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Background Medical emergency team (MET) calls allow unstable patients to be identified earlier and enables clinicians to institute timely management to ameliorate physiological stress. Sinus tachycardia is a common cause for triggering MET calls. In this study, outcome measures relating to patients who have a MET call for sinus tachycardia were analysed. Methods Two hundred and ninety-three consecutive patients who had MET calls as a result of sinus tachycardia were included in the study. Outcome measures assessed included inpatient mortality, duration of hospital stay, change in disposition of patient care, change in goals of care, and underlying aetiology. Comparison between medical and procedural patients was also performed. Results There were 154 patients in the medical group compared to 139 patients in the procedural group. Inpatient mortality was 13% and 6% respectively (p-value= 0.065). The duration of hospital stay was longer in the medical group (11 vs. 8 days, p-value= 0.295). Sepsis accounted for about 50% of MET call diagnoses in both groups. Around 20% of patients in both groups did not have a clear cause identified for the sinus tachycardia. About one-fifth of the patients in both groups were transferred to intensive care following the MET call (17% vs. 16%; p-value= 0.823). Conclusions Sinus tachycardia triggering MET call is not a benign condition. It not infrequently requires escalation of care and is associated with significant inpatient mortality. Clinicians should have a high index of suspicion for sepsis as the underlying cause. This article is protected by copyright. All rights reserved.

BACKGROUND: Arrhythmia is not uncommon among pulmonary hypertension (PH) population, and may be associated with disease severity. HYPOTHESIS: To investigate different spectrums and prevalence of arrhythmias in different clinical PH groups in Chinese population. METHODS: Patients diagnosed with PH between April 15, 2019, and August 2, 2021, were enrolled prospectively. The prevalence of different types of arrhythmias in PH patients were calculated. Logistic regression analyses were conducted to determine independent predictors for arrhythmia. RESULTS: One thousand patients were enrolled. The prevalence of any arrhythmia, sinus node dysfunction, sinus tachycardia, atrial fibrillation, atrial flutter, other types of atrial tachycardia, atrioventricular block, and ventricular tachycardia is 44.4%, 12.2%, 15.2%, 8.1%, 4.1%, 10.2%, 7.1%, and 2.5%. Logistic regression analyses revealed that older age and larger right ventricle (odds ratio: 1.111 and 1.095, p

BACKGROUND: Medical treatment of inappropriate sinus tachycardia (IST) remains suboptimal. Radiofrequency sinus node (RF-SN) ablation has poor success and higher complication rates. OBJECTIVE: We aimed to compare clinical outcomes of the novel SN sparing hybrid ablation technique with those of RF-SN modification for IST management. METHODS: This is a multicenter prospective registry comparing the SN sparing hybrid ablation strategy with RF-SN modification. The hybrid procedure was performed using an RF bipolar clamp, isolating superior vena cava/inferior vena cava with the creation of a lateral line across the crista terminalis while sparing the SN region (identified by endocardial 3-dimensional mapping). RF-SN modification was performed by endocardial and/or epicardial mapping and ablation at the site of earliest atrial activation. RESULTS: Of the 100 patients (hybrid ablation group, n = 50; RF-SN group, n = 50), 82% were women, and the mean age was 22.8 years. Normal sinus rhythm and rate were restored in all patients in the hybrid group (vs 84% in the RF-SN group; P = .006). Hybrid ablation was associated with significantly better improvement in mean daily heart rate and peak 6-minute walk heart rate compared with RF-SN ablation. The RF-SN group had a significantly higher rate of redo procedures (100% vs 8%; P < .001), phrenic nerve injury (14% vs 0%; P = .012), lower acute pericarditis (48% vs 92%; P < .0001), permanent pacemaker implantation (50% vs 4%; P < .0001) than did the hybrid ablation group. CONCLUSION: The novel sinus node sparing hybrid ablation procedure appears to be more efficacious and safer in patients with symptomatic drug-resistant IST with long-term durability than RF-SN ablation.

