Implantable Cardioverter-Defibrillator therapy in adult congenital heart disease: insights from long-term follow-up at a tertiary center
I Ferreira Neves, L Magalhaes, M Coutinho Cruz, S Laranjo, G Portugal, S Santos, G Lourenco, T Branco Mano, T Rito, B Valente, P Silva Cunha, J D Martins, R Cruz Ferreira, L De Sousa, M Martins OliveiraAbstract
Background/Introduction
Sudden cardiac death (SCD) remains a major cause of mortality among adults with congenital heart disease (ACHD). However, evidence regarding the use and long-term outcomes of implantable cardioverter-defibrillators (ICDs) in this heterogeneous population is limited.
Purpose
We aimed to describe the clinical characteristics and long-term outcomes of ACHD patients with ICD therapy followed at our tertiary center.
Methods
We performed a retrospective analysis of consecutive ACHD patients who underwent ICD implantation in a single tertiary care center, between January 1994 and November 2025. Baseline characteristics, including cardiac anatomy, prior surgical history, and arrhythmic profile, were collected. Device data comprised indication for implantation, ICD type (single chamber, dual chamber, or CRT-D), and follow-up events, namely appropriate therapies, device-related complications, hospital admissions and mortality.
Results
Forty-six adult ACHD patients (mean age 42 ± 13.9 years) were included. The most frequent diagnoses were Tetralogy of Fallot (39.1%), D-transposition of the great arteries (10.9%), and shunt lesions such as VSD or ASD (8.7% each). Most patients were in NYHA class I (39.1%) or II (41.3%). ICD implantation was performed for primary prevention in 52.2% and secondary prevention in 47.8% of patients. The majority received single-chamber devices (69.6%), followed by dual-chamber (30.4%) and subcutaneous (13%). 10.9% of the transvenous systems were CRT-ICD (10.9%). The mean follow-up time was 7.2 (±6.4) years. Appropriate ICD therapies occurred more frequently in the secondary prevention group (54.5% vs. 37.5%, p = 0.25), while rates of inappropriate therapies were similar, and mostly due to sinus tachycardia and supraventricular arrythmias with heart rate >160 bpm (28.6% vs. 20.8%, p = 0.55). Within the subgroup implanted for primary prevention, appropriate ICD therapies were significantly more frequent among patients with class I indications compared to class II (p = 0.03, r = 0.45). In contrast, inappropriate therapies did not differ significantly between class I and class II indications (14.3% vs. 23.5%, p = 0.61).
Conclusions
ICD therapy in adults with congenital heart disease is associated with a substantial rate of appropriate interventions, but also with inappropriate therapies, suggesting a high arrhythmic burden and underscoring the need for careful risk stratification and follow-up.