Ventricular arrhythmias following balloon-expandable transcatheter pulmonary valve replacement in the native right ventricular outflow tract.

BACKGROUND: Ventricular arrhythmia incidence in children and adolescents undergoing transcatheter pulmonary valve replacement (TPVR) within the native right ventricular outflow tract (nRVOT) is unknown. We sought to describe the incidence, severity, and duration of ventricular arrhythmias and identify associated risk factors in this population. METHODS: This was a retrospective cohort study of 78 patients <21 years of age who underwent TPVR within the nRVOT. Patients were excluded for pre-existing ventricular arrhythmia or antiarrhythmic use. Study variables included surgical history, valve replacement indication, valve type/size, and ventricular arrhythmia. Univariable logistic regression models were used to evaluate factors associated with ventricular arrhythmias, followed by subset analyses. RESULTS: Nonsustained ventricular arrhythmia occurred in 26/78 patients (33.3%). The median age at the procedure was 10.3 years (interquartle range [IQR]: 6.5, 12.8). Compared with other nRVOT types, surgical repair with transannular patch was protective against ventricular arrhythmia incidence: odds ratio (OR): 0.35 (95% confidence interval [CI], 0.13-0.95). Patient weight, valve type/size, number of prestents, and degree of stent extension into the RVOT were not associated with ventricular arrhythmia occurrence. Beta blocker was started in 16/26 (61.5%) patients with ventricular arrhythmia. One additional patient was lost to follow-up. The median beta blocker duration was 46 days (IQR 42, 102). Beta blocker was discontinued in 10 patients by 8-week follow-up and in the remaining four by 9 months. CONCLUSIONS: Though common after balloon-expandable TPVR within the nRVOT, ventricular arrhythmias were benign and transient. Antiarrhythmic medications were successfully discontinued in the majority at 6- to 8-week follow-up, and in all patients by 20 months.

MRI in pediatric and congenital heart disease patients with CIEDs and epicardial or abandoned leads.

BACKGROUND: Heart Rhythm Society guidelines outlining magnetic resonance imaging (MRI) in patients with cardiac implantable electronic devices (CIEDs) excluded children and epicardial or abandoned leads due to theoretical risks of harm. Research investigating these risks is lacking. The primary objective of our study is to determine the incidence of adverse events to patients or CIEDs from MRI imaging. The secondary objective is to describe CIED-related artifact on MRI images. METHODS: A single-center retrospective review was performed on all patients with CIEDs who underwent 1.5 Tesla MRI between July 2007 and May 2019. We subdivided patients among four cohorts: (1) patients <18 years of age, (2) epicardial leads, (3) abandoned endocardial leads, and (4) abandoned epicardial leads. Descriptive statistics pre- and post-MRI and at follow-up within 1.5 years were conducted. RESULTS: Fifty-four MRIs were performed on 40 patients. Median age was 21.2 years (IQR 12.0-25.0). Eighteen (33%) MRIs contained abandoned leads; 20 (37%) contained epicardial leads. Three patients, one with abandoned epicardial leads and two with abandoned endocardial leads, experienced mild discomfort at the CIED site. One adult with endocardial leads experienced a pause in the heart rate while programmed in a nonpacing mode. No clinically important changes to CIED parameters occurred. Nine MRIs (17%), especially those with functional cardiac imaging, were uninterpretable due to image artifact. CONCLUSION: In this study, pediatric and adult CHD patients with CIEDs, many with epicardial or abandoned leads, underwent MRIs without clinically significant complications. In some, CIED artifact reduced cardiac MRI image quality due to CIED position.

A personalized approach to long QT syndrome.

PURPOSE OF REVIEW: Our purpose is to provide an update on the new clinical and genetic aspects of long QT syndrome (LQTS). LQTS is the most common channelopathy and a cause of syncope and sudden death in the young. Although there are 17 types of LQTS, most patients have types 1 or 2 which are due to mutations in KCNQ1 and KCNH2 (encoding for the cardiac potassium channels), and type 3 which is due to a mutation in SCN5A (encoding for the sodium channel). LQTS is characterized by incomplete penetrance and variable expressivity. Significant data exist concerning the common types of LQTS and include mutational location, biophysical function, gene-specific triggers, and disease modifiers that are known and help characterize the disease. RECENT FINDINGS: Recent studies support the use of ß-blockers in LQTS. Nadolol and propranolol are superior likely because of their sodium channel blocking effects. There are recent data supporting the use of ß-blockers in LQTS type 3 in which their use was once discouraged. There are increasing data that left cardiac sympathetic denervation is effective in LQTS and should be considered before an implantable cardioverter defibrillator is implanted. SUMMARY: LQTS is a model for effective collaboration between clinicians and basic scientists and between cardiologists and geneticists. Recent advances in the derivation of induced pluripotent stem cells from LQTS patients and creation of genetically engineered human models using clusters of regularly interspaced palindromic repeats (CRISPR/Cas9) will advance translational arrhythmia research and move us toward the goal of personalized medicine.