Gopinathannair, Rakesh

Abstract Aims Syncope remains a diagnostic challenge despite advancements in testing and treatment. Cardiac syncope is an independent predictor of mortality and can be difficult to distinguish from other causes of transient loss of consciousness (TLOC). This paper explores whether artificial intelligence (AI) can improve the evaluation and management of patients with syncope. Methods and results We conducted a literature review and incorporated the opinions of experts in the fields of syncope and AI. The cause of TLOC is often unclear, hospitalization criteria are ambiguous, diagnostic tests are frequently non-informative, and assessments are costly. Patients are left with unanswered questions and limited guidance. Artificial intelligence (AI) has the potential to optimize syncope evaluation by processing large data sets, detecting imperceptible patterns, and assisting clinicians. However, AI has limitations, including errors, lack of human empathy, and uncertain clinical utility. Liability issues further complicate its integration. We present three viewpoints: (i) AI is crucial for advancing syncope management; (ii) AI can enhance the patient experience; and (iii) AI in syncope care is inevitable. Conclusion Artificial intelligence may improve syncope diagnosis and management, particularly through machine learning–based test interpretation and wearable device data. However, it has yet to surpass human clinical judgment in complex decision-making. Current challenges include gaps in understanding syncope mechanisms, AI interpretability, generalizability, and clinical integration. Standardized diagnostic approaches, real-world validation, and curated data sets are essential for progress. Artificial intelligence may enhance efficiency and communication but raises concerns regarding confidentiality, bias, inequities, and legal implications.

Background: Bilateral cardiac sympathetic denervation (BCSD) has shown promise in treating patients with nonischemic cardiomyopathy (NICM) suffering from refractory multifocal premature ventricular contractions (PVCs) and ventricular tachycardia (VT). Despite its growing use, the effectiveness of BCSD across different NICM etiologies has not been extensively studied. Research Question: How effective is BCSD across a variety of NICM etiologies? Goals: To evaluate the effectiveness of BCSD on left ventricular ejection fraction (LVEF) and PVC burden in patients with NICM. Methods: We conducted a subset analysis on a previous retrospective, observational study of NICM patients who underwent BCSD. Eight NICM etiologies were assessed. Results: 43 NICM patients underwent BCSD (mean age 52.3±14.7 years; 30% females). Overall, LVEF significantly improved (38.7±7.9% to 46.2±9.6%, p <0.001), and PVC burden (PVCb) significantly decreased (23.7±9.9% to 1.3±1%, p <0.001). A similar phenomenon was seen in idiopathic/dilated cardiomyopathy (CM) (LVEF: +8.7%, p <0.001; PVCb: -20.6%, p <0.001), post-viral CM (LVEF: +4.8%, p =0.2; PVCb: -24.2%, p <0.001), familial CM (LVEF: +10%; PVCb: +23.3%), giant cell CM (LVEF: +10%; PVCb: + 30.5%), and arrhythmogenic right ventricular CM (LVEF: +12.5%, p=0.09; PVCb -30.6%, p =0.001). Catecholaminergic polymorphic VT had a non-significant increase in LVEF (+5%, p=0.5) but a significant decrease in PVCb (-21.8%, p=0.02), whereas sarcoidosis had the opposite effect with significant increase in LVEF (LVEF: +13.4%, p=0.3) but non-significant decrease in PVCb (-16.1%, p=0.02). Lastly, hypertrophic CM remained unchanged in LVEF (30%) but PVCb decreased (-8%). Conclusion: BCSD demonstrates efficacy in improving LVEF and reducing PVCb across almost all NICM with refractory VT. However, a case-by-case evaluation is still needed for its use.

