Ventricular Arrhythmias in Adults With Congenital Heart Disease, Part II: JACC State-of-the-Art Review

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. Unlike acquired heart disease in which left ventricular pathology is prevalent, RV pathologies are crucial in the SCD pathogenesis in CHD patients. This review examines the mechanisms and management of SCD related to subpulmonary RV pathologies in CHD patients.

Right Ventricular Electrophysiology and Arrhythmias in Adults With Congenital Heart Disease: Scientific Basis for Management

Right ventricular (RV) dysfunction and arrhythmias are major concerns in adults with congenital heart disease (CHD). The relationship between RV dysfunction and arrhythmogenesis is bidirectional, with structural and electrical remodeling contributing to arrhythmia development and, conversely, arrhythmias exacerbating RV failure. In addition to an RV in the standard subpulmonary position failing because of pressure and/or volume overload, other phenotypes associated with RV dysfunction in CHD include transposition of the great arteries with a systemic (subaortic) RV and univentricular hearts with a predominant RV morphology. The RV is better suited for low-pressure workloads. When it supports the systemic circulation, the RV undergoes remodeling changes that promote arrhythmias, which can provoke a cycle of worsening dysfunction and arrhythmogenesis. Arrhythmias can worsen RV dysfunction by impairing hemodynamic stability, reducing cardiac output, provoking dyssynchrony, and inducing tachycardia-induced cardiomyopathy. Cellular mechanisms, including myocardial fibrosis, dysregulation of ion channels, and abnormal gap junction function, are central to this process, facilitating both re-entrant and triggered arrhythmias. Conduction disturbances, whether inherent or caused by fibrosis or pacing, compound these effects, aggravating both RV dysfunction and arrhythmia perpetuation. Management strategies must be comprehensive and include pre-emptive approaches to minimize arrhythmias, alongside early detection. Individualized therapies may include catheter ablation and cardiac implantable electronic devices, with treatment tailored to the specific RV phenotype and arrhythmia type. In this review we emphasize the importance of personalized interventions to prevent the vicious cycle of RV dysfunction and arrhythmias in CHD. Further research is essential to optimize therapeutic strategies and address care-limiting knowledge gaps.

Overlooked Ventricular Septal Defect Post-Myocardial Infarction and Coronary Artery Bypass Grafting

Ventricular septal defect (VSD) represents a severe complication that may manifest after a myocardial infarction (MI), typically occurring between 2 and 7 days later. Due to advancements in reperfusion management, the incidence of VSDs after MI has become very rare, occurring in approximately 0.2% of MIs. The current guidelines recommend urgent post-infarction VSD (PI-VSD) closure. We report a case of a patient with a VSD, which was diagnosed 2.5 years after MI. At the time of acute inferior MI, the patient was managed with primary percutaneous intervention in the culprit artery, and 1 month later coronary artery by-pass grafting (CABG) was completed. Twenty and thirty months after AMI patient presented with ventricular tachycardia (VT). Following the second VT episode patient was hospitalized for further examination. Echocardiography revealed the presence of VSD at the site of inferioseptal wall aneurysm. An ICD was implanted owing to recurrent malignant rhythm disorders. In conclusion, although the PI-VSD might have been overlooked and the patient missed the chance of concomitant CABG and VSD repair, this case has reached a 3-year survival, which appears to be the longest survival recorded in a medically treated patient with PI-VSD.

Editor-in-Chief's Top Picks From 2023

Each week, I record audio summaries for every paper in JACC, as well as an issue summary. This process has become a true labor of love due to the time they require, but I am motivated by the sheer number of listeners (16M+), and it has allowed me to familiarize myself with every paper that we publish. Thus, I have selected the top 100 papers (Original Investigations, Review Articles, Society Documents, and the Global Burden of Diseases) from distinct specialties each year. In addition to my personal choices, I have included papers that have been the most accessed or downloaded on our websites, as well as those selected by the JACC Editorial Board members. In order to present the full breadth of this important research in a consumable fashion, we will present these abstracts in this issue of JACC, as well as their Central Illustrations∗ and podcasts. The highlights comprise the following sections: Aorta; Basic and Translational Science; Cardiac Failure, Myocarditis, and Pericarditis; Cardiomyopathies and Genetics; Congenital Heart Disease; Coronary, Peripheral, and Structural Interventions; Coronavirus; Health Promotion and Preventive Cardiology; Imaging; Metabolic and Lipid Disorders; Neurovascular Disease and Dementia; Rhythm Disorders and Thromboembolism; and Valvular Heart Disease.1-104 ∗ To view the full manuscript, including the full-sized Central Illustration, please refer to the original publication in JACC.