Persistence of left atrial thrombus in patients with hypertrophic cardiomyopathy and atrial fibrillation.

Background: We recently demonstrated that patients with atrial fibrillation (AF) and hypertrophic cardiomyopathy (HCM) have an increased risk of left atrial (LA) thrombus. In this study, we aimed to evaluate thrombus management, thrombus persistence, and thromboembolic events for HCM and non-HCM patients with AF and LA thrombus.

Methods: From a cohort of 2,155 AF patients undergoing transesophageal echocardiography (TEE) for any indication, this study included 122 patients with LA thrombus (64 HCM patients and 58 non-HCM controls).

Fatal Cardiac Arrhythmias During Electronic Gaming in Patients With Genetically Mediated Heart Diseases.

Background: Recently, electronic gaming has been reported as a precipitant of life-threatening cardiac arrhythmias in susceptible individuals. However, the prevalence of cardiac events in genetic heart diseases (GHDs) in the setting of electronic gaming has not been established.

Objectives: In this study, we sought to define the prevalence of cardiac events occurring in the setting of electronic gaming in GHDs.

Personalized Care in Long QT Syndrome: Better Management, More Sports, and Fewer Devices.

Long QT Syndrome (LQTS) is a potentially life-threatening yet highly treatable inherited cardiac channelopathy. When evaluating these patients, it is important to consider patient-specific as well as genotype-specific factors in order to adequately encompass the many nuances to care that exist in its management. The tendency to follow a "one-size-fits-all" approach needs to be replaced by treatment strategies that embrace the unique considerations of the individual patient in the context of their genotype.

Cardiac fludeoxyglucose-18 positron emission tomography in genotype-positive arrhythmogenic cardiomyopathy.

Background: Myocardial inflammation contributes to the pathogenesis of arrhythmogenic cardiomyopathy (ACM), a clinically and genetically heterogenous disorder. Due to phenotypic overlap, some patients with genetic ACM may be evaluated for an underlying inflammatory cardiomyopathy. However, the cardiac fludeoxyglucose (FDG) positron emission tomography (PET) findings in ACM patients have not been elucidated.

Defining idiopathic ventricular fibrillation: A systematic review of diagnostic testing yield in apparently unexplained cardiac arrest.

Background: Idiopathic ventricular fibrillation (IVF) is diagnosed in patients with apparently unexplained cardiac arrest (UCA) after varying degrees of evaluation. This is largely due to the lack of a standardized approach to UCA.

Objective: We sought to develop an evidence-based diagnostic algorithm for IVF by systematically examining the yield of diagnostic testing in UCA probands.

Guidance on Minimizing Risk of Drug-Induced Ventricular Arrhythmia During Treatment of COVID-19: A Statement from the Canadian Heart Rhythm Society.

The COVID-19 pandemic has led to efforts at rapid investigation and application of drugs which may improve prognosis but for which safety and efficacy are not yet established. This document attempts to provide reasonable guidance for the use of antimicrobials which have uncertain benefit but may increase risk of QT interval prolongation and ventricular proarrhythmia, notably, chloroquine, hydroxychloroquine, azithromycin, and lopinavir/ritonavir. During the pandemic, efforts to reduce spread and minimize effects on health care resources mandate minimization of unnecessary medical procedures and testing.

The Effect of Shock Burden on Heart Failure and Mortality.

Background: Prior studies have demonstrated an association between appropriate implantable cardioverter defibrillator (ICD) shocks and mortality in clinical trials. The effect of shock burden on heart failure and mortality has not been previously studied in a large population-based cohort.

Methods: The cohort was derived using a comprehensive prospective ICD registry in the province of Nova Scotia with a mean follow-up of 4 ± 2.

Intentional nontherapy in long QT syndrome.

Background: International guidelines advise universal beta-blocker therapy as either a class I (symptomatic or QTc ≥470 ms) or class II (asymptomatic and QTc <470 ms) recommendation for treatment of long QT syndrome (LQTS).