Introduction: Incident cardiac arrhythmias are common in hospitalized COVID-19 patients, but the impact of a second incident cardiac arrhythmia during hospitalization on clinical outcomes remain unclear. Hypothesis: The aim of this study was to assess the frequency and prognostic implications of a second incident arrhythmia in hospitalized COVID-19 patients over the pandemic course till vaccine availability. Methods: The multicenter COVID-RHYTHM Registry enrolled hospitalized COVID-19 patients from 3/8/2020 to 1/24/2021. Cardiac arrhythmia included documented atrial fibrillation (AF), atrial flutter (AFL), ventricular tachycardia (VT), severe sinus bradycardia (<40 bpm) or AV block. Outcomes were compared between patients with single vs. more than one incident arrhythmias adjusting for baseline variables. Results: Of 6299 hospitalized COVID-19 patients, 4398 had an had an incident cardiac arrhythmia during hospitalization, of which 822 (19%) had a second incident arrhythmia. Those with >1 incident arrhythmia had a higher baseline prevalence of heart failure, chronic kidney disease, coronary artery disease and sleep apnea (Table). Those with >1 incident arrhythmia had higher in-hospital mortality, need for ICU admission and need for rehab upon discharge. Length of stay was similar between the groups. Conclusions: In hospitalized COVID-19 patients with incident cardiac arrhythmias, a second incident arrhythmia during hospitalization was seen in 19%. Having >1 incident arrhythmia was associated with increased need for ICU admission and reduced survival.

Introduction: Cardiac arrhythmias are common in continuous flow left ventricular assist device (LVAD) recipients. The impact of axial vs. intrapericardial centrifugal LVAD pumps on arrhythmia incidence and associated clinical outcomes is unclear. Hypothesis: This multicenter study evaluated the impact of LVAD type (axial vs. centrifugal) on incidence of atrial and ventricular arrhythmias, ICD shocks and mortality in LVAD patients. Methods: Analysis was done on 536 patients who underwent LVAD implantation at 5 US centers from 2008 to 2016. The groups were divided based on their LVAD type (axial - HeartMate II [HMII, n=433] vs. centrifugal - HeartWare (HW, n=103). Baseline characteristics as well as incidence of post-LVAD atrial arrhythmias (PL-AA), ventricular arrhythmias (PL-VA) and ICD shocks were analyzed in these groups. Multivariable Cox Regression analysis was used to identify predictors of survival. Results: Of 536 patients, 433 had HMII axial LVAD and 103 had HW centrifugal VAD implant. At baseline, HMII group had more males, higher proportion of CRT-D and higher prevalence of AA (Table 1A). Left ventricular dimensions were similar between groups. During a median follow-up of 537 days of LVAD support, incidence of PL-VA and ICD shocks were significantly higher in the HM2 group compared to HW group whereas incidence of PL-AA was not significantly different (Table 1A). In multivariable Cox Regression analysis, LVAD indication was the only variable that predicted survival (Table 1B). Type of LVAD (axial vs. centrifugal) was not associated with survival (HMII vs. HW - HR 1.04, P=0.48). Conclusions: In this multi-center continuous flow LVAD cohort, axial HM2 VAD patients had a higher incidence of PL-VA and ICD shocks. Type of LVAD (axial vs. centrifugal) was not associated with survival.

AbstractCardiac physiologic pacing (CPP), encompassing cardiac resynchronization therapy (CRT) and conduction system pacing (CSP), has emerged as a pacing therapy strategy that may mitigate or prevent the development of heart failure (HF) in patients with ventricular dyssynchrony or pacing‐induced cardiomyopathy. This clinical practice guideline is intended to provide guidance on indications for CRT for HF therapy and CPP in patients with pacemaker indications or HF, patient selection, pre‐procedure evaluation and preparation, implant procedure management, follow‐up evaluation and optimization of CPP response, and use in pediatric populations. Gaps in knowledge, pointing to new directions for future research, are also identified.

AbstractIntroductionThe use of intracardiac echocardiography (ICE) is beneficial during the ablation of atrial fibrillation (AF). Evidence is conflicting regarding the clinical impact of using ICE on arrhythmia recurrence and mortality.MethodsPatients undergoing catheter ablation of AF during 2010–2017 were identified using the International Classification of Diseases‐9th and 10th Revision‐Clinical Modification (ICD‐9‐CM and ICD‐10‐CM) from the Nationwide Readmissions Database. Propensity matching was used to generate a control group. Patient demographics, Charlson comorbidity indexes, time from discharge to readmission, and the reason of readmission were extracted.ResultsFrom 2010 to 2017, 51 129 patients were included in the analysis out of which ICE was used in 8005 (15.7%) patients. The in‐hospital mortality at readmission was significantly higher in the patients without ICE use (2.9% vs. 1.7%, p = .02). The length of stay (LOS) at readmission was significantly higher in non‐ICE arm (median [interquartile range, IQR]: 3 [2–6] vs. 2 [3–5] days, p < .0001) with similar healthcare‐associated cost (HAC) in both the groups (median [IQR]: US$7507.3 [4057.8–15 474.2] vs. 7339.4 [4024.8–15 191.6], p = .43). Freedom from readmission was 12% higher (hazard ratio [HR] [95% confidence interval, CI]: 0.88 [0.83–0.94], p < .0001) with the use of ICE at 90‐day follow‐up, which was driven by 24% reduction in heart failure (HF) at follow‐up (HR [95% CI]: 0.76 [0.60–0.96], p = .02).ConclusionsICE use during AF ablation procedure reduces readmissions at 90 days by 12%, driven by a 24% decrease in HF‐related admissions. The non‐ICE arm showed a significantly higher LOS which offsets marginally higher HAC in the ICE arm.

