalent and temporally stable than RO/pRO. Most RO/pRO evolve from neighboring FS. These findings and their implications for AF maintenance require verification with global, panoramic mapping., (© 2020 Wiley Periodicals LLC.)
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- 2021
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125. The results of sequential swallowing assessments after total laryngectomy for laryngeal and hypopharyngeal malignancies.
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Balaji A, Thiagarajan S, Dhar H, Malik A, Bhattacharjee A, Chakraborthy A, Shah S, Nayyar S, and Chaukar D
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- Deglutition, Humans, Laryngectomy, Treatment Outcome, Deglutition Disorders diagnosis, Deglutition Disorders etiology, Hypopharyngeal Neoplasms surgery, Laryngeal Neoplasms surgery, Larynx
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Background: Swallowing after total laryngectomy (TL) is altered and the swallowing related issues are largely underreported. It is important to identify factors that may negatively influence swallowing after TL in order to rehabilitate these patients appropriately., Methods: The study included patients who underwent TL from June 2015 to November 2017 for laryngeal and hypopharyngeal malignancy. Sequential swallowing assessment was done in these patients over time. The assessments were done using the FOIS scale and the PSS-HN normalcy of diet scores and analysed to assess the presence of swallowing related issues, factors influencing swallowing and its recovery over time., Results: Sixty-seven who underwent total laryngectomy (TL) were included in the study. Swallowing assessments were done once in 3 months. Overall there was an improvement in swallowing over time. Both the FOIS (Median score of 3.82 in first to 5.77 in the fifth visit) and the PSS-HN scores (median score of 33.63 at first visit to 63.66 at fifth visit) improved over time. Patients undergoing TL after treatment failure with chemoradiotherapy (p value < 0.001) and those with advanced stage disease (p-value < 0.001) did poorly in terms of swallowing. At the last follow up only 8 patients were dependent on feeding tube; the rest of the patients were able to take food orally., Conclusion: Following total laryngectomy swallowing gradually improves in the first 18 months after surgery. It is essential to identify factors influencing swallowing negatively so that these patients can get appropriate attention to improve swallowing.
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- 2020
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126. A compound problem of sensing and pacing alternans.
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Nayyar S
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- 2020
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127. Signature signal strategy: Electrogram-based ventricular tachycardia mapping.
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Nayyar S, Downar E, Bhaskaran AP, Massé S, and Nanthakumar K
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- Humans, Body Surface Potential Mapping methods, Heart Conduction System physiopathology, Heart Rate physiology, Heart Ventricles physiopathology, Tachycardia, Ventricular physiopathology
- Abstract
Multiple decades of work have recognized complexities of substrates responsible for ventricular tachycardia (VT). There is sufficient evidence that 3 critical components of a re-entrant VT circuit, namely, region of slow conduction, zone of unidirectional block, and exit site, are located in spatial vicinity to each other in the ventricular scar. Each of these components expresses characteristic electrograms in sinus rhythm, at initiation of VT, and during VT, respectively. Despite this, abnormal electrograms are widely targeted without appreciation of these signature electrograms during contemporary VT ablation. Our aim is to stimulate physiology-based VT mapping and a targeted ablation of VT. In this article, we focus on these 3 underappreciated aspects of the physiology of ischemic scar-related VT circuits that have practical applications during a VT ablation procedure. We explore the anatomic and functional elements underlying these distinctive bipolar electrograms, specifically the contribution of tissue branching, conduction restitution, and wave curvature to the substrate, as they pertain to initiation and maintenance of VT. We propose a VT ablation approach based on these 3 electrogram features that can be a potential practical means to recognize critical elements of a VT circuit and target ablation., (Copyright © 2020 Heart Rhythm Society. All rights reserved.)
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- 2020
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128. High-resolution, live, directional mapping.
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Deno DC, Bhaskaran A, Morgan DJ, Goksu F, Batman K, Olson GK, Magtibay K, Nayyar S, Porta-Sánchez A, Laflamme MA, Massé S, Aukhojee P, Nair K, and Nanthakumar K
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- Animals, Arrhythmias, Cardiac diagnosis, Disease Models, Animal, Humans, Reproducibility of Results, Swine, Arrhythmias, Cardiac physiopathology, Body Surface Potential Mapping methods, Heart Ventricles physiopathology
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- 2020
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129. Microvolt QRS Alternans Without Microvolt T-Wave Alternans in Human Cardiomyopathy: A Novel Risk Marker of Late Ventricular Arrhythmias.