Objective: The purpose of this study was to evaluate the outcomes of a highly selected cohort of patients with LQTS managed with an observation-only (intentional nontreatment) strategy.

Methods: The cohort was derived from a comprehensive retrospective registry of patients with LQTS.

Automated intraprocedural localization of origin of ventricular activation using patient-specific computed tomographic imaging.

Background: To facilitate catheter ablation of ventricular tachycardia (VT), we previously developed an automated method to identify sources of left ventricular (LV) activation in real time using 12-lead electrocardiography (ECG), the accuracy of which depends on acquisition of a complete electroanatomic (EA) map.

Objective: The purpose of this study was to assess the feasibility of using a registered cardiac computed tomogram (CT) rather than an EA map to permit real-time localization and avoid errors introduced by incomplete maps.

Methods: Before LV VT ablation, 10 patients underwent CT imaging and 3-dimensional reconstruction of the cardiac surface to create a triangle mesh surface, which was registered to the EA map during the procedure and imported into custom localization software.

Clinical utility of endomyocardial biopsies in the diagnosis of arrhythmogenic right ventricular cardiomyopathy in children.

Background: Histomorphometry of endomyocardial biopsies is one component of arrhythmogenic right ventricular cardiomyopathy (ARVC) diagnosis, although there is a need for stricter diagnostic criteria for this disease in pediatrics. The clinical utility of biopsy analysis as a component of ARVC diagnosis was evaluated in pediatric patients.

Methods: Histomorphometric analysis of fibrofatty infiltrate was completed on pediatric right ventricular endomyocardial biopsy samples.

Treatment of persistent ventricular tachycardia: Drugs or ablation?

Implantable cardioverter defibrillators (ICDs) reduce the mortality risk associated with recurrent ventricular tachycardia (VT) and can frequently terminate VT episodes painlessly, but do not prevent recurrent episodes. For patients with symptomatic recurrences, frequent asymptomatic recurrences, ICD shocks, or VT storm, most clinicians recommend strategies to suppress VT. The proarrhythmic mortality risk of antiarrhythmic drugs (AADs) may be mitigated by the presence of an ICD, but these medications are limited by high recurrence rates, and unfavorable side effect profiles.

Long-Term Arrhythmic and Nonarrhythmic Outcomes of Lamin A/C Mutation Carriers.

Background: Mutations in LMNA are variably expressed and may cause cardiomyopathy, atrioventricular block (AVB), or atrial arrhythmias (AAs) and ventricular arrhythmias (VA). Detailed natural history studies of LMNA-associated arrhythmic and nonarrhythmic outcomes are limited, and the prognostic significance of the index cardiac phenotype remains uncertain.

Objectives: This study sought to describe the arrhythmic and nonarrhythmic outcomes of LMNA mutation carriers and to assess the prognostic significance of the index cardiac phenotype.

Multicenter Experience With Catheter Ablation for Ventricular Tachycardia in Lamin A/C Cardiomyopathy.

Background: Lamin A/C (LMNA) cardiomyopathy is a genetic disease with a proclivity for ventricular arrhythmias. We describe the multicenter experience with percutaneous catheter ablation of sustained monomorphic ventricular tachycardia (VT) in LMNA cardiomyopathy.

Methods And Results: Twenty-five consecutive LMNA mutation patients from 4 centers were included (mean age, 55±9 years; ejection fraction, 34±12%; VT storm in 36%).

Catheter ablation for ventricular tachycardia in structural heart disease.

The management of ventricular tachyarrhythmias has changed significantly over the past several decades. The advent of readily available implantable cardioverter defibrillators (ICDs) has had the greatest effect, with important mortality effects in patients with ventricular tachycardia and structural heart disease. ICDs have been shown to reduce sudden death in patients with ischemic and nonischemic cardiomyopathies; evidence of adverse consequences of ICD shocks, however, is mounting.