Search

Background: Patients who have recurrent atrial fibrillation (AF) following redo catheter ablation may eventually be managed with a pace-and-ablate approach, involving pacemaker implant followed by atrioventricular nodal ablation (AVNA). We sought to determine which factors would predict subsequent AVNA in patients undergoing redo AF ablation. Methods: We analyzed patients undergoing redo AF ablations between 2013 and 2019 at our institution. Follow-up was censored on December 31, 2021. Patients with no available follow- up data were excluded. Time-to-event analysis with Cox proportional hazard regression was used to compare those who underwent AVNA to those who did not. Results: A total of 467 patients were included, of whom 39 (8.4%) underwent AVNA. After multivariable adjustment, female sex (aHR 4.68 [95% CI 2.30-9.50]; p < 0.001), ischemic heart disease (aHR 2.99 [95% CI 1.25-7.16]; p = 0.014), presence of a preexisting pacemaker (aHR 3.25 [95% CI 1.10-9.60]; p = 0.033), and persistent AF (aHR 2.22 [95% CI 1.07-4.59]; p = 0.032) were associated with increased risk of subsequent AVNA requirement. Conclusion: Female sex, ischemic heart disease, and persistent AF may be useful clinical predictors of the requirement for subsequent AVNA and may be considered as part of shared clinical decision making. [ABSTRACT FROM AUTHOR]

Introduction: Pulmonary vein isolation (PVI) is often performed under general anaesthesia (GA) or deep sedation. Anaesthetic availability is limited in many centers, and deep sedation is prohibited in some countries without anaesthetic support. Very high‐power short duration (vHPSD—90W/4 s) PVI using the Q‐Dot catheter is generally well tolerated under mild conscious sedation (MCS) though an understanding of catheter stability and long‐term effectiveness is lacking. We analyzed lesion metrics and 12‐month freedom from atrial arrythmia with this approach. Methods: Our approach to radiofrequency (RF) PVI under MCS is standardized and includes a single catheter approach with a steerable sheath. We identified patients undergoing Q‐Dot RF PVI between March 2021 and December 2022 in our center, comparing those undergoing vHPSD ablation under MCS (90W/MCS) against those undergoing 50 W ablation under GA (50 W/GA) up to 12 months of follow‐up. Data were extracted from clinical records and the CARTO system. Results: Eighty‐three patients met our inclusion criteria (51 90W/MCS; 32 50 W/GA). Despite shorter ablation times (353 vs. 886 s; p <.001), the 90 W/MCS group received more lesions (median 87 vs. 58, p <.001), resulting in similar procedure times (149.3 vs. 149.1 min; p =.981). PVI was achieved in all cases, and first pass isolation rates were similar (left wide antral circumferential ablation [WACA] 82.4% vs. 87.5%, p =.758; right WACA 74.5% vs. 78.1%, p =.796; 90 W/MCS vs. 50 W/GA respectively). Analysis of 6647 ablation lesions found similar mean impedance drops (10.0 ± 1.9 Ω vs. 10.0 ± 2.2 Ω; p =.989) and mean contact force (14.6 ± 2.0 g vs. 15.1 ± 1.6 g; p =.248). Only median 2.5% of lesions in the 90 W/MCS cohort failed to achieve ≥ 5 Ω drop. In the 90 W/MCS group, there were no procedural related complications, and 12‐month freedom from atrial arrhythmia was observed in 78.4%. Conclusion: vHPSD PVI is feasible under MCS, with encouraging acute and long‐term procedural outcomes. This provides a compelling option for centers with limited anaesthetic support. [ABSTRACT FROM AUTHOR]