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Suszko A, Nayyar S, Labos C, Nanthakumar K, Pinter A, Crystal E, and Chauhan VS
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- Aged, Algorithms, Arrhythmias, Cardiac etiology, Arrhythmias, Cardiac prevention & control, Canada epidemiology, Cardiomyopathies complications, Cardiomyopathies therapy, Case-Control Studies, Defibrillators, Implantable adverse effects, Female, Heart Ventricles pathology, Humans, Male, Middle Aged, Noise adverse effects, Prospective Studies, Risk Factors, Tachycardia, Ventricular etiology, Tachycardia, Ventricular prevention & control, Arrhythmias, Cardiac physiopathology, Cardiomyopathies physiopathology, Electrocardiography methods, Heart Ventricles physiopathology, Tachycardia, Ventricular physiopathology
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Background Action potential alternans can induce ventricular tachyarrhythmias and manifest on the surface ECG as T-wave alternans (TWA) and QRS alternans (QRSA). We sought to evaluate microvolt QRSA in cardiomyopathy patients in relation to TWA and ventricular tachyarrhythmia outcomes. Methods and Results Prospectively enrolled cardiomyopathy patients (n=100) with prophylactic defibrillators had 12-lead ECGs recorded during ventricular pacing from 100 to 120 beats/min. QRSA and TWA were quantified in moving 128-beat segments using the spectral method. Segments were categorized as QRSA positive (QRSA+) and/or TWA positive (TWA+) based on ≥2 precordial leads having alternans magnitude >0 and signal:noise >3. Patients were similarly categorized based on having ≥3 consecutive segments with alternans. TWA+ and QRSA+ occurred together in 31% of patients and alone in 18% and 14% of patients, respectively. Although TWA magnitude (1.4±0.4 versus 4.7±1.0 µV, P <0.01) and proportion of TWA+ studies (16% versus 46%, P <0.01) increased with rate, QRSA did not change. QRS duration was longer in QRSA+ than QRSA-negative patients (138±23 versus 113±26 ms, P <0.01). At 3.5 years follow-up, appropriate defibrillator therapy or sustained ventricular tachyarrhythmia was greater in QRSA+ than QRSA-negative patients (30% versus 8%, P =0.02) but similar in TWA+ and TWA-negative patients. Among QRSA+ patients, the event rate was greater in those without TWA (62% versus 21%, P =0.02). Multivariable Cox analysis revealed QRSA+ (hazard ratio [HR], 4.6; 95% CI, 1.5-14; P =0.009) and QRS duration >120 ms (HR, 4.1; 95% CI, 1.3-12; P =0.014) to predict events. Conclusions Microvolt QRSA is novel phenomenon in cardiomyopathy patients that can exist without TWA and is associated with QRS prolongation. QRSA increases the risk of ventricular tachyarrhythmia 4-fold, which merits further study as a risk stratifier.
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- 2020
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130. Lateral tunnel Fontan atrial tachycardia ablation trans-baffle access is not mandatory as the initial strategy.
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Bhaskaran A, Nayyar S, Charla P, Saeed Y, Haldar S, Porta-Sánchez A, Kugamoorthy P, Hans A, Jons C, Oechslin E, Hickey E, Harris L, Silversides C, Roche SL, Downar E, Nanthakumar K, and Nair K
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- Heart Atria surgery, Humans, Retrospective Studies, Tachycardia surgery, Treatment Outcome, Catheter Ablation, Tachycardia, Supraventricular diagnostic imaging, Tachycardia, Supraventricular surgery
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Background: Mapping and ablation of atrial tachycardia (AT) is commonly performed in lateral tunnel Fontan (LTF) patients, yet there is little information on the need of baffle puncture to access the pulmonary venous atrium (PVA). This study aimed to evaluate the most common chamber location of critical sites for majority of AT in LTF patients., Methods: Consecutive LTF patients underwent catheter-based high-density mapping and ablation of AT from Nov. 2015 to Mar. 2019. Critical sites were identified by a combination of activation and entrainment mapping. Acute procedural success was defined as AT termination with ablation and non-inducibility of any AT. Predictors for ablation failure were evaluated in retrospect., Results: Fifteen catheter ablation procedures were performed in 9 patients. A total of 15 clinical ATs (mean TCL 369 ± 91 ms) were mapped. The mechanism was macro re-entry in 11 (73%) and micro re-entry in 2. In 11 ATs (73%), 94 ± 5% of tachycardia cycle length (TCL) were mapped inside the tunnel. The commonest site of successful ablation in the tunnel was on the lateral wall (60%). Trans-baffle access was obtained during 5 of 15 procedures (33%). Overall, procedural success was achieved in 9 of 15 procedures (60%). There were no complications. Recurrence of AT was 42% over a follow-up period of 4.3 ± 3.2 years. Faster TCL of 200-300 ms showed a trend towards ablation failure, (OR 17, 95% CI 0.7 to 423, p = 0.08)., Conclusions: Catheter ablation can be performed effectively for ATs in LTF patients usually from inside the tunnel. ATs with critical sites in the PVA are uncommon. This information will help plan ablation in LTF patients without resorting to initial trans-baffle access.
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- 2020
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131. To the Editor- Determinants of bipolar amplitude.
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Nayyar S, Massé S, and Nanthakumar K
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- 2020
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132. Focal source and trigger mapping in atrial fibrillation: Randomized controlled trial evaluating a novel adjunctive ablation strategy.
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Chauhan VS, Verma A, Nayyar S, Timmerman N, Tomlinson G, Porta-Sanchez A, Gizurarson S, Haldar S, Suszko A, Ragot D, and Ha ACT
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- Aged, Female, Humans, Male, Middle Aged, Recurrence, Treatment Outcome, Atrial Fibrillation diagnosis, Atrial Fibrillation surgery, Catheter Ablation adverse effects, Catheter Ablation methods, Pulmonary Veins surgery
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Background: Intraoperative mapping has demonstrated focal activations during human atrial fibrillation (AF). These putative AF sources can manifest sustained periodic bipolar and unipolar QS electrograms (EGMs). We have automated the detection of these EGM features using our validated Focal Source and Trigger (FaST) computational algorithm., Objective: The purpose of this study was to conduct a randomized controlled pilot evaluating the feasibility and efficacy of FaST mapping/ablation as an adjunct to pulmonary vein isolation (PVI) in reducing AF recurrence., Methods: We randomized 80 patients with high-burden paroxysmal or persistent AF (age 61 ± 10 years; 75% male) to PVI alone (n = 41) or PVI+FaST mapping/ablation (n = 39). The primary endpoint was time to AF recurrence >30 seconds between 3 and 12 months after 1 procedure., Results: FaST sites were identified in all but 1 patient and were localized to pulmonary vein (PV) (2.1 ± 1.1 per patient) and extra-PV regions (2.8 ± 1.4 per patient). FaST mapping and ablation times were 27 ± 9 minutes and 8.5 ± 5 minutes, respectively. Patients with AF termination during ablation had greater AF cycle length prolongation with PVI+FaST than PVI (Δ20 ± 14 ms vs Δ5 ± 17 ms; P = .046). Freedom from AF recurrence at 12 months was higher in PVI+FaST vs PVI for patients off antiarrhythmic drugs (74% vs 51%; hazard ratio 0.48; 95% confidence interval 0.21-1.08; P = .064) but did not quite reach statistical significance. Major adverse events were similar between the 2 groups., Conclusion: In this randomized controlled pilot, real-time FaST mapping provided an intuitive, automated approach for localizing focal AF sources. FaST ablation as an adjunct to PVI may reduce AF recurrence, which requires verification with a larger multicenter trial., (Copyright © 2019 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)
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- 2020
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133. Direct and indirect mapping of intramural space in ventricular tachycardia.
