Risk of late sudden death after surgery for congenital heart disease.

Background: Sudden cardiac death is a significant concern among patients with congenital heart disease (CHD). We assessed the risk of remote sudden cardiac death after congenital heart surgery.

Methods: Patients undergoing congenital heart surgery before 21 years of age between 1982 and 2003 in the Pediatric Cardiac Care Consortium registry were linked to National Death Index data through 2019. Sudden cardiac death was defined as death associated with a cardiac arrest or ventricular fibrillation diagnosis code. Standardised mortality ratios relative to the general population were calculated using Centers for Disease Control and Prevention data.

Results: Among 30,566 patients discharged after their initial surgery, 2,718 deaths occurred over a median period of 23 years (IQR 19-27). Of 463 (17%) sudden cardiac deaths, the median age was 1.7 years (IQR 0.5-16.5). The mean incidence was 7 per 10,000 person-years (95% CI: 0.64-0.77), ranging from 2.7 for left-to-right shunt lesions to 37 for single-ventricle physiology. Cardiac comorbidities including heart failure (13.6%) and arrhythmias (7.1%) were more frequent among sudden cardiac death patients. Standard mortality ratios for sudden cardiac death were elevated across all CHD types, ranging from 8.0 (95% CI: 6.3-9.6) for left-to-right shunts to 107.7 (95% CI: 88.9-126.5) for single-ventricle physiology.

Conclusion: Sudden cardiac death risk is higher post-congenital heart surgery compared to the general population. Even patients with mild CHD are at risk, highlighting the need for long-term follow-up for all patients. Heart failure and arrhythmia prevalence suggest potential therapeutic targets to reduce sudden cardiac death risk.