Incidence and severity of chronic ventricular dysrhythmias after repair of tetralogy of Fallot.

A group of 72 patients who had undergone surgical correction of tetralogy of Fallot (TF) more than 5 years previously were evaluated for the presence and severity of ventricular dysrhythmias by treadmill exercise testing (TE) and 24-hour ambulatory ECG monitoring (AM). The results of rhythm evaluation were correlated with surgical and clinical data to determine characteristics which identified patients at risk for sudden death. Of the 72 patients, 30 (42%) manifested serious ventricular dysrhythmias on TE and/or AM. Four patients with documented ventricular dysrhythmias had subsequent cardiac arrest; an additional patient was admitted in ventricular tachycardia. Patients with ventricular dysrhythmias (group II) were found to be significantly older than patients without dysrhythmias (group I), both at the time of surgery and at the time of evaluation. The incidence of residual elevation of right ventricular systolic or diastolic pressure on postoperative catheterization did not differ between the two groups of patients. Ventricular extrasystoles on standard ECG were significantly more frequent in patients with documented ventricular dysrhythmias. Chronic serious ventricular dysrhythmias are very common in patients after TF repair. TE and AM should be an integral part of the long-term postoperative assessment in these patients.