Persistent sinus tachycardia substantially increases the risk of cardiac death. Vagus nerve stimulation (VNS) is known to reduce the heart rate, and hence may be a non-pharmacological alternative for the management of persistent sinus tachycardia. To precisely regulate the heart rate using VNS, closed-loop control strategies are needed. Therefore, in this work, we developed two closed-loop VNS strategies using an in-silico model of the cardiovascular system. Both strategies employ a proportional-integral controller that operates on the current amplitude. While one control strategy continuously delivers stimulation pulses to the vagus nerve, the other applies bursts of stimuli in synchronization with the cardiac cycle. Both were evaluated in Langendorff-perfused rabbit hearts (n = 6) with intact vagal innervation. The controller performance was quantified by rise time (Tr), steady-state error (SSE), and percentual overshoot amplitude (%OS). In the ex-vivo setting, the cardiac-synchronized variant resulted in Tr = 10.7 ± 4.5 s, SSE = 12.7 ± 9.9 bpm and %OS = 5.1 ± 3.6% while continuous stimulation led to Tr = 10.2 ± 5.6 s, SSE = 10 ± 6.7 bpm and %OS = 3.2 ± 1.9%. Overall, both strategies produced a satisfying and reproducible performance, highlighting their potential use in persistent sinus tachycardia.

Sinus tachycardia (ST) is ubiquitous, but its presence outside of normal physiological triggers in otherwise healthy individuals remains a commonly encountered phenomenon in medical practice. In many cases, ST can be readily explained by a current medical condition that precipitates an increase in the sinus rate, but ST at rest without physiological triggers may also represent a spectrum of normal. In other cases, ST may not have an easily explainable cause but may represent serious underlying pathology and can be associated with intolerable symptoms. The classification of ST, consideration of possible etiologies, as well as the decisions of when and how to intervene can be difficult. ST can be classified as secondary to a specific, usually treatable, medical condition (eg, pulmonary embolism, anemia, infection, or hyperthyroidism) or be related to several incompletely defined conditions (eg, inappropriate ST, postural tachycardia syndrome, mast cell disorder, or post-COVID syndrome). While cardiologists and cardiac electrophysiologists often evaluate patients with symptoms associated with persistent or paroxysmal ST, an optimal approach remains uncertain. Due to the many possible conditions associated with ST, and an overlap in medical specialists who see these patients, the inclusion of experts in different fields is essential for a more comprehensive understanding. This article is unique in that it was composed by international experts in Neurology, Psychology, Autonomic Medicine, Allergy and Immunology, Exercise Physiology, Pulmonology and Critical Care Medicine, Endocrinology, Cardiology, and Cardiac Electrophysiology in the hope that it will facilitate a more complete understanding and thereby result in the better care of patients with ST.

Achieving the goal management of some arrhythmic syndromes can be challenging; medical treatment for inappropriate sinus tachycardia (IST) and postural orthostatic tachycardia syndrome (POTS) may be ineffective, necessitating multidisciplinary team treatment. Implantable defibrillator devices (ICDs), along with anti-arrhythmic drugs (AADs), remain the first-line treatment for primary electrical diseases that pose a risk of sudden cardiac death (SCD). Ablation of the arrhythmogenic substrate is not always suggested in patients with these pathologies, but it may be a valuable support for reducing arrhythmic burden, improving quality of life, and treating pathologies that are resistant to pharmacological treatment; however, this option is not often considered due to the potential risks associated with an invasive approach. Minimally invasive hybrid ablation in these syndromes, such as a hybrid thoracoscopic approach and the use of non-invasive mapping systems, reduces post-surgery complications and ensures the best possible outcome for the patient.Bei einigen arrhythmischen Syndromen kann das Erreichen des Therapieziels eine Herausforderung darstellen. Die medikamentöse Therapie bei inadäquater Sinustachykardie (IST) und posturalem orthostatischem Tachykardiesyndrom (POTS) ist gelegentlich ineffektiv und kann eine Behandlung im multidisziplinären Team erforderlich machen. Implantierbare Defibrillatoren (ICD [„implantable defibrillator device“]) und Antiarrhythmika (AAD [„anti-arrhythmic drug“]), bleiben die Erstlinientherapie für primäre Erkrankungen des elektrischen Reizleitungssystems, die mit einem Risiko für plötzlichen Herztod (SCD [„sudden cardiac death“]) einhergehen. Die Ablation des arrhythmogenen Substrats wird bei Patienten mit diesen Erkrankungen nicht immer empfohlen, kann aber eine wertvolle Unterstützung zur Reduktion der Arrhythmielast bieten, die Lebensqualität verbessern und eine Therapieoption bei gegenüber pharmakologischen Maßnahmen resistenten Pathologien darstellen. Jedoch wird dieser invasive Eingriff aufgrund der mit ihm einhergehenden möglichen Risiken nicht oft in Erwägung gezogen. Minimalinvasive Hybridablationsverfahren, wie beim thorakoskopischen Hybridzugang und dem Einsatz nichtinvasiver Mappingsysteme, reduzieren postoperative Komplikationen und stellen das bestmögliche Outcome für den Patienten sicher.

