Background: Sudden cardiac death (SCD) is a major cause of mortality in adults with congenital heart disease (CHD). The aim of this study was to determine the adult CHD population at risk of SCD and the clinical parameters associated with SCD.
Methods and results: We performed a multicenter case-control study. Patients who died suddenly as a result of proven or presumed arrhythmia were included (cases). For each case, 2 controls matched on diagnosis, type of surgical intervention, age, and gender were included. From 3 databases including 25 790 adults with CHD, 1189 deaths (5%) were identified, of whom 213 patients (19%) died suddenly. Arrhythmic death occurred in 171 of 1189 patients. The underlying cardiac lesions were mild, moderate, and severe CHD in 12%, 33%, and 55% of the SCD cases, respectively. Clinical variables associated with SCD were supraventricular tachycardia (odds ratio [OR], 3.5; 95% confidence interval [CI], 1.5-7.9; P=0.004), moderate to severe systemic ventricular dysfunction (OR, 3.4; 95% CI, 1.1-10.4; P=0.034), moderate to severe subpulmonary ventricular dysfunction (OR, 3.4; 95% CI, 1.1-10.2; P=0.030), increased QRS duration (OR, 1.34 [per 10-ms increase]; 95% CI, 1.10-1.34; P=0.008), and QT dispersion (OR, 1.22 [per 10-ms increase]; 95% CI, 1.22-1.48; P=0.008).
Conclusions: The clinical parameters found to be associated with SCD in adults with a broad spectrum of CHD, including systemic right ventricles, are similar to those in ischemic heart disease. Moreover, even those patients with mild cardiac lesions are potentially at risk for SCD. This highlights the need for further prospective studies as well as vigilant ongoing follow-up of the adult with CHD.