Wearable Cardioverter-Defibrillator in Adult Congenital Heart Disease: A Bridge to Decision, Recovery, and Advanced Therapies

Sudden cardiac death (SCD) remains a major cause of mortality among adults with congenital heart disease (ACHD). Risk stratification for malignant ventricular arrhythmias in this population is challenging because of the heterogeneity of anatomical substrates, lifelong haemodynamic changes, and the limited predictive accuracy of currently risk models. Furthermore, implantation of an implantable cardioverter-defibrillator (ICD) in ACHD patients is frequently complicated by anatomical constraints, limited venous access, and a significant burden of device-related complications, including infection involving prosthetic material. Several transient cardiac or systemic conditions-including haemodynamic deterioration, acquired myocardial disease, infections, inflammatory states, pregnancy, endocrine disturbances, or peri-procedural phases-may temporarily increase arrhythmic risk or impair ventricular function. In these scenarios, the indication for permanent ICD may be uncertain or premature. The wearable cardioverter-defibrillator (WCD) provides a non-invasive option for temporary protection against life-threatening ventricular arrhythmias while allowing time for clinical stabilization, diagnostic reassessment, and individualized decision-making. This review summarizes the pathophysiological rationale, available evidence, and potential clinical applications of WCD therapy in ACHD.