The electrocardiography (ECG) has short-term prognostic value in coronavirus disease 2019 (COVID-19), yet its ability to predict long-term mortality is unknown. This study aimed to elucidate the predictive role of initial ECG on long-term all-cause mortality in patients diagnosed with COVID-19.In this prospective cohort study, adults with COVID-19 who underwent ECG testing within a 17-hospital health system in Northeast Ohio and Florida between 03/2020-06/2020 were identified. An expert ECG reader analyzed all studies blinded to patient status. The associations of ECG characteristics with long-term all-cause mortality and intensive care unit (ICU) admission were assessed using Cox proportional hazards regression model and multivariable logistic regression models, respectively. Status of long-term mortality was adjudicated on 01/07/2022.Of 837 patients (median age 65 years, 51% female, 44% Black), 683 (81.6%) were hospitalized, 281 (33.6%) required ICU admission, 67 (8.0%) died in-hospital, and 206 (24.6%) died at final follow-up after a median (IQR) of 21 (9-103) days after ECG. Overall, 179 (20.7%) patients presented with sinus tachycardia, 12 (1.4%) with atrial flutter, and 45 (5.4%) with atrial fibrillation (AF). After multivariable adjustment, sinus tachycardia (E-value for HR=3.09, lower CI=2.2) and AF (E-value for HR=3.13, lower CI=2.03) each independently predicted all-cause mortality. At final follow-up, patients with AF had 64.5% probability of death compared with 20.5% for those with normal sinus rhythm (P.0001).Sinus tachycardia and AF on initial ECG strongly predict long-term all-cause mortality in COVID-19. The ECG can serve as a powerful long-term prognostic tool in COVID-19.

We sought to determine associations of early electrocardiogram (ECG) patterns with clinical deterioration (CD) within 5 days and with RV abnormality (abnlRV) by echocardiography in pulmonary embolism (PE).In this prospective, multicenter study of newly confirmed PE patients, early echocardiography and initial ECG were examined. Initial ECG patterns included lead-specific ST-segment elevation (STE) or depression (STD), T-wave inversion (TWI), supraventricular tachycardia (SVT), sinus tachycardia, and right bundle branch block as complete (cRBBB) or incomplete (iRBBB). We defined CD as respiratory failure, hypotension, dysrhythmia, cardiac arrest, escalated PE intervention, or death within 5 days. We calculated odds ratios (ORs) for CD and abnlRV with univariate and full multivariate models in the presence of other variables.Of 1676 patients, 1629 (97.2%) had both ECG and GDE; 415/1676 (24.7%) had CD, and 529/1629 (32.4%) had abnlRV. AbnlRV had an OR for CD of 4.25 (3.35, 5.38). By univariable analysis, the absence of abnormal ECG patterns had OR for CD and abnlRV of 0.34 (0.26, 0.44; p 0.001) and 0.24 (0.18, 0.31; p 0.001), respectively. By multivariable analyses, one ECG pattern had a significant OR for CD: SVT 2.87 (1.66, 5.00). Significant ORS for abnlRV were: TWI VSVT was an independent predictor of CD. TWI V

Purpose: To evaluate the effect of catheter directed thrombolysis (CDT) on heart rate (HR) in patients with sinus tachycardia and acute pulmonary embolism (PE). Methods: A retrospective chart review was performed for patients who underwent CDT with tPA for acute massive or submassive PE between 12/2009 and 2/2020. Included were patients who presented with tachycardia at the time of initiation of CDT. Patients with chronic PE, atrial fibrillation, beta blocker therapy, adjunctive endovascular therapy, systemic thrombolysis, or who expired before conclusion of CDT were excluded. HR was measured approximately every hour during CDT. Graphs were plotted of HR as a function of CDT duration. Two interventional radiologists identified the point of plateau (POP) on the graph where CDT had maximized its benefit in decreasing the patient’s HR. Discrepancies were adjudicated by a third interventional radiologist and the median of the 3 measurements was selected. The primary endpoint was the duration of CDT from initiation until the POP. Results: 48 patients were included (52.5 ± 14.7 years, 56.3% female). The POP occurred after 13.1 ± 6.1 hours, by which point HR had been reduced from 110 ± 9.2 bpm to 88 ± 10.6 bpm. Sinus tachycardia was not resolved in 10 patients even though they achieved maximal improvement in HR after 11.3 ± 6.7 hours. Conclusion: Patients presenting with sinus tachycardia related to acute PE achieved maximal, sustained reduction in heart rate from CDT, after approximately 13 hours of infusion. Patients who did not resolve their tachycardia by that point in time were unlikely to resolve it by the conclusion of CDT.