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Bhaskaran A, Nayyar S, Porta-Sánchez A, Jons C, Massé S, Magtibay K, Aukhojee P, Ha A, Bokhari M, Tung R, Downar E, and Nanthakumar K
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- Cardiac Surgical Procedures, Female, Humans, Male, Tachycardia, Ventricular diagnosis, Tachycardia, Ventricular surgery, Epicardial Mapping methods, Heart Ventricles physiopathology, Monitoring, Intraoperative methods, Tachycardia, Ventricular physiopathology
- Abstract
Background: The ventricular tachycardia (VT) circuit is often assumed to be located in the endocardium or epicardium. The plateauing success rate of VT ablation warrants reevaluation of this mapping paradigm., Objective: The purpose of this study was to resolve the intramural components of VT circuits by mapping in human hearts., Methods: Panoramic simultaneous endocardial-epicardial mapping (SEEM) during intraoperative mapping (IOM) was performed in human subjects. In explanted hearts (EH), SEEM and intramural multielectrode plunge needle mapping (NM) of the left ventricle were performed. Overall, 37 VTs (26 ischemic cardiomyopathy [ICM], 11 nonischemic cardiomyopathy [NICM]) were studied in 32 patients. Intraoperative SEEM was performed in 16 patients (16 ICM). Additionally, 16 explanted myopathic human hearts (9 NICM, 7 ICM) were studied in a Langendorff setup. Predominant intramural location of the VT was imputed by the absence of significant endocardial-epicardial activation during IOM (using SEEM and no NM) or by the presence of intramural activation spanning the entire cycle length (including mid-diastole) in EH (SEEM and NM)., Results: By IOM (SEEM), predominant endocardial activation (entire tachycardia cycle length including mid-diastolic activation) was present in 10 of 18 VTs (55%). In 8 of 18 VTs (44%), the VT circuit was presumed to be intramural due to incomplete diastolic activation in endocardium and epicardium. In EH (SEEM and NM), VT location was predominantly intramural, endocardial, and epicardial in 8 of 19 (42%), 5 of 19 (26%), and 1 of 19 VTs (5%), respectively., Conclusion: In a significant proportion of both ischemic and nonischemic ventricular tachycardias, the predominant activation was located in the intramural space., (Copyright © 2019 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)
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- 2020
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134. Foot rot tolerant transgenic rough lemon rootstock developed through expression of β-1,3-glucanase from Trichoderma spp.
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Sandhu JS, Nayyar S, Kaur A, Kaur R, Kalia A, Arora A, Kaur Y, Thind SK, and Chhabra G
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- Agrobacterium, Citrus genetics, Disease Resistance, Plant Diseases microbiology, Plants, Genetically Modified, Trichoderma genetics, Citrus microbiology, Glucan 1,3-beta-Glucosidase genetics, Phytophthora pathogenicity, Plant Diseases genetics, Trichoderma enzymology
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- 2019
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135. Assessment of Quality of Life of the Elderly Living in Rural and Urban Areas of Ambala District: A Comparative Study.
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Mittal A, Aggarwal A, Nayyar S, Thakral A, Natt HK, and Singh A
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Context: Aging is a natural process which universally affects all the human beings in the society. As the geriatric population is quiet vulnerable, They might suffer from mental and physical disabilities which consequently threatens their independence. Quality of life among the geriatric population is a global concern as it reflects the status of health and of well being among the set population., Aims: To assess the quality of life of elderly living in rural and urban areas and compare the role of socio-demographic factors influencing the quality of life of elderly., Settings and Design: It is a Community based Cross sectional study conducted in urban and rural field practice areas of MMIMSR, Mullana., Methods and Material: Convenience sampling was used. A total of 200 elderly were included in the study. A pretested semi structured questionnaire was used., Statistical Analysis: Data was analysed using SPSS 20.0., Results: According to the sex of the participants, male participants had a higher mean score for QOL as compared to the female participants. Higher mean score was found in each domain for the participants living with their spouses., Conclusions: The quality of life is better among the individuals who do not suffer from any chronic illness'. The health care services should be strengthened to provide for better healthcare to the elderlies for their morbid conditions., Competing Interests: There are no conflicts of interest., (Copyright: © 2019 Journal of Mid-life Health.)
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- 2019
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136. Letter by Nayyar and Fairley Regarding Article, "Intracardiac Delineation of Septal Conduction in Left Bundle Branch Block Patterns: Mechanistic Evidence of Left Intrahisian Block Circumvented by His Bundle Pacing".
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Nayyar S and Fairley L
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- Arrhythmias, Cardiac, Heart Conduction System, Heart Rate, Humans, Bundle of His, Bundle-Branch Block
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- 2019
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137. Quantification of abnormal QRS peaks predicts response to cardiac resynchronization therapy and tracks structural remodeling.
