Role of subpulmonary right ventricle in sudden cardiac death in adults with congenital heart disease.

Despite improved childhood survival of congenital heart disease (CHD) as a result of advances in management, late-onset sudden cardiac death (SCD) from malignant ventricular arrhythmias remains a leading cause of mortality in adults with CHD. Preventing SCD in these patients requires an understanding of the underlying pathophysiological mechanisms. Many CHD patients experience significant hemodynamic stress on the subpulmonary right ventricle (RV), leading to pathologic remodeling.

Risk Stratification for Sudden Cardiac Death in Repaired Tetralogy of Fallot.

There has been significant progress in the prevention of sudden cardiac death in repaired tetralogy of Fallot. Contemporary cohorts report greater survival attributable to improved surgical techniques, heart failure management, and proactive strategies for risk stratification and management of ventricular arrhythmias including defibrillator implantation and ablation technology. Over the last 25 years, our understanding of predictive risk factors has also improved from invasive and more limited measures to individualized risk prediction scores based on extensive demographic, imaging, electrophysiological, and functional data.

Incremental value of machine learning for risk prediction in tetralogy of Fallot.

Objective: Machine learning (ML) can facilitate prediction of major adverse cardiovascular events (MACEs) in repaired tetralogy of Fallot (rTOF). We sought to determine the incremental value of ML above expert clinical judgement for risk prediction in rTOF.

Methods: Adult congenital heart disease (ACHD) clinicians (≥10 years of experience) participated (one cardiac surgeon and four cardiologists (two paediatric and two adult cardiology trained) with expertise in heart failure (HF), electrophysiology, imaging and intervention).

Quantifying the impact of equity, diversity, and inclusion in electrophysiology: Training the first female electrophysiologists from Jamaica and Saint Lucia.

Background: Delivery of electrophysiology (EP) care in developing nations and underserviced populations faces many hurdles, including the lack of local expertise and knowledge creation. The West Indies has experienced a paucity of local EP expertise. The University of Toronto has undertaken a unique collaborative educational effort with the University of the West Indies.

Incidence and Clinical Predictors of Early and Late Complications of Implantable Cardioverter-Defibrillators in Adults With Congenital Heart Disease.

Background: The implantable cardioverter-defibrillator (ICD) has been proven to improve survival in adults with congenital heart disease (ACHD), but it is associated with a high rate of complications. We aimed to quantify the incidence of early (≤ 3 months; ECs) and late (> 3 months; LCs) complications in ACHD patients implanted with an ICD and to identify their clinical predictors.

Methods: We retrospectively reviewed 207 patients who had ICD follow-up at Toronto General Hospital from 1996 to 2019.

Automated Identification of Ventricular Tachycardia Ablation Targets: Multicenter Validation and Workflow Characterization.

Decrement evoked potentials (EPs) (DeEPs) constitute an accepted method to identify physiological ventricular tachycardia (VT) ablation targets without inducing VT. The feasibility of automated software (SW) in the detection of arrhythmogenic VT substrate has been documented. However, multicenter validation of automated SW and workflow has yet to be characterized.

An In-Silico model for evaluating the directional shock vectors in terminating and modulating rotors.

Out-of-hospital cardiac arrest (OHCA) accounts for a majority of mortality worldwide. Survivability from an OHCA highly depends on timely and effective defibrillation. Most of the OHCA cases are due to ventricular fibrillation (VF), a lethal form of cardiac arrhythmia.

The validity of current implantable cardioverter-defibrillator guidelines in a real-world population of adults with congenital heart disease: A single-center experience.

Aims: Sudden cardiac death (SCD) is a major cause of mortality in adults with congenital heart disease (ACHD). The role of implantable cardioverter-defibrillator (ICDs) in preventing SCD has been established, however, robust, clinical evidence-based guidelines are lacking in ACHD. The aim of this study was to evaluate the ICD guidelines in ACHD patients.

Catheter Ablation of Atrial Arrhythmias in Patients Post-Fontan.

Atrial arrhythmias are highly prevalent in the aging Fontan population and contribute importantly to morbidity and mortality. Although the most common arrhythmia is scar-based intra-atrial re-entrant tachycardia, various other arrhythmias may occur, including focal atrial tachycardia, atrioventricular node-dependent tachycardias, and atrial fibrillation. The type and prevalence of atrial arrhythmia is determined, in part, by the underlying congenital defect and variant of Fontan surgery.

The Role of Ablation in Prevention of Recurrent Implantable Cardioverter Defibrillator Shocks in Patients With Tetralogy of Fallot.

Background: Implantable cardioverter defibrillators (ICDs) are effective in preventing arrhythmic sudden cardiac death in patients with tetralogy of Fallot (TOF). Although ICD therapies for malignant ventricular arrhythmias can be life-saving, shocks could have deleterious consequences. Substrate-based ablation therapy has become the standard of care to prevent recurrent ICD shocks in patients with ischemic cardiomyopathy.

Postpacing interval is shorter than tachycardia cycle length-What's the mechanism?

A 33-year-old male who underwent surgery for Tetralogy of Fallot presented with atrial flutter. Electrophysiology study revealed concealed entrainment along the mid lateral right atrium with postpacing interval shorter than the tachycardia cycle length. Ablation at this site terminated the tachycardia.

Impact of Catheter Ablation for Atrial Arrhythmias on Repeat Cardioversion in Adults With Congenital Heart Disease.

Background: Atrial tachyarrhythmias (AAs) are the main source of morbidity and mortality in adult congenital heart disease (ACHD). Direct-current cardioversion (DCCV) is an effective method to acutely terminate AAs, but many patients require repeated DCCV. Little is known about the impact of radiofrequency catheter ablation (RFCA) of AAs on the incidence of repeated DCCV in patients with ACHD.

New developments in catheter ablation for patients with congenital heart disease.

: There are numerous challenges to catheter ablation in patients with congenital heart disease (CHD), including access to cardiac chambers, distorted anatomies, displaced conduction systems, multiple and/or complex arrhythmia substrates, and excessively thickened walls, or interposed material. : Herein, we review recent developments in catheter ablation strategies for patients with CHD that are helpful in addressing these challenges. : Remote magnetic navigation overcomes many challenges associated with vascular obstructions, chamber access, and catheter contact.

Role of amiodarone in the management of atrial arrhythmias in adult Fontan patients.

Background: Patients with Fontan circulation are known to be at high risk for developing atrial tachyarrhythmias (AAs). Our objective was to examine the efficacy and safety of amiodarone in the management of ATs in adult Fontan patients.

Methods: Primary outcomes of this single-centre, retrospective study included freedom from AAs and incidence of adverse effects of amiodarone on Fontan patients.