Introduction Supraventricular tachycardias (SVT) are often difficult to document due to their intermittent, short-lasting nature. Smartphone-based one-lead ECG monitors (sECG) were initially developed for the diagnosis of atrial fibrillation. No data have been published regarding their potential role in differentiating inappropiate sinus tachycardia (IST) from regular SVT. If cardiologists could distinguish IST from SVT in sECG, economic health care burden might be significantly reduced. Methods We prospectively recruited 75 consecutive patients with known SVT undergoing an EP study. In all patients, four ECG were recorded: a sECG during SVT and during sinus tachycardia and respective 12-lead ECG. Two experienced electrophysiologists were blinded to the diagnoses and separately evaluated all ECG. Results Three hundred individual ECG were recorded in 75 patients (47 female, age 50 ± 18 years, BMI 26 ± 5 kg/m2, 60 AVNRT, 15 AVRT). The electrophysiologists’ blinded interpretation of sECG recordings showed a sensitivity of 89% and a specificity of 91% for the detection of SVT (interobserver agreement κ = 0.76). In high-quality sECG recordings (68%), sensitivity rose to 95% with a specificity of 92% (interobserver agreement of κ = 0.91). Specificity increased to 96% when both electrophysiologists agreed on the diagnosis. Respective 12-lead ECG had a sensitivity of 100% and specificity of 98% for the detection of SVT. Conclusion A smartphone-based one-lead ECG monitor allows for differentiation of SVT from IST in about 90% of cases. These results should encourage cardiologists to integrate wearables into clinical practice, possibly reducing time to definitive diagnosis of an arrhythmia and unnecessary EP procedures. Graphical abstract A smartphone-based one lead ECG device (panel A) can be used reliably to differentiate supraventricular tachycardia (panel B) from inappropriate sinus tachycardia when compared to a simultaneously conducted gold-standard electrophysiology study (panels C, D).

Ivabradine is a unique agent that is distinct from beta-blockers and calcium channel blockers as it reduces heart rate without affecting myocardial contractility or vascular tone. Ivabradine is a use-dependent inhibitor targeting the sinoatrial node. It is approved for use in the United States as an adjunct therapy for heart rate reduction in patients with heart failure with reduced ejection fraction. In this scenario, ivabradine has demonstrated improved clinical outcomes due to reduction in heart failure readmissions. However, there has been conflicting evidence from prospective studies and randomized controlled trials for its use in stable ischemic heart disease regarding efficacy in symptom reduction and mortality benefit. Ivabradine may also play a role in the treatment of patients with inappropriate sinus tachycardia, who often cannot tolerate beta-blockers and/or calcium channel blockers. In this review, we highlight the evidence for the nuances of using ivabradine in heart failure, stable ischemic heart disease, and inappropriate sinus tachycardia to raise awareness for its vital role in the treatment of select populations.

Studies on the electrocardiogram findings in African pregnant women are limited. There is no information available in the literature on the electrocardiographic parameters of pregnant Angolan women.The aim of this study was to describe electrocardiographic findings in women with normal pregnancies in Bengo Province, Angola.This is a community-based study with a cross-sectional design conducted between September 2013 and March 2014 in Bengo. The study involved 114 black pregnant women, compared with a paired control group comprising of 120 black non-pregnant women, aged 15 to 42 years. A 12-lead electrocardiogram and a rhythm strip were recorded for all participants.In this study, the mean age was 26.2 ± 7.3 years. Comparing pregnant women vs. non-pregnant, we found the following mean values: Heart rate (83 bpm vs. 74 bpm, p .001), PR interval (146 ms vs. 151 ms, p = .034), QT interval (360 ms vs. 378 ms, p .001), QTIc Fridericia (398 ms vs. 403, p = .017), QTIc Framingham (399 ms vs. 404 ms, p = .013) and T-wave axis (34Pregnant Angolan women compared with controls, had several significantly higher values for heart rate, and significantly lower values of systolic blood pressure and diastolic blood pressure, PR interval, QT interval, QTc interval by Fridericia and Framingham and T-wave axis. Sinus tachycardia, T-wave inversion, and left ventricular hypertrophy, were the main electrocardiographic changes found.