Background: Fontan surgery, a palliative procedure for single ventricle patients, often leads to the need for permanent pacing. Epicardial pacing has limitations, while transvenous pacing carries risks in the Fontan circulation. This case series introduces a novel approach of leadless pacemaker implantation in the extra‐cardiac Fontan (ECF) cohort to overcome these limitations. Methods: The study includes four cases of leadless pacemaker (Micra™) implantation in patients with ECF. Procedures were performed under general anesthesia with guidance from trans‐esophageal echocardiography. Various access routes were used, including trans‐carotid and trans‐fenestration approaches. Procedural details, parameters, and follow‐up data were collected. Results: All leadless pacemaker implantations were successful, with satisfactory electrical parameters and stable pacing postprocedural outcomes during short‐term follow‐up. One patient required closure of their fenestration for symptomatic desaturation post procedurally. Conclusions: Leadless pacemaker implantation via trans‐carotid and trans‐fenestration approaches appears to be a feasible back up option for pacing in Fontan patients where other options have been exhausted or there is a patient choice to avoid surgery. These techniques provide an option to avoid leaded systems or epicardial pacing, reducing the need for multiple thoracotomies and addressing challenges associated with surgical pacing leads. Further studies are needed to evaluate long‐term outcomes and assess the broader application of leadless pacemakers in the Fontan population. [ABSTRACT FROM AUTHOR]

Coarctation of the aorta (CoA) accounts for approximately 5–8% of all congenital heart defects. Depending on the severity of the CoA and the presence of associated cardiac lesions, the clinical presentation and age vary. Developments in diagnosis and management have improved outcomes in this patient population. Even after timely repair, it is important to regularly screen for hypertension. Patients with CoA require lifelong follow-up with a congenital heart disease specialist as these patients may develop recoarctation and complications at the repair site and remain at enhanced cardiovascular risk throughout their lifetime. [ABSTRACT FROM AUTHOR]

Background Ebstein's anomaly is a rare condition due to incomplete delamination of the tricuspid valve (TV) leaflets with downward displacement of the proximal leaflet attachments. It is associated with a smaller functional right ventricle (RV) and tricuspid regurgitation (TR) that is typically treated with TV replacement or repair. However, future re-intervention poses challenges. We describe a multidisciplinary team approach to re-intervention in a pacing-dependant Ebstein patient with severe bioprosthetic TV regurgitation. Case summary A 49-year-old female patient underwent bioprosthetic TV replacement for severe TR in Ebstein's. Post-operatively, she developed complete atrioventricular (AV) block necessitating the implantation of a permanent pacemaker which included a coronary sinus (CS) lead as the ventricular lead. Five years later, she presented with syncope due to a failing ventricular pacing lead, and a new RV lead was positioned across the TV bioprosthesis due to the lack of CS options. Two years later, she presented with breathlessness and lethargy with severe TR identified on transthoracic echocardiography. She successfully underwent a percutaneous leadless pacemaker implant, extraction of existing pacing system, and implantation of valve-in-valve TV. Discussion Patients with Ebstein's anomaly typically undergo TV repair or replacement. Following surgical intervention, owing to the anatomical location, patients can develop AV block requiring a pacemaker. Pacemaker implantation may involve a CS lead to avoid placing a lead across the new TV in efforts to avoid lead induced TR. Over time, these patients not uncommonly require re-intervention that can be challenging especially in pacing-dependant patients with leads across the TV. [ABSTRACT FROM AUTHOR]

Our aim was to investigate in a real-life setting the use of machine learning for modelling the postprandial glucose concentrations in morbidly obese patients undergoing Roux-en-Y gastric bypass (RYGB) or one-anastomosis gastric bypass (OAGB). As part of the prospective randomized open-label trial (RYSA), data from obese (BMI ≥35 kg/m2) non-diabetic adult participants were included. Glucose concentrations, measured with FreeStyle Libre, were recorded over 14 preoperative and 14 postoperative days. During these periods, 3-day food intake was self-reported. A machine learning model was applied to estimate glycaemic responses to the reported carbohydrate intakes before and after the bariatric surgeries. Altogether, 10 participants underwent RYGB and 7 participants OAGB surgeries. The glucose concentrations and carbohydrate intakes were reduced postoperatively in both groups. The relative time spent in hypoglycaemia increased regardless of the operation (RYGB, from 9.2 to 28.2%; OAGB, from 1.8 to 37.7%). Postoperatively, we observed an increase in the height of the fitted response curve and a reduction in its width, suggesting that the same amount of carbohydrates caused a larger increase in the postprandial glucose response and that the clearance of the meal-derived blood glucose was faster, with no clinically meaningful differences between the surgeries. A detailed analysis of the glycaemic responses using food diaries has previously been difficult because of the noisy meal data. The utilized machine learning model resolved this by modelling the uncertainty in meal times. Such an approach is likely also applicable in other applications involving dietary data. A marked reduction in overall glycaemia, increase in postprandial glucose response, and rapid glucose clearance from the circulation immediately after surgery are evident after both RYGB and OAGB. Whether nondiabetic individuals would benefit from monitoring the post-surgery hypoglycaemias and the potential to prevent them by dietary means should be investigated. The use of a novel machine learning model was applicable for combining patient-reported data and time-series data in this clinical study. Marked increase in postprandial glucose concentrations and rapid glucose clearance were observed after both Roux-en-Y gastric bypass and one-anastomosis gastric bypass surgeries. Whether nondiabetic individuals would benefit from monitoring the post-surgery hypoglycaemias and the potential to prevent them by dietary means should be investigated. [ABSTRACT FROM AUTHOR]