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Suszko AM, Nayyar S, Porta-Sanchez A, Das M, Pinter A, Crystal E, Tomlinson G, Dalvi R, and Chauhan VS
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- Female, Follow-Up Studies, Humans, Logistic Models, Male, Middle Aged, ROC Curve, Cardiac Resynchronization Therapy, Electrocardiography
- Abstract
Background: Although QRS duration (QRSd) is an important determinant of cardiac resynchronization therapy (CRT) response, non-responder rates remain high. QRS fragmentation can also reflect electrical dyssynchrony. We hypothesized that quantification of abnormal QRS peaks (QRSp) would predict CRT response., Methods: Forty-seven CRT patients (left ventricular ejection fraction = 23±7%) were prospectively studied. Digital 12-lead ECGs were recorded during native rhythm at baseline and 6 months post-CRT. For each precordial lead, QRSp was defined as the total number of peaks detected on the unfiltered QRS minus those detected on a smoothed moving average template QRS. CRT response was defined as >5% increase in left ventricular ejection fraction post-CRT., Results: Sixty-percent of patients responded to CRT. Baseline QRSd was similar in CRT responders and non-responders, and did not change post-CRT regardless of response. Baseline QRSp was greater in responders than non-responders (9.1±3.5 vs. 5.9±2.2, p = 0.001) and decreased in responders (9.2±3.6 vs. 7.9±2.8, p = 0.03) but increased in non-responders (5.5±2.3 vs. 7.5±2.8, p = 0.049) post-CRT. In multivariable analysis, QRSp was the only independent predictor of CRT response (Odds Ratio [95% Confidence Interval]: 1.5 [1.1-2.1], p = 0.01). ROC analysis revealed QRSp (area under curve = 0.80) to better discriminate response than QRSd (area under curve = 0.67). Compared to QRSd ≥150ms, QRSp ≥7 identified response with similar sensitivity but greater specificity (74 vs. 32%, p<0.05). Amongst patients with QRSd <150ms, more patients with QRSp ≥7 responded than those with QRSp <7 (75 vs. 0%, p<0.05)., Conclusions: Our novel automated QRSp metric independently predicts CRT response and decreases in responders. Electrical dyssynchrony assessed by QRSp may improve CRT selection and track structural remodeling, especially in those with QRSd <150ms., Competing Interests: The authors have declared that no competing interests exist.
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- 2019
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138. Omnipolarity applied to equi-spaced electrode array for ventricular tachycardia substrate mapping.
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Porta-Sánchez A, Magtibay K, Nayyar S, Bhaskaran A, Lai PFH, Massé S, Labos C, Qiang B, Romagnuolo R, Masoudpour H, Biswas L, Ghugre N, Laflamme M, Deno DC, and Nanthakumar K
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- Animals, Electrocardiography methods, Prognosis, Swine, Cicatrix complications, Cicatrix pathology, Cicatrix physiopathology, Electrophysiologic Techniques, Cardiac instrumentation, Electrophysiologic Techniques, Cardiac methods, Heart physiopathology, Myocardial Infarction pathology, Myocardial Infarction physiopathology, Myocardium pathology, Tachycardia, Ventricular diagnosis, Tachycardia, Ventricular etiology, Tachycardia, Ventricular physiopathology
- Abstract
Aims: Bipolar electrogram (BiEGM)-based substrate maps are heavily influenced by direction of a wavefront to the mapping bipole. In this study, we evaluate high-resolution, orientation-independent peak-to-peak voltage (Vpp) maps obtained with an equi-spaced electrode array and omnipolar EGMs (OTEGMs), measure its beat-to-beat consistency, and assess its ability to delineate diseased areas within the myocardium compared against traditional BiEGMs on two orientations: along (AL) and across (AC) array splines., Methods and Results: The endocardium of the left ventricle of 10 pigs (three healthy and seven infarcted) were each mapped using an Advisor™ HD grid with a research EnSite Precision™ system. Cardiac magnetic resonance images with late gadolinium enhancement were registered with electroanatomical maps and were used for gross scar delineation. Over healthy areas, OTEGM Vpp values are larger than AL bipoles by 27% and AC bipoles by 26%, and over infarcted areas OTEGM Vpp values are 23% larger than AL bipoles and 27% larger than AC bipoles (P < 0.05). Omnipolar EGM voltage maps were 37% denser than BiEGM maps. In addition, OTEGM Vpp values are more consistent than bipolar Vpps showing less beat-by-beat variation than BiEGM by 39% and 47% over both infarcted and healthy areas, respectively (P < 0.01). Omnipolar EGM better delineate infarcted areas than traditional BiEGMs from both orientations., Conclusion: An equi-spaced electrode grid when combined with omnipolar methodology yielded the largest detectable bipolar-like voltage and is void of directional influences, providing reliable voltage assessment within infarcted and non-infarcted regions of the heart., (© The Author(s) 2019. Published by Oxford University Press on behalf of the European Society of Cardiology.)
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- 2019
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139. Exit sites on the epicardium rarely subtend critical diastolic path of ischemic VT on the endocardium: Implications for noninvasive ablation.