The purpose of this review is to determine the causal mechanisms and treatment of inappropriate sinoatrial tachycardia (IST), defined as a non-physiological elevation in resting heart rate. IST is defined as a resting daytime sinus rate >100 beats/minute and an average 24-hour heart rate >90 beats/minute. Potential causal mechanisms include sympathetic receptor hypersensitivity, blunted parasympathetic tone, or enhanced intrinsic automaticity within the sinoatrial node (SAN) pacemaker-conduction complex. These anomalies may coexist in the same patient. Recent ex-vivo near-infrared transmural optical imaging of the SAN in human and animal hearts provides important insights into the functional and molecular features of this complex structure. In particular, it reveals the existence of preferential sinoatrial conduction pathways that ensure robust SAN activation with electrical conduction. The mechanism of IST is debated because even high-resolution electroanatomical mapping approaches cannot reveal intramural conduction in the 3-dimensional SAN complex. It may be secondary to enhanced automaticity, intranodal re-entry, or sinoatrial conduction pathway re-entry. Different pharmacological approaches can target these mechanisms. Long-acting β blockers in IST can act on both primarily increased automaticity and dysregulated autonomic system. Ivabradine targets sources of increased SAN automaticity. Conventional or hybrid ablation may target all the described abnormalities. This review provides a state-of-the-art overview of putative IST mechanisms. In conclusion, based on current knowledge, pharmacological and ablation approaches for IST, including the novel hybrid SAN sparing ablation, are discussed.

Background Persistent sinus tachycardia (ST) is frequently encountered during pregnancy and peripartum period and its etiology often remains elusive. We sought to examine the possible association between unexplained persistent ST and obstetric outcomes. Methods A case control study was conducted using chart review of women admitted in labor to one of 7 hospitals of Northwell Health between January 2015 to June 2021. After excluding women with structurally abnormal hearts, we identified patients with persistent ST during the peripartum period, defined as a heart rate of more than 100 bpm for more than 48 h. A control group was created by randomly subsampling those who did not meet the inclusion criteria for sinus tachycardia. Obstetric outcomes were measured as mother’s length of stay (LOS), pre-term labor (PTL), admission to the neonatal ICU (NICU), and whether she received cesarean-section (CS). Results Seventy-eight patients with persistent ST were identified, out of 141,769 women admitted for labor throughout the Northwell Health system. 23 patients with ST attributable to infection or hypovolemia from anemia requiring transfusion and 55 with unclear etiology were identified. After adjusting for age and parity, pregnant mothers with ST were 2.35 times more likely to have a CS than those without (95% CI: 1.46–3.81, p = 0.0005) and had 1.38 times the LOS (1.21- 1.56, p p = 0.008). Conclusion Among pregnant patients, patients with ST have higher rates of CS.This association is unclear, however potential mechanisms include catecholamine surge, indolent infection, hormonal fluctuations, and medications. More studies are needed to explore the mechanism of ST in pregnant woman to determine the clinical significance and appropriate management.

The purpose of the study was to evaluate the long-term outcomes of sinus node modification (SNM) in treating patients with severely symptomatic drug-refractory inappropriate sinus tachycardia (IST). The study included 39 patients with symptomatic drug-refractory IST who have undergone SNM at Saint Louis University Hospital. Data was reviewed retrospectively. Recurrence of symptoms was assessed at 3–6-month follow-up intervals. The mean age of our cohort was 31.5 ± 11. The mean HR at diagnosis was 135 ± 25.4 beats per minute (BPM). Thirty-seven of 39 (94.8%) patients had complete resolution of symptoms. Of these 37 patients, 16 required 1 SNM, 17 patients required 2 SNM, and 4 patients required 3 SNM in order to achieve complete symptom resolution. Mean HR post-procedure was 78.6 ± 12.3 BPM. Thirteen of 39 patients required rate control medication post-procedure, all of whom were prescribed beta-blockers. Patients were followed every 3 to 6 months with a mean follow-up duration of 62.3 ± 42.9 months from the patient’s last SNM procedure. Thirteen of those 37 patients (35.1%) developed intermittent symptomatic bradycardia requiring permanent pacemaker implantation. Two of the 39 patients had phrenic nerve injury, and 6 patients had post-procedure pericarditis. This study provides additional information to the limited dataset available in the literature and shows that SNM might provide patients with long-term symptomatic relief bearing in mind the potential increased risk for the need for permanent pacing.