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.

Oral anticoagulants (OACs) are medications commonly used in patients with atrial fibrillation and other cardiovascular conditions. Both warfarin and direct oral anticoagulants are susceptible to drug-drug interactions (DDIs). DDIs are an important cause of adverse drug reactions and exact a large toll on the health care system. DDI for warfarin mainly involve moderate to strong inhibitors/inducers of cytochrome P450 (CYP) 2C9, which is responsible for the elimination of the more potent S-isomer of warfarin. However, inhibitor/inducers of CYP3A4 and CYP1A2 may also cause DDI with warfarin. Recognition of these precipitating agents along with increased frequency of monitoring when these agents are initiated or discontinued will minimize the impact of warfarin DDI. Direct oral anticoagulants are mainly affected by medications strongly affecting the permeability glycoprotein (P-gp), and to a lesser extent, strong CYP3A4 inhibitors/inducers. Dabigatran and edoxaban are affected by P-gp modulation. Strong inducers of CYP3A4 or P-gp should be avoided in all patients taking direct oral anticoagulant unless previously proven to be otherwise safe. Simultaneous strong CYP3A4 and P-gp inhibitors should be avoided in patients taking apixaban and rivaroxaban. Concomitant antiplatelet/anticoagulant use confers additive risk for bleeding, but their combination is unavoidable in many cases. Minimizing duration of concomitant anticoagulant/antiplatelet therapy as indicated by evidence-based clinical guidelines is the best way to reduce the risk of bleeding.

Antiarrhythmic drugs (AAD) play an important role in the management of arrhythmias. Drug interactions involving AAD are common in clinical practice. As AADs have a narrow therapeutic window, both pharmacokinetic as well as pharmacodynamic interactions involving AAD can result in serious adverse drug reactions ranging from arrhythmia recurrence, failure of device-based therapy, and heart failure, to death. Pharmacokinetic drug interactions frequently involve the inhibition of key metabolic pathways, resulting in accumulation of a substrate drug. Additionally, over the past 2 decades, the P-gp (permeability glycoprotein) has been increasingly cited as a significant source of drug interactions. Pharmacodynamic drug interactions involving AADs commonly involve additive QT prolongation. Amiodarone, quinidine, and dofetilide are AADs with numerous and clinically significant drug interactions. Recent studies have also demonstrated increased morbidity and mortality with the use of digoxin and other AAD which interact with P-gp. QT prolongation is an important pharmacodynamic interaction involving mainly Vaughan-Williams class III AAD as many commonly used drug classes, such as macrolide antibiotics, fluoroquinolone antibiotics, antipsychotics, and antiemetics prolong the QT interval. Whenever possible, serious drug-drug interactions involving AAD should be avoided. If unavoidable, patients will require closer monitoring and the concomitant use of interacting agents should be minimized. Increasing awareness of drug interactions among clinicians will significantly improve patient safety for patients with arrhythmias.

Coronavirus disease 2019 (COVID-19) has presented substantial challenges to patient care and impacted healthcare delivery, including cardiac electrophysiology practice throughout the globe. Based upon the undetermined course and regional variability of the pandemic, there is uncertainty as to how and when to resume and deliver electrophysiology services for patients with arrhythmia. This joint document from representatives of the Heart Rhythm Society, American Heart Association, and American College of Cardiology seeks to provide guidance for clinicians and institutions reestablishing safe electrophysiological care. To achieve this aim, we address regional and local COVID-19 disease status, the role of viral screening and serological testing, return-to-work considerations for exposed or infected health care workers, risk stratification and management strategies based on COVID-19 disease burden, institutional preparedness for resumption of elective procedures, patient preparation and communication, prioritization of procedures, and development of outpatient and periprocedural care pathways.