Preventing sudden death in the adult with congenital heart disease

Adults with repaired congenital heart disease represent a complex and heterogeneous group of patients that are increasingly surviving beyond childhood. Patients have a variety of diagnoses that include specific structural anomalies, assorted physiologic derangements, and unique techniques for surgical repair. During long-term follow-up, even the most excellent surgical outcome may result in anatomic stenosis and insufficiency, cardiac rhythm disturbance, and myocardial dysfunction. Any of these abnormalities, alone or in combination, may result in significant morbidity and mortality. Sudden death is commonly due to a cardiac etiology and arrhythmias are frequently suspected to be the cause. Unfortunately, arrhythmias are difficult to predict and may be potentially lethal at their initial presentation. In addition, a wide spectrum of arrhythmias, both supraventricular and ventricular, are possible, depending on the specific diagnosis and type of repair performed. This review will focus primarily on arrhythmias as a cause of sudden cardiac death in this patient population. Particularly important considerations regarding arrhythmias in adults with congenital heart disease include the fact that supraventricular arrhythmias may be as lethal as ventricular arrhythmias, arrhythmia substrates develop in a unique manner when compared with other adult cohorts, and the electrophysiologic status of patients with repaired congenital heart disease must be considered together with the hemodynamic result.