Objective: Inappropriate sinus tachycardia (IST) is a syndrome characterized by an elevated resting heart rate with distressing symptoms and no secondary cause of sinus tachycardia. This study was conducted to evaluate both the prevalence of IST among symptomatic patients and heart rate variability (HRV) characteristics. Methods: The records of all consecutive symptomatic patients who had undergone 24-hour Holter monitoring between September 2015 and November 2016 at a single center were retrospectively evaluated. IST was defined as a 24-hour mean heart rate (HR) of ≥90 beats/minute and a resting HR of ≥100 beats/minute in the absence of any secondary cause of sinus tachycardia. All of the study data related to clinical characteristics, symptoms, concomitant diseases, and Holter electrocardiogram parameters were obtained from the electronic hospital records. A propensity age- and sex-matched control group was selected from a non-IST patient cohort. Results: A total of 1865 consecutive patients were evaluated and 32% were excluded due to an inadequate Holter recording period or insufficient quality, atrial fibrillation episodes, atrioventricular block, or >1% atrial or ventricular extrasystoles. Among 1265 patients with sinus rhythm, 4.98% (n=63) had IST. The IST patients were younger (39.6+-17.4 vs. 50.2+-17.2 years; p

Inappropriate sinus tachycardia (IST) is a clinical syndrome that generally affects young patients and is associated with distressing symptoms. Although the most common symptom is palpitations, it can be accompanied by a myriad of symptoms, including anxiety, dizziness, presyncope, and syncope. The pathogenesis of IST is not well understood and considered multifactorial, with autonomic dysfunction being the central abnormality. IST is a diagnosis of exclusion. Management presents a clinical challenge. The overall efficacy of lifestyle modifications and medical therapy may be limited. Recent advances in catheter and surgical sinus node sparing ablation techniques have led to improvement in outcomes. In addition, increased focus has led to development of multimodality team-based interventions to improve outcomes in this group of patients. In this review, we discuss the mechanistic basis of IST, review current approaches to diagnosis, and outline contemporary therapeutic approaches.

Inappropriate sinus tachycardia (IST) is a common observation in patients with post-COVID-19 syndrome (PCS) but has not yet been fully described to date. To investigate the prevalence and the mechanisms underlying IST in a prospective population of PCS patients. Consecutive patients admitted to the PCS Unit between June and December 2020 with a resting sinus rhythm rate ≥ 100 bpm were prospectively enrolled in this study and further examined by an orthostatic test, 2D echocardiography, 24-h ECG monitoring (heart rate variability was a surrogate for cardiac autonomic activity), quality-of-life and exercise capacity testing, and blood sampling. To assess cardiac autonomic function, a 2:1:1 comparative sub-analysis was conducted against both fully recovered patients with previous SARS-CoV-2 infection and individuals without prior SARS-CoV-2 infection. Among 200 PCS patients, 40 (20%) fulfilled the diagnostic criteria for IST (average age of 40.1 ± 10 years, 85% women, 83% mild COVID-19). No underlying structural heart disease, pro-inflammatory state, myocyte injury, or hypoxia were identified. IST was accompanied by a decrease in most heart rate variability parameters, especially those related to cardiovagal tone: pNN50 (cases 3.2 ± 3 vs. recovered 10.5 ± 8 vs. non-infected 17.3 ± 10; p

Inappropriate sinus tachycardia (IST) is a common observation in patients with post-COVID-19 syndrome (PCS) but has not yet been fully described to date. To investigate the prevalence and the mechanisms underlying IST in a prospective population of PCS patients. Consecutive patients admitted to the PCS Unit between June and December 2020 with a resting sinus rhythm rate ≥ 100 bpm were prospectively enrolled in this study and further examined by an orthostatic test, 2D echocardiography, 24-h ECG monitoring (heart rate variability was a surrogate for cardiac autonomic activity), quality-of-life and exercise capacity testing, and blood sampling. To assess cardiac autonomic function, a 2:1:1 comparative sub-analysis was conducted against both fully recovered patients with previous SARS-CoV-2 infection and individuals without prior SARS-CoV-2 infection. Among 200 PCS patients, 40 (20%) fulfilled the diagnostic criteria for IST (average age of 40.1 ± 10 years, 85% women, 83% mild COVID-19). No underlying structural heart disease, pro-inflammatory state, myocyte injury, or hypoxia were identified. IST was accompanied by a decrease in most heart rate variability parameters, especially those related to cardiovagal tone: pNN50 (cases 3.2 ± 3 vs. recovered 10.5 ± 8 vs. non-infected 17.3 ± 10; p p