Estimating the impact of a treatment on a given response is needed in many biomedical applications. However, methodology is lacking for the case when the response is a continuous temporal curve, treatment covariates suffer extensively from measurement error, and even the exact timing of the treatments is unknown. We introduce a novel method for this challenging scenario. We model personalized treatment-response curves as a combination of parametric response functions, hierarchically sharing information across individuals, and a sparse Gaussian process for the baseline trend. Importantly, our model accounts for errors not only in treatment covariates, but also in treatment timings, a problem arising in practice for example when data on treatments are based on user self-reporting. We validate our model with simulated and real patient data, and show that in a challenging application of estimating the impact of diet on continuous blood glucose measurements, accounting for measurement error significantly improves estimation and prediction accuracy. [ABSTRACT FROM AUTHOR]

NAND flash memories, due to their several advantageous characteristics, have recently dominated the data storage industry and its global market. Currently, multi-level cell memories, in which each cell can store more than one bit of data resulting in higher data storage capacities, have gained a considerable amount of research interest. However, this comes at the cost of several limitations and increased performance degradation. Various studies have shown that among several error sources in multi-level cell memories, inter-cell interference is the most significant one. Therefore, to mitigate the devastating effect of the interference, simple, feasible, and yet efficient equalisation techniques become essential for achieving desired data reliability. In this study, first, a thorough analysis on deriving the distribution of the interference-free and interference-affected data is carried out. Then, novel low-complexity equalisation methods are proposed, and their beneficial complexity-performance trade-offs compared with the existing techniques are illustrated. Finally, simulation results are presented to show that the proposed algorithms considerably improve the error performance, while maintaining the low-complexity constraints. [ABSTRACT FROM AUTHOR]

Introduction. Obesity is increasingly common and is associated with an increased prevalence of cardiac arrhythmias. The aim of this study was to see whether in obesity there is proarrhythmic gene expression of ventricular ion channels and related molecules. Methods and Results. Rats were fed on a high-fat diet and compared to control rats on a normal diet (n=8). After 8 weeks, rats on the high-fat diet showed significantly greater weight gain and higher adiposity. Left ventricle samples were removed at 8 weeks and mRNA expression of ion channels and other molecules was measured using qPCR. Obese rats had significant upregulation of Cav1.2, HCN4, Kir2.1, RYR2, NCX1, SERCA2a, and RYR2 mRNA and downregulation of ERG mRNA. In the case of HCN4, it was confirmed that there was a significant increase in protein expression. The potential effects of the mRNA changes on the ventricular action potential and intracellular Ca2+ transient were predicted using computer modelling. Modelling predicted prolongation of the ventricular action potential and an increase in the intracellular Ca2+ transient, both of which would be expected to be arrhythmogenic. Conclusion. High-fat diet causing obesity results in arrhythmogenic cardiac gene expression of ion channels and related molecules. [ABSTRACT FROM AUTHOR]

