Prognostic significance of ventricular arrhythmia after repair of tetralogy of Fallot: a 12-year prospective study.

OBJECTIVE The aim of this study was to examine the prognostic significance of ventricular arrhythmia on the ambulatory electrocardiogram (ECG) after repair of tetralogy of Fallot. BACKGROUND Ventricular arrhythmia is common after repair of tetralogy of Fallot and has been proposed as the basis for late sudden death. The prognostic significance of ventricular arrhythmia on ambulatory ECG and the indications for therapy are uncertain. METHODS We performed a 48-h ambulatory ECG in 86 patients (3 to 45 years old [mean age 14 years]) after repair of tetralogy of Fallot. These patients were then followed up prospectively for 12 years. RESULTS At initial assessment in 1980, 47 patients (55%) had infrequent uniform ventricular extrasystoles (16 patients) or normal cardiac rhythm (31 patients) Group 1), and 39 patients (45%) had frequent uniform ventricular extrasystoles (> 30/h, 2 patients), complex extrasystole (30 patients) or nonsustained ventricular tachycardia (7 patients) (Group 2). There were no significant clinical or hemodynamic differences between the groups. In addition, nine patients had supraventricular tachyarrhythmia. Antiarrhythmic therapy was prescribed only for the 10 patients who had symptoms attributable to arrhythmia. There were two sudden deaths in Group 1 (4%) and one nonsudden death in Group 2 (2.5%). The absolute difference in mortality between groups was therefore 1.5% (95% confidence limits -6% to +9%), excluding a clinically significant difference in outcome. All but 1 of the 39 patients with complex ventricular arrhythmia are alive and well, including those with elevated (> or = 60 mm Hg) right ventricular pressure. CONCLUSIONS Nonsustained ventricular arrhythmia on ambulatory ECG does not identify patients at high risk for sudden death after repair of tetralogy of Fallot. There does not appear to be any advantage in potentially dangerous long-term antiarrhythmic therapy for asymptomatic postoperative patients.