Ebstein Anomaly and the Range of Right-Sided Heart Defects

Abstract

Ebstein anomaly (EA) is a rare congenital heart defect characterized by an abnormal development of the tricuspid valve (TV) and ventricular myocardium. The TV is displaced downward into the right ventricle (RV), leading to an atrialized basal portion of the RV above the closure plane of the TV and an often hypoplastic functional RV. Common consequences include cyanosis, TV regurgitation, arrhythmias, and heart failure. Although primarily a valve defect, EA can be regarded as a cardiomyopathy as well. Coexistence of EA with other cardiomyopathies, including left ventricular non-compaction (LVNC), suggests a shared genetic or developmental basis. Diagnostic advancements such as echocardiography, cardiac magnetic resonance, and electrophysiological studies have greatly improved early identification, risk stratification, and management of EA. However, challenges persist, particularly in prenatal detection and differentiation of EA from other congenital TV malformations. Autopsy is fundamental in fatal EA cases to ascertain the diagnosis, understand the cause of death, and guide family counseling. Significant knowledge gaps remain concerning the exact etiology of EA. Future research should focus on unveiling the genetic/epigenetic pathways and environmental factors involved in the pathogenesis of this heart malformation. Filling these gaps will be essential for developing targeted and effective treatments and improving patient outcomes.