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Bhaskaran A, Nayyar S, Porta-Sánchez A, Haldar S, Bokhari M, Massé S, Liang T, Zehra N, Farid T, Downar E, and Nanthakumar K
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- Action Potentials, Adult, Electrocardiography, Epicardial Mapping, Female, Humans, Male, Middle Aged, Myocardial Ischemia diagnosis, Myocardial Ischemia physiopathology, Predictive Value of Tests, Retrospective Studies, Tachycardia, Ventricular diagnosis, Tachycardia, Ventricular etiology, Tachycardia, Ventricular physiopathology, Time Factors, Treatment Outcome, Catheter Ablation adverse effects, Endocardium physiopathology, Heart Rate, Myocardial Ischemia complications, Pericardium physiopathology, Tachycardia, Ventricular surgery
- Abstract
Background: Noninvasive electrocardiographic mapping of ventricular tachycardia (VT) and ablation using stereotactic radiotherapy was recently reported. This strategy does not directly evaluate the critical diastolic components and assumes that the epicardial exit site of VT subtends closely over the endocardial mid-diastolic isthmus., Objective: To determine if the epicardial exit site of VT spatially corresponds to the critical diastolic components of ischemic scar-related VT., Materials and Methods: Intraoperative simultaneous endocardial and epicardial mapping were performed during VT using a 112-bipole endocardial balloon and 112-bipole epicardial sock array. In eight patients, nine VTs having entire diastolic circuit mapped were included in the study. The diastolic path and VT-exit sites (epicardial and endocardial) were determined., Results: The diastolic path was mapped in the endocardium for all nine VTs (median length, 50; interquartile range [IQR], 28 mm). The tachycardia cycle length ranged from 210-500 ms. The VT-exit site was early in the endocardium for six VTs and on the epicardium for three VTs. The mid-diastolic isthmus and endocardial exit site of the six endocardial VTs were spatially distant from their epicardial exit site by a median distance of 32 and 27 mm, respectively. For the three VTs with an early epicardial exit, the isthmus and endocardial exit sites were distant from the epicardial exit site by a median distance of 34 and 38 mm, respectively., Conclusion: The epicardial exit site and the mid-diastolic isthmus sites were spatially distant and discrepant. Surface electrocardiography (ECG)-derived strategy in identifying epicardial exit site to select noninvasive ablation targets is prone to identify epicardial exit sites and may not identify critical targets in ischemic scar VT., (© 2019 Wiley Periodicals, Inc.)
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- 2019
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140. Differential pacing from two sites to diagnose risk of ventricular arrhythmia and death.
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Nayyar S, Kuklik P, Tomlinson G, Suszko A, and Chauhan VS
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- Aged, Arrhythmias, Cardiac etiology, Arrhythmias, Cardiac physiopathology, Cardiomyopathies complications, Cardiomyopathies physiopathology, Electrophysiologic Techniques, Cardiac, Female, Humans, Male, Middle Aged, Prospective Studies, Risk Assessment, Arrhythmias, Cardiac diagnosis, Arrhythmias, Cardiac mortality, Electrocardiography methods
- Abstract
Background: QRS abnormalities may not be apparent in sinus rhythm in electrically stable cardiomyopathy patients who can have quiescent but highly arrhythmogenic substrate. Here, we test the hypothesis that differential changes in QRS construction during right-ventricular apex pacing (RVP) as opposed to atrial pacing (AP) will identify latent substrate for ventricular arrhythmias (VA) and death., Methods: Forty patients with cardiomyopathy free of VA underwent baseline 114-electrode body-surface electrocardiogram during AP (100 beats per minute [bpm]) and RVP (100 and 120 bpm). The filtered-averaged QRS at each electrode was deconstructed into individual intra-QRS and post-QRS ventricular myopotentials (V
MP ). The primary outcome was VA or death. Prognostic accuracy of VMP was validated using V1 to V6 leads in another prospective cohort of 44-cardiomyopathy patients., Results: Twenty-six patients were eligible for initial analysis. After 5 ± 2 years of follow-up, eight (31%) patients had VA (VAPos ) while rest were uneventful (VANeg ). During AP100 , VAPos patients expressed more VMP than VANeg patients (16 ± 1 vs 12 ± 1, P = 0.02). RVP100 and RVP120 in VAPos patients introduced an additional 5.5 ± 0.5 and 6.0 ± 0.5 VMP (P < 0.0001 vs AP100 ). The relative change with RVP120 versus AP100 in VANeg patients exceeded VAPos patients by 1.2 ± 0.5 VMP (P = 0.03). Increment in VMP count of <8 in lead-V5 with RVP120 compared to AP100 best predicted VA (area under curve 0.81, P = 0.01). In the validation cohort, primary outcome occurred in 13 (33%) patients. Native QRS features and AP100 alone failed to predict primary outcome. Patients with increment in VMP count of <8 in lead-V5 with RVP120 versus AP100 had 7.9-fold increased risk of primary outcome (95% confidence interval 1.01, 61.61; P = 0.049)., Conclusion: Cardiomyopathy patients at risk of VA or death perturb the QRS less than low-risk patients with differential pacing. This functional response may be useful to identify arrhythmogenic substrate., (© 2018 Wiley Periodicals, Inc.)- Published
- 2019
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141. Information theory to tachycardia therapy: electrogram entropy predicts diastolic microstructure of reentrant ventricular tachycardia.