Aims Inappropriate sinus tachycardia (IST) is a syndrome characterized by an elevated sinus rate unassociated with known physiological, pathological, or pharmacological causes. Despite published consensus documents, IST definitions appear to vary in the literature. In this study, we reviewed IST publications to evaluate IST definition variability and ascertain the degree to which consensus definitions are being adopted. Methods and results English-language articles in PubMed, Ovid MEDLINE, Ovid Embase, and Google Scholar published from 1 January 1970 to 1 June 2021 with the title terms ‘inappropriate sinus tachycardia,’ ‘non-paroxysmal sinus tachycardia,’ or ‘permanent sinus tachycardia’ were searched. In each, the IST definition used, qualifying characteristics, and publications cited to support each definition were recorded. We identified 138 publications meeting the search criteria. Inappropriate sinus tachycardia definitions were provided in 114 of 138 articles (83%). A majority of definitions (92/114, 81%) used distinct heart rate (HR) thresholds. Among these, the most common threshold was ≥100 beats per minute (BPM) (75/92, 82%), mainly measured at rest (54/92, 59%). Most definitions (47/92, 51%) included a second criterion to qualify for IST; these were most often an HR threshold of 90 BPM measured over 24 h by ambulatory electrocardiogram (37/47, 79%). Diagnosis of exclusion was a common criterion (75/92, 82%) but symptom status was not (41/92, 45%). The 2015 Heart Rhythm Society IST consensus was commonly cited but adopted in only 37% of definitions published after 2015. Conclusions Inappropriate sinus tachycardia definitions in current literature are inconsistent, and professional society consensus IST definitions have, to date, had limited impact.

Early identification of patients at risk of seizure after acute tramadol overdose is crucial. Yet, current evidence has been inconclusive regarding the factors associated with the seizure. There is a lack of study on the Chinese population and the value of electrocardiogram (ECG) in risk prognostication has not been fully evaluated. We aimed 1) to characterise the clinical presentations of isolated tramadol overdose in Hong Kong; 2) to study the frequency of seizure in such overdose and the factors associated with it using multivariable analysis; and 3) to explore the association between individual ECG parameters and seizure. This was a retrospective observational study on consecutive patients reported to the Hong Kong Poison Information Centre for tramadol overdose from 1 January 2008 to 30 November 2020. Duplicate cases or patients with an overdose of other co-ingestants were excluded. Univariate and multivariable logistic regression was performed to identify factors significantly associated with seizures in general and seizures that occurred after emergency department (ED) arrival. We identified 93 patients, including 54 women and 39 men, with a median age of 38 years during the study period. The majority was Chinese (90%) and only five patients had a history of seizure. The seizure occurred in 23 patients. Multivariable analysis showed that sinus tachycardia > 100 beats/min was significantly associated with a higher seizure risk (OR 27.95, 95% CI 2.22–351.84, p = 0.010) and age per 10 years increase was associated with a lower risk (OR 0.61; 95% CI 0.39–0.96, p = 0.033). No reliable predictors of seizure after ED arrival were identified. Many patients had ECG features consistent with sodium channel blockade but none of them was predictive of seizure. A younger age and sinus tachycardia > 100 beats/min were associated with a higher seizure risk after tramadol overdose but no reliable predictors of seizure after ED arrival were identified. Individual ECG parameters were not predictive of seizure.

Background The diagnosis of malignant pericardial effusion (MPE) is often associated with a poor prognosis, but due to the complexity and unspecific nature of MPE patients' clinical manifestations, imaging often performs an essential role in diagnosis and prognosis. Methods Patients diagnosed with MPE between 2013 and 2018 at one tumor hospital were included and followed up. The data covered the basic clinical features, imaging findings, treatments and prognosis of patients with MPE, and the factors that may have affected the prognosis were explored. Results A total of 216 patients with MPE were included with the median age of 60 years. The most common primary cancer type was lung cancer (73.6%), the most common symptom was dyspnea (62.9%) and the most common abnormal electrocardiogram finding was sinus tachycardia (42.1%). The median survival time of the 216 patients with MPE was 13.7 months. The factors affecting prognosis were echocardiographic fluid signs (HR = 2.37, P = 0.010), electrocardiographic evidence of sinus tachycardia (HR = 1.76, P = 0.006) and echocardiographic evidence of cardiac tamponade (HR = 3.33, P Conclusions MPE has complex clinical manifestations and an unsatisfactory prognosis. Echocardiographic fluid signs, electrocardiographic evidence of sinus tachycardia, and echocardiographic evidence of cardiac tamponade are independent risk factors affecting prognosis.

