Arrhythmic Mitral Valve Prolapse: Risk Assessment and Management.

Arrhythmic mitral valve prolapse (MVP) has gained great interest recently because of the increasing recognition of its potential role in unexplained cardiac arrest. Although evidence has accumulated to show the association of arrhythmic MVP (AMVP) with sudden cardiac death (SCD), risk stratification and management remain unclear. Physicians are faced with the challenges of screening for AMVP among MVP patients and the dilemma of when and how to intervene to prevent SCD in these patients. In addition, there is little guidance to help approach MVP patients who present with an otherwise unexplained cardiac arrest to know whether MVP was the primary cause of cardiac arrest or just an innocent bystander. Herein we review the epidemiology and definition of AMVP, the risk and mechanisms of SCD, and summarize the clinical evidence behind risk markers of SCD and therapeutic interventions that could potentially prevent it. We also propose an algorithm that provides guidance as to how to screen for AMVP and what therapeutic interventions to use. Last, we propose a diagnostic algorithm for approaching patients with otherwise unexplained cardiac arrest who are shown to have MVP.

Atrial Arrhythmias in Clinically Manifest Cardiac Sarcoidosis: Incidence, Burden, Predictors, and Outcomes.

Background Recent data have suggested a substantial incidence of atrial arrhythmias (AAs) in cardiac sarcoidosis (CS). Our study aims were to first assess how often AAs are the presenting feature of previously undiagnosed CS. Second, we used prospective follow-up data from implanted devices to investigate AA incidence, burden, predictors, and response to immunosuppression. Methods and Results This project is a substudy of the CHASM-CS (Cardiac Sarcoidosis Multicenter Prospective Cohort Study; NCT01477359). Inclusion criteria were presentation with clinically manifest cardiac sarcoidosis, treatment-naive status, and implanted with a device that reported accurate AA burden. Data were collected at each device interrogation visit for all patients and all potential episodes of AA were adjudicated. For each intervisit period, the total AA burden was obtained. A total of 33 patients met the inclusion criteria (aged 56.1±7.7 years, 45.5% women). Only 1 patient had important AAs as a part of the initial CS presentation. During a median follow-up of 49.1 months, 11 of 33 patients (33.3%) had device-detected AAs, and only 2 (6.1%) had a clinically significant AA burden. Both patients had reduced burden after CS was successfully treated and there was no residual fluorodeoxyglucose uptake on positron emission tomography scan. Conclusions First, we found that AAs are a rare presenting feature of clinically manifest cardiac sarcoidosis. Second, AAs occurred in a minority of patients at follow-up; the burden was very low in most patients. Only 2 patients had clinically significant AA burden, and both had a reduction after CS was treated. Registration URL: https://www.clini​caltr​ials.gov; unique identifier NCT01477359.

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. We recommend that the risk of drug proarrhythmia be minimized by 1) discontinuing unnecessary medications that may also increase the QT interval, 2) identifying outpatients who are likely to be at low risk and do not need further testing (no history of prolonged QT interval, unexplained syncope, or family history of premature sudden cardiac death, no medications that may prolong the QT interval, and/or a previous known normal corrected QT interval [QTc]), and 3) performing baseline testing in hospitalized patients or those who may be at higher risk. If baseline electrocardiographic testing reveals a moderately prolonged QTc, optimization of medications and electrolytes may permit therapy. If the QTc is markedly prolonged, drugs that further prolong it should be avoided, or expert consultation may permit administration with mitigating precautions. These recommendations are made while there are no known effective treatments for COVID-19 and should be revisited when further data on efficacy and safety become available.

The echocardiographic assessment of the right ventricle in patients with arrhythmogenic right ventricular cardiomyopathy/dysplasia compared with athletes and matched controls.

BACKGROUND: There are discrepancies in the quantitative echocardiographic criteria for the right ventricle (RV) between the revised task force criteria (TFC) for Arrhythmogenic Right Ventricular Cardiomyopathy/Dysplasia (ARVC/D) and the guidelines for RV assessment endorsed by American Society of Echocardiography (ASE). Importantly, these criteria do not take into account potential adaptation of the RV to exercise. The goal of this study was to compare the revised TFC quantitative echocardiographic parameters in patients with ARVC/D, athletes and matched controls. METHODS: Echocardiographic parameters of the RV were retrospectively collected in patients who fulfilled the TFC for ARVC/D, an age- matched, sex-matched, and body surface area-matched control population, and athletes (defined as individuals who exercised for more than 7 hours per week). Patients with structural heart disease were excluded in the control and athlete groups. RESULTS: Twenty patients with ARVC/D, 11 athletes and 20 matched controls were included. There was no significant difference between ARVC/D patients and athletes with the exception of the parasternal long axis right ventricular outflow tract diameter. All parameters were significantly different between ARVC/D patients and the control group. Furthermore, when subjects were categorized into meeting 1 major revised TFC/abnormal ASE criteria or not, only ASE criteria were able to differentiate ARVC/D from control population. Both were unable to differentiate ARVC/D from athletes. CONCLUSIONS: Right ventricle quantitative echocardiographic criteria in the revised TFC are not specific for ARVC/D. Care should be taken in applying these criteria in athletes.