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Nayyar S, Downar E, Beheshti M, Liang T, Massé S, Magtibay K, Bhaskaran A, Saeed Y, Vigmond E, and Nanthakumar K
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- Electrophysiologic Techniques, Cardiac, Entropy, Humans, Tachycardia, Ventricular therapy, Heart Rate, Information Theory, Models, Cardiovascular, Myocardial Contraction, Tachycardia, Ventricular physiopathology
- Abstract
There is no known strategy to differentiate which multicomponent electrograms in sinus rhythm maintain reentrant ventricular tachycardia (VT). Low entropy in the voltage breakdown of a multicomponent electrogram can localize conditions suitable for reentry but has not been validated against the classic VT activation mapping. We examined whether low entropy in a late and diversely activated ventricular scar region characterizes and differentiates the diastolic path of VT and represents protected tissue channels devoid of side branches. Intraoperative bipolar electrogram (Bi
EGM ) activation and entropy maps were obtained during sinus rhythm in 17 patients with ischemic cardiomyopathy and compared with diastolic activation paths of VT (total of 39 VTs). Mathematical modeling of a zigzag main channel with side branches was also used to further validate structural representation of low entropy in the ventricular scar. A median of one region per patient (range: 1-2 regions) was identified in sinus rhythm, in which BiEGM with the latest mean activation time and adjacent minimum entropy were assembled together in a high-activation dispersion region. These regions accurately recognized diastolic paths of 34 VTs, often to multiple inducible VTs within a single individual arrhythmogenic region. In mathematical modeling, side branching from the main channel had a strong influence on the BiEGM composition along the main channel. The BiEGM obtained from a long unbranched channel had the lowest entropy compared with those with multiple side branches. In conclusion, among a population of multicomponent sinus electrograms, those that demonstrate low entropy and are delayed colocalize to critical long-protected channels of VT. This information is pertinent for planning VT ablation in sinus rhythm. NEW & NOTEWORTHY Entropy is a measure to quantify breakdown in information. Electrograms from a protected tissue channel can only possess a few states in their voltage and thus less information. In contrast, current-load interactions from side branches in unprotected channels introduce a number of dissimilar voltage deflections and thus high information. We compare here a mapping approach based on entropy against a rigorous reference standard of activation mapping during VT and entropy was assessed in sinus rhythm.- Published
- 2019
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142. Determinants of atrial bipolar voltage: Inter electrode distance and wavefront angle.
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Beheshti M, Magtibay K, Massé S, Porta-Sanchez A, Haldar S, Bhaskaran A, Nayyar S, Glover B, Deno DC, Vigmond EJ, and Nanthakumar K
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- Action Potentials, Algorithms, Animals, Computer Simulation, Electrocardiography, Heart Ventricles diagnostic imaging, Humans, Models, Cardiovascular, Software, Swine, Arrhythmias, Cardiac diagnostic imaging, Electrodes, Electrophysiologic Techniques, Cardiac, Heart Atria diagnostic imaging
- Abstract
Background: Local bipolar electrogram (EGM) peak-to-peak voltage (Vpp) is currently used to characterise mapped myocardial substrate. However, how interelectrode distance and angle of wavefront incidence affect bipolar, Vpp values, in the current era of multi-electrode mapping is unknown., Objectives: To elucidate the effects of tissue and electrode geometry on bipolar Vpp measurements, when mapping healthy versus diseased atrial regions., Methods: A bidomain model of human atrial tissue was used to quantify the influence on Vpp values of various electrode configurations in healthy tissue, and tissue containing an unexcitable region. The orientation angle and interelectrode spacing of a surface bipole, and thickness and depth of the unexcitable core were serially varied. Results were validated with data obtained from isolated porcine hearts., Results: In healthy tissue, bipolar Vpp values increased with increasing interelectrode spacing and plateaued beyond a spacing of approximately 4 mm. The bipolar Vpp values in healthy tissue were relatively less sensitive to wavefront orientation angle with large interelectrode spacing. In diseased tissue, on the contrary, with increasing interelectrode spacing, bipolar Vpp values increased linearly without a plateau and were more sensitive to orientation angle. The bipolar Vpp values decreased with increasing thickness of the scar, with larger relative decrease in small bipoles than larger ones. Bipolar Vpp values increased with a progressively intramural location of fixed-size scar and became less distinguishable from healthy tissue especially for smaller interelectrode spacings., Conclusions: The scalable relationship established for interelectrode distances favour an electric-field-based assessment as opposed to traditional Vpp values as a tool for physiologically relevant measurement for mapping catheters with interelectrode spacing up to 4 mm. This will allow for universal assessment of myocardial health across catheters with varied spacing., (Copyright © 2018 Elsevier Ltd. All rights reserved.)
- Published
- 2018
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143. Quantifying the determinants of decremental response in critical ventricular tachycardia substrate.
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Beheshti M, Nayyar S, Magtibay K, Massé S, Porta-Sanchez A, Haldar S, Bhaskaran A, Vigmond E, and Nanthakumar K
- Subjects
- Arrhythmias, Cardiac physiopathology, Catheter Ablation methods, Electrocardiography, Heart, Heart Ventricles physiopathology, Humans, Tachycardia, Ventricular diagnosis, Electrophysiologic Techniques, Cardiac methods, Heart Conduction System physiopathology, Tachycardia, Ventricular physiopathology
- Abstract
Background: Decremental response evoked with extrastimulation (DEEP) is a useful tool for determining diastolic return path of ventricular tachycardia (VT). Though a targeted VT ablation is feasible with this approach, determinants of DEEP response have not been studied OBJECTIVES: To elucidate the effects of clinically relevant factors, specifically, the proximity of the stimulation site to the arrhythmogenic scar, stimulation wave direction, number of channels open in the scar, size of the scar and number of extra stimuli on decrement and entropy of DEEP potentials., Methods: In a 3-dimensional bi-domain simulation of human ventricular tissue (TNNP cell model), an irregular subendocardial myopathic region was generated. An irregular channel of healthy tissue with five potential entry branches was shaped into the myopathic region. A bipolar electrogram was derived from two electrodes positioned in the centre of the myopathic region. Evoked delays between far-field and local Electrogram (EGM) following an extrastimulus (S1-S2, 500-350 ms) were measured as the stimulation site, channel branches, and inexcitable tissue size were altered., Results: Stimulation adjacent to the inexcitable tissue from the side opposite to the point-of-entry produces longest DEEP delay. The DEEP delay shortens when the stimulation point is farther away from the scar, and it decreases maximally when stimulation is done from a site beside a conduction barrier. Entropy increases with S2 when stimulation site is from farther away. An unprotected channel structure with multiple side-branch openings had shorter DEEP delay compared to a protected channel structure with a paucity of additional side-branch openings and a point-of-entry on the side opposite to the pacing source. Addition of a second shorter extrastimulus did not universally lead to higher DEEP delay CONCLUSIONS: Location and direction of the wavefront in relation to scar entry and size of scar determine the degree of evoked response while the number of extrastimuli has a small additional decremental effect., (Copyright © 2018 Elsevier Ltd. All rights reserved.)