We demonstrate RF arbitrary waveform generation based on microwave photonic filtering. We use four-wave mixing in a silicon nanowire to increase the number of taps in an N-tap microwave photonic filter (MPF). Using a programmable optical filter, we can control the tap weights and, hence, the MPF response and corresponding generated waveform. We show uniform and apodized waveforms with four taps and seven taps with tunable central frequencies. [ABSTRACT FROM PUBLISHER]

Our patient presented to a large university teaching hospital with a history of light-headedness, falls and multiple cerebrovascular ischaemic events. This caused a right sided hemiplegia and the patient experienced significant functional limitation. Extensive investigations were carried out to exclude any causative factors such as carotid artery disease and the patient had all identifiable cardiovascular risk factors identified and modified. No significant pathology was found and a referral was made to the cardiology service. Transthoracic echocardiography revealed a complex type 3 perforate 'pepper pot' atrial septal aneurysm with associated thrombus. The patient was commenced on warfarin and appropriate rate limiting medication. After discussion of all interventional modalities, the patient opted for conservative management. [ABSTRACT FROM AUTHOR]

Background. We present the case of a 35-year-old gentleman who presented with an aggressive cardiomyopathy with normal coronary arteries. He was later diagnosed with systemic lupus-related cardiomyopathy. Methods. We undertook an extensive review of the literature regarding cardiac manifestations of lupus and used over 100 journals to identify the key points in pathology, diagnosis, and treatment. Results. We have shown that cardiac lupus can be rapidly progressive and, unless treated early, can have severe consequences. The predominant pathologies are immune complex and accelerated atherosclerosis drive. Treatment comprised of high-level immunosuppression. [ABSTRACT FROM AUTHOR]

Background and aims Methods Results Conclusion Methods for femoral venous haemostasis following electrophysiology (EP) procedures include manual compression (MC) and suture‐based techniques such as a figure‐of‐eight suture secured with a hand‐tied knot (Fo8HT) or a modified figure‐of‐eight suture secured with a 3‐way stopcock (Fo8MOD). We hypothesised that short‐term bleeding outcomes using the Fo8MOD approach would be superior to MC. We additionally compared outcomes between Fo8MOD and Fo8HT approaches.We studied consecutive patients undergoing EP procedures at our institution between March and December 2023. Patients were categorised into three haemostasis groups: MC, Fo8HT and Fo8MOD. Access site complications were classified as major (requiring intervention or blood transfusion, delaying discharge or resulting in death) or minor (bleeding/haematoma requiring additional compression).1089 patients were included: MC 718 (65.9%); Fo8HT 105 (9.6%); Fo8MOD 266 (24.4%). Procedures were most commonly for atrial fibrillation (52.4%), atrial flutter (10.9%), and atrioventricular nodal re‐entrant tachycardia (10.1%). In patients receiving periprocedural anticoagulation (865, 79.4%), Fo8MOD associated with fewer complications than MC or Fo8HT (major: MC 2.2%, Fo8HT 6.0%, Fo8MOD 0.8%, p = .01; minor: MC 16.5%, Fo8HT 12.0%, Fo8MOD 7.4%, p = .002). In patients not receiving periprocedural anticoagulation, complications did not differ between haemostasis methods (total major and minor complications 5.8%, p = .729 for between groups rates). On multivariable logistic regression, Fo8MOD was associated with a significantly lower risk of access site complications (OR 0.29 [95% CI 0.17–0.48], p < .001), whilst intraprocedural heparinisation (OR 5.25 [2.88–9.69], p < .001) and larger maximal sheath size (OR 1.06 [1.00–1.11], p = .04) were associated with a higher risk of complications.Femoral haemostasis with Fo8MOD associates with fewer access site complications than MC and Fo8HT following EP procedures that need periprocedural anticoagulation. [ABSTRACT FROM AUTHOR]

Effusive-constrictive pericarditis (ECP) is a rare condition that may prove fatal without appropriate treatment. In ECP, there is concomitant existence of a pericardial effusion and C P, that together lead to impaired cardiac filling. Therapeutic pericardiocentesis only addresses part of the problem; surgical pericardiectomy may be required to relieve the constrictive element. Imaging in ECP characteristically demonstrates calcification or thickening of the pericardium. The authors describe a case of ECP were a number of imaging modalities (including echocardiography, cardiac magnetic resonance and CT) did not identify overt pericardial disease. The patient underwent surgical pericardiectomy that led to a rapid resolution of symptoms and full recovery. Histopathological analysis of the pericardial biopsy indicated a non-specific pericardial fibrosis, in keeping with the final diagnosis of ECP. [ABSTRACT FROM AUTHOR]

