A Contemporary Assessment of the Risk for Sudden Cardiac Death in Patients With Congenital Heart Disease

Assessment of the risk for sudden cardiac death (SCD) after surgery for congenital heart disease (CHD) remains a difficult challenge. In the study of this problem, the focus has evolved from concern regarding late-onset heart block to a subsequent focus on ventricular and reentrant atrial arrhythmias, with the most recent emphasis on ventricular dysfunction and heart failure. Sudden cardiac death in CHD patients has been studied most extensively in tetralogy of Fallot. More than 30 risk factors have been proposed, with age at repair, QRS duration, right ventricular enlargement, and left ventricular dysfunction considered the most predictive risk factors. Additionally, SCD has been studied in patients with atrial repair for transposition of the great arteries, left heart obstructive lesions, and to a limited extent, patients with univentricular physiology. This review discusses current risk factors for SCD in CHD and the limited positive predictive value of any individual factor. The emphasis is on contemporary patients with CHD, who differ markedly from those who had repair of CHD decades earlier. This is characterized by complete repairs during the neonatal period, improved physiologic outcomes, and extended survival of patients with complex forms of CHD. Therefore, earlier data and conclusions may not be relevant to newer generations of patients with CHD. According to current perspectives, systemic ventricular dysfunction becomes a major risk factor beyond the age of 20 years. The first symptomatic arrhythmia may result in SCD, and defibrillators are increasingly implanted despite the lack of risk stratification criteria. The large number of potential risk factors and therapeutic options, in contrast to the low incidence of actual events, results in a difficult clinical challenge in the assessment of the risk for SCD in the individual patient with CHD.