- Published
- 2018
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144. Do Progestin-Only Contraceptives Contribute to the Risk of Developing Depression as Implied by Beta-Arrestin 1 Levels in Leukocytes? A Pilot Study.
- Author
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Smith K, Nayyar S, Rana T, Archibong AE, Looney KR, and Nayyar T
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- Adolescent, Adult, Female, Humans, Pilot Projects, Risk Factors, Tennessee, Young Adult, Biomarkers blood, Contraception adverse effects, Contraceptives, Oral adverse effects, Depressive Disorder etiology, Leukocytes, Mononuclear chemistry, Progestins adverse effects, beta-Arrestin 1 blood
- Abstract
We reported previously that reduction in beta-arrestin 1 (β-AR 1) protein levels in peripheral blood mononuclear leukocytes (PBMC) significantly correlated with the severity of depressive symptoms in reproductive women. In this pilot study, we used β-AR 1 protein levels in PBMC as a marker for developing depressive symptoms and the Hamilton Depression Rating Scale (HAM-D) scores to assess potential mood-related side effects of oral contraceptive use for routine birth control among women. We evaluated 29 women in this study. We enrolled the participants in three groups: Estrogen-progestin combination-oral contraceptives (COC, n = 10), progestin-only contraceptives (POC, n = 12), and non-hormonal or no contraceptives (NC, n = 7). We determined the β-AR 1 protein levels in PBMCs by enzyme-linked immunosorbent assay (ELISA). We found that women in the POC group had significantly higher HAM-D scores compared to those in the COC ( p < 0.0004) and NC ( p < 0.004). The levels of β-AR 1 protein were significantly attenuated in women in the POC group compared to women in the NC group ( p = 0.03). Our findings suggest that the use of POC is a potential risk factor for developing depressive symptoms.
- Published
- 2018
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145. Reduced T wave alternans in heart failure responders to cardiac resynchronization therapy: Evidence of electrical remodeling.
- Author
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Nayyar S, Suszko A, Porta-Sanchez A, Dalvi R, and Chauhan VS
- Subjects
- Aged, Cardiomyopathy, Dilated diagnosis, Female, Follow-Up Studies, Humans, Male, Middle Aged, Prospective Studies, Signal Processing, Computer-Assisted, Treatment Outcome, Cardiac Resynchronization Therapy, Cardiomyopathy, Dilated physiopathology, Cardiomyopathy, Dilated therapy, Electrocardiography
- Abstract
Background: T-wave alternans (TWA), a marker of electrical instability, can be modulated by cardiac resynchronization therapy (CRT). The relationship between TWA and heart failure response to CRT has not been clearly defined., Methods and Results: In 40-patients (age 65±11 years, left ventricular ejection-fraction [LVEF] 23±7%), TWA was evaluated prospectively at median of 2 months (baseline) and 8 months (follow-up) post-CRT implant. TWA-magnitude (Valt >0μV, k≥3), its duration (d), and burden (Valt ·d) were quantified in moving 128-beat segments during incremental atrial (AAI, native-TWA) and atrio-biventricular (DDD-CRT) pacing. The immediate and long-term effect of CRT on TWA was examined. Clinical response to CRT was defined as an increase in LVEF of ≥5%. Native-TWA was clinically significant (Valt ≥1.9μV, k≥3) in 68% of subjects at baseline. Compared to native-TWA at baseline, DDD-CRT pacing at baseline and follow-up reduced the number of positive TWA segments, peak-magnitude, longest-duration and peak-burden of TWA (44±5 to 33±5 to 28±4%, p = 0.02 and 0.002; 5.9±0.8 to 4.1±0.7 to 3.8±0.7μV, p = 0.01 and 0.01; 97±9 to 76±8 to 67±8sec, p = 0.004 and <0.001; and 334±65 to 178±58 to 146±54μV.sec, p = 0.01 and 0.004). In addition, the number of positive segments and longest-duration of native-TWA diminished during follow-up (44±5 to 35±6%, p = 0.044; and 97±9 to 81±9sec, p = 0.02). Clinical response to CRT was observed in 71% of patients; the reduction in DDD-CRT paced TWA both at baseline and follow-up was present only in responders (interaction p-values <0.1)., Conclusion: Long-term CRT reduces the prevalence and magnitude of TWA. This CRT induced beneficial electrical remodeling is a marker of clinical response after CRT., Competing Interests: The authors have declared that no competing interests exist.
- Published
- 2018
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146. Cemented Compared with Uncemented Femoral Fixation in the Arthroplasty Treatment of Displaced Femoral Neck Fractures: A Critical Analysis Review.
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Chen KK, Nayyar S, Davidovitch RI, Vigdorchik JM, Iorio R, and Macaulay W
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- Humans, Treatment Outcome, Arthroplasty methods, Bone Cements, Femoral Neck Fractures surgery, Fracture Fixation methods
- Published
- 2018
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147. Early aseptic loosening of the Tritanium primary acetabular component with screw fixation.
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Long WJ, Nayyar S, Chen KK, Novikov D, Davidovitch RI, and Vigdorchik JM
- Abstract
Ultraporous acetabular components were developed to improve osseointegration and fit for increased longevity and better outcomes after total hip arthroplasty. There is a paucity of literature detailing this acetabular component's clinical performance, with even less detailing those with screw fixation. We identify 5 patients at our institution who underwent revision total hip arthroplasty for early aseptic acetabular cup loosening of an ultraporous acetabular component known as the Tritanium primary cup with secondary screw fixation. They all presented with groin and hip pain after index surgery and underwent follow-up radiographic examination consistent with component loosening requiring revision surgery. This case series reports on the risk of early acetabular cup loosening and its associated clinical presentation, workup, and surgical management in patients with the Tritanium primary cup augmented with screws.