In Multi-Level Cell (MLC) memories, multiple bits of information are packed within the cell to enable higher capacity and lower cost of manufacturing compared to those of the single-level cell flash. However, because of heavy information packing, MLC memories suffer from several error sources including inter-cell interference, retention error, and random telegraph noise which make their lifetime shorter. Having so many error sources that are statistically hard to characterize makes it challenging to properly derive the underlying probability distribution of the sensed threshold voltage, which is vital for finding optimal decision rules to secure better detection performance and hence better lifetime. Although several recent works have already considered this problem, they mostly recourse to few loose assumptions that are far from being realistic. In this study, a more comprehensive/general analysis is conducted to derive the probability density function of the final sensed voltage, and through realistic simplifications, closed form expressions are presented. Extensive computer simulations corroborate the accuracy of the derived analytical expressions, and we think they shall be essential for accurately estimating the reliability and the overall lifetime of modern MLC memories. [ABSTRACT FROM AUTHOR]

Objective: Atrial fibrillation (AF) ablation services were significantly affected by the COVID-19 pandemic. We aimed to evaluate a symptom-based clinician prioritisation scheme for waiting list management compared with patient-completed quality of life (QoL) scores. We also sought to understand factors influencing QoL, particularly the impact of COVID-19, on patients awaiting AF ablation, via a bespoke questionnaire., Methods: Patients awaiting AF ablation were sent two QoL questionnaires (Atrial Fibrillation Effect on QualiTy of Life (AFEQT) and EuroQol 5D (EQ5D-5L)) and the bespoke questionnaire. At a separate time point, patients were categorised as C1-urgent, C2-priority or C3-routine by their cardiologist based on review of clinic letters., Results: There were 118 patients included with priority categorisation available for 86 patients. Median AFEQT scores were lower in C2 (30.4; 17.2-51.9) vs C3 patients (56.5; 32.1-74.1; p<0.01). Unplanned admission occurred in 3 patients in C3 with AFEQT scores of <40. Although 65 patients had AF symptoms during the pandemic, 43.1% did not seek help where they ordinarily would have. An exercise frequency of ≥3-4 times a week was associated with higher AFEQT (56.5; 41.2-74.1; p<0.001) and EQ5D (0.84; 0.74-0.88; p<0.0001) scores., Conclusion: The QoL of patients awaiting AF ablation is impaired and AFEQT helps to identify patients at risk of admission, over and above physician assessment. COVID-19 influenced patients seeking medical attention with symptomatic AF when they normally would. Regular exercise is associated with better QoL in patients awaiting AF ablation., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2022. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Background: Heart type fatty acid protein (HFABP) is a cytosolic protein released early after acute coronary syndrome (ACS) even in the absence of myocardial necrosis., Objectives: The purpose of this systematic review was to determine whether HFABP levels in patients with suspected, or confirmed ACS, improve risk stratification when added to established means of risk assessment., Methods: We searched Medline, Pubmed and Embase databases from inception to July 2015 to identify prospective studies with suspected or confirmed ACS, who had HFABP measured during the index admission with at least 1 month follow up data. A prognostic event was defined as allcause mortality or acute myocardial infarction (AMI)., Results: 7 trials providing data on 6935 patients fulfilled inclusion criteria. There were considerable differences between studies and this was manifest in variation in prognostic impact of elevated HFABP(Odds ratio range 1.2-15.2 for death). All studies demonstrated that HFABP provide unadjusted prognostic information and in only one study this was negated after adjusting for covariates. A combination of both negative troponin and normal HFABP conferred a very low event rate. No study evaluated the incremental value of HFABP beyond that of standard risk scores. Only one study used a high sensitive troponin assay., Conclusion: There was marked heterogeneity in prognostic impact of HFABP in ACS between studies reflecting differences in sampling times and population risk. Prospective studies of suspected ACS with early sampling of HFABP in the era of high sensitivity troponin are necessary to determine the clinical value of HFABP. HFABP should not currently be used clinically as a prognostic marker in patients with suspected ACS., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.)