Inappropriate sinus tachycardia (IST) has been defined as a resting heart rate of >100 beats per minute and an average 24-hour heart rate >90 bpm with distressing symptoms resulting from the persistent tachycardia. IST is prevalent in 1% of the middle-aged population, mostly females. Rarely can elderly patients also present with IST. Possible mechanisms of IST include intrinsic sinus node abnormality, beta-adrenergic receptor stimulating autoantibody, beta-adrenergic receptor supersensitivity, muscarinic receptor autoantibody, or hyposensitivity, impaired baroreflex control, depressed efferent parasympathetic/vagal function, nociceptive stimulation, central autonomic overactivity, aberrant neurohumoral modulation, etc. Symptoms associated with IST are palpitations, chest pain, fatigue, shortness of breath, presyncope, and syncope. Despite these distressing symptoms, IST has not been associated with tachycardia-associated cardiomyopathy or increased major cardiovascular events. Various treatment options for patients with IST are ivabradine, beta-adrenergic blockers, calcium channel blockers, psychiatric evaluation, and exercise training. Although, endocardial radiofrequency ablation targeting the sinus node has been used as a treatment modality for otherwise treatment-refractory IST, the results have been dismal. The other modalities used for refractory IST treatment are endocardial modification of the sinus node using radiofrequency energy, combined endo and epicardial ablation of the sinus node, thoracoscopic epicardial ablation of the sinus node, sinus node sparing thoracoscopic and endocardial hybrid ablation. The goal of this review is to provide the readership with the pathophysiological basis of IST and its management options.

Objective The commonly held association of hyperthyroidism with sinus tachycardia and widened pulse pressure (PP) has not been reassessed in decades despite patients with hyperthyroidism in current practice not always present with these signs. The study objective was to assess prevalence and variability of sinus tachycardia and widened PP in present day among individuals with different degrees of hyperthyroidism. Methods Data was collected retrospectively from 248 adult patients in an outpatient setting with biochemical evidence of hyperthyroidism, recorded heart rate (HR) and blood pressure (BP) who were not treated with medications that can influence these parameters. Results Mean age was 42.0 ± 14.2 years with 66.9% being female. Median free thyroxine (fT4) level was 3.49 (IQR 2.42–4.58) ng/dL and thyroid stimulating hormone (TSH) 0.02 (IQR 0.01–0.03) mIU/L. Tachycardia, defined as HR >100 bpm, was present in 28.2%. In the lowest and highest fT4 quartiles, tachycardia was present in 16.4% and 38.7% respectively. Using logistic regression, tachycardia was associated with higher fT4 and diastolic BP. More lenient outcome of tachycardia with HR >90 bpm was seen in 47.2%. Widened PP, defined as >50 mmHg, was observed in 64.1% of patients and correlated with higher fT4 and BP. Conclusions Tachycardia is not a common feature of hyperthyroidism today. The relatively infrequent finding of tachycardia in this study compared to older studies may reflect differences in the way medicine is practiced today. The increased ordering of thyroid function tests most likely unmasked cases of mild or asymptomatic thyrotoxicosis. A widened PP was a more prevalent clinical finding in this study.

BACKGROUND: Inappropriate sinus tachycardia (IST) is an arrhythmic complication observed after coronary artery bypass graft (CABG) surgery which left untreated, commonly increases chances of postoperative stroke. The primary study objective was comparing effectiveness of beta blocker-metoprolol; a specific If blocker-ivabradine and its combination in patients who develop IST as a complication following CABG. MATERIALS AND METHODS: An open-labeled, investigator initiated, clinical study was conducted on 150 patients who developed IST (heart rate [HR] >100 beats/min) following elective CABG surgery. The patients were randomized into three treatment groups. Group I – received ivabradine (5 mg), Group II – metoprolol (25 mg), and Group III – ivabradine (5 mg) and metoprolol (25 mg). Treatment was given orally, twice a day for 7 days in all the three groups postoperatively. Primary endpoints were comparative effectiveness in HR and blood pressure reduction following treatment. RESULTS: IST was diagnosed by an electrocardiogram (12-lead) considering morphological features of P-wave and with 32% increase from baseline HR in all the three groups. Compared to IST arrthymic rate, HR was reduced in all groups following respective treatment (P = 0.05). Reduction in HR was significant (P < 0.05) in combination group followed by ivabradine which was significantly greater than metoprolol treated group. None of the treatments clinically changed the systolic, diastolic and mean blood pressure till discharge. No surgery/treatment-related complications were observed in any groups. CONCLUSION: Ivabradine stands as a pharmacological option for controlling HR and rhythm without associated side effects in postoperative CABG patients with IST.

In this paper we highlight the presence of tachycardia in post-acute COVID-19 syndrome by introducing a new label for this phenomenon-post-COVID-19 tachycardia syndrome-and argue that this constitutes a phenotype or sub-syndrome in post-acute COVID-19 syndrome. We also discuss epidemiology, putative mechanisms, treatment options, and future research directions in this novel clinical syndrome.