- Published
- 2018
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148. Electrophysiologic features of protected channels in late postinfarction patients with and without spontaneous ventricular tachycardia.
- Author
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Nayyar S, Wilson L, Ganesan A, Sullivan T, Kuklik P, Young G, Sanders P, and Roberts-Thomson KC
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- Cardiac Catheterization methods, Catheter Ablation mortality, Cicatrix etiology, Cicatrix physiopathology, Electrophysiologic Techniques, Cardiac, Female, Follow-Up Studies, Humans, Male, Myocardial Infarction diagnostic imaging, Myocardial Infarction physiopathology, Myocardial Ischemia diagnostic imaging, Reference Values, Risk Assessment, Severity of Illness Index, Survival Rate, Time Factors, Treatment Outcome, Body Surface Potential Mapping methods, Catheter Ablation methods, Cicatrix diagnostic imaging, Imaging, Three-Dimensional, Myocardial Infarction etiology, Myocardial Ischemia complications
- Abstract
Purpose: Protected channels of surviving myocytes in late postinfarction ventricular scar predispose to ventricular tachycardia (VT). However, only a few patients develop VT spontaneously. We studied differences in electric remodeling and protected channels in late postinfarction patients with and without spontaneous VT., Methods: Patients with ischemic cardiomyopathy (ICM) with recurrent sustained monomorphic VT (n = 22) were compared with stable ICM patients without spontaneous VT (control group; n = 5). Left ventricular mapping was performed with a 20-pole catheter. Detailed pace mapping was used to identify channels of protected conduction, and confirmed, when feasible, by entrainment. Anatomical and electrophysiological properties of VT channels and non-VT channels in VT patients and channels in controls were evaluated., Results: Seventy-three (median 3) VTs were inducible in VT patients compared to two (median 0) in controls. The VT channels in VT patients (n = 57, 3 ± 1 per patient) were lengthier (mean ± SEM 53 ± 5 vs. 33 ± 4 vs. 24 ± 8 mm), had longer S-QRS (73 ± 4 vs. 63 ± 3 vs. 44 ± 8 ms), longer conduction time (103 ± 13 vs. 33 ± 4 vs. 24 ± 8 ms), and slower conduction velocity (CV) (0.85 ± 0.21 vs. 1.39 ± 0.20 vs. 1.31 ± 0.41 m/s) than non-VT channels in VT patients (n = 183, 8 ± 6 per patient) (p ≤ 0.01) and channels in controls (n = 46, 9 ± 8 per patient) (p ≤ 0.01). Additionally, non-VT channels in VT patients had longer S-QRS (p = 0.02); however, they were similar in length, conduction time, and CV compared to channels in controls., Conclusions: Channels supporting VT are lengthier, with longer conduction times and slower CV compared to channels in patients without spontaneous VT. These observations may explain why some ICM patients have spontaneous VT and others do not.
- Published
- 2018
- Full Text
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149. Twisting and Turning to Find an Explanation for Torsades de Pointes.
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Nayyar S, Porta-Sánchez A, and Nanthakumar K
- Subjects
- Animals, Dogs, Electrocardiography, Atrioventricular Block, Long QT Syndrome, Torsades de Pointes
- Published
- 2017
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150. Visual outcome and its prognostic factors in patients presenting with ocular war injuries at an army hospital in Pakistan.
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Hassan Naqvi SA, Malik S, Syed ZUD, Anwar SB, and Nayyar S
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- Adult, Armed Conflicts, Humans, Male, Pakistan epidemiology, Prognosis, Treatment Outcome, Visual Acuity, Young Adult, Blast Injuries diagnosis, Blast Injuries epidemiology, Eye Injuries diagnosis, Eye Injuries epidemiology, Military Personnel statistics & numerical data, Wounds, Nonpenetrating diagnosis, Wounds, Nonpenetrating epidemiology
- Abstract
Objective: To determine the visual outcome and its prognostic factors in patients presenting with ocular war injuries., Methods: This descriptive, observational study was conducted at the Combined Military Hospital, Peshawar, Pakistan, from June 2012 to March 2016, and comprised soldiers with ocular war injuries. Informed consent was obtained from all participants. A predesigned proforma was used to record patient's demographic details along with the cause, side, type and severity of injury. Injuries were classified as open globe or closed globe injuries. Ocular trauma score grade was used to describe the severity of injury., Results: There were 210 participants with an overall mean age of 29.34±5.35 years (range: 20-43 years). All of them were male. Left side was more frequently involved, i.e. in 126(60%) cases. The most frequent underlying cause was improvised explosive device blast injury 114(54.3%), followed by blunt trauma 42(20%) and road traffic accidents 24(11.4%). Closed globe injuries were more frequent and were recorded in 120(57.1%) patients. The visual outcome was good in 62(29.5%) patients, followed by fair in 51(24.3%) patients while 51(24.3%) patients had worst visual outcome. When stratified, there was no significant difference of worst visual outcome with patient's age (p=0.279). However, improvised explosive device blast (p=0.002), open globe injury (p=0.000), ocular trauma score grade 1; open globe (p=0.049), closed globe (p=0.003) were associated with significantly higher frequency of worst visual outcome. Zone-III injury was also prognostic of worst visual outcome, but the difference was significant only in case of open globe injury (p=0.003)., Conclusions: Improvised explosive device blast, open globe injury and ocular trauma score grade 1 were poor prognostic features and resulted in significantly higher frequency of poor visual outcome.
- Published
- 2017
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