Background and Aim of the Study: Q fever, caused by the rickettsia Coxiella burnetii, is a worldwide zoonotic disease with both acute and chronic manifestations. Endocarditis is the principal chronic manifestation. Q fever can easily be mistaken for degenerative valve disease due to its indolent presentation, the fastidious nature of the organism (routine cultures are negative), and the absence of a typical echocardiographic and macroscopic appearance for endocarditis. Prosthetic valve failure, with associated morbidity and mortality, have been described following unrecognized infections., Methods: Previous studies have documented the value of screening strategies in areas of high prevalence. Hence, a pilot study was conducted in a low-prevalence setting, in which 139 patients at two tertiary cardiac centers attending for elective valve replacement for degenerative valvular disease underwent testing for chronic Q fever infection by serological and molecular methods on blood and valve tissue., Results: Five patients (3.7%) had serological evidence of past exposure to Q fever (consistent with rates in the literature). None had evidence of chronic Q fever endocarditis. The cost of adopting a universal screening strategy is around £40,000 per case (if serology is used to screen patients prior to surgery)., Conclusions: Alternative and more cost-effective methods for identifying clinically quiet cases of chronic Q fever endocarditis are required.

We propose and validate experimentally a time-delay to intensity mapping process based on second-order optical integrators. This mapping provides dynamic control of the intensity modulation profile of a waveform based on a purely passive and linear process. In particular, we can realize linear intensity control by tuning the time-delay between two optical pulses launched into a second-order optical integrator. We suggest and experimentally prove the use of this mapping process for reconfigurable optical arbitrary waveform generation.

Disease registries, containing systematic records of cases, have for nearly 100 years been valuable in exploring and understanding various aspects of cardiology. This is particularly true for myocardial infarction, where such registries have provided both epidemiological and clinical information that was not readily available from randomised controlled trials in highly-selected populations. Registries, whether mandated or voluntary, prospective or retrospective in their analysis, have at their core a common study population and common data definitions. In this review we highlight how registries have diversified to offer information on epidemiology, risk modelling, quality assurance/improvement and original research-through data mining, transnational comparisons and the facilitation of enrolment in, and follow-up during registry-based randomised clinical trials.

In this paper, a photonic temporal integrator based on an active Fabry-Perot (F-P) cavity is proposed and theoretically investigated. The gain medium in the F-P cavity is a semiconductor optical amplifier (SOA) with high gain coefficient. Key feature of the proposed photonic integrator is that the length of integration time window is widely tunable and could be ideally extended to infinitely long when the injection current is approaching lasing condition. Based on an F-P cavity with practically feasible parameters, a photonic temporal integrator with an integration time window of 160 ns and an operation bandwidth of 180 GHz is achieved. The time-bandwidth product of this photonic temporal integrator is 28,800, which is about two-orders of magnitude higher than any previously reported results. Gain recovery effect has been also considered and analyzed for the impact on performance of the photonic integrator, followed by the simulation results of the impact of gain recovery.

A superluminal space-to-time mapping process is reported and numerically validated in grating-assisted (GA) co-directional couplers, e.g. fiber/waveguide long-period gratings (LPGs). We demonstrate that under weak-coupling conditions, the amplitude and phase of the grating complex apodization profile of a GA co-directional coupling device can be directly mapped into the device's temporal impulse response. In contrast to GA counter-directional couplers, this mapping occurs with a space-to-time scaling factor that is much higher than the propagation speed of light in vacuum. This phenomenon opens up a promising new avenue to overcome the fundamental time-resolution limitations of present in-fiber and on-chip optical waveform generation (shaping) and processing devices, which are intrinsically limited by the achievable spatial resolution of fabrication technologies. We numerically demonstrate the straightforward application of the phenomenon for synthesizing customized femtosecond-regime complex optical waveforms using readily feasible fiber LPG designs, e.g. with sub-centimeter resolutions.