PROGNOSTIC-SIGNIFICANCE OF VENTRICULAR ARRHYTHMIA AFTER REPAIR OF TETRALOGY OF FALLOT - A 12-YEAR PROSPECTIVE-STUDY

Objectives. The aim of this study was to examine the prognostic signif icance of ventricular arrhythmia on the ambulatory electrocardiogram ( ECG) after repair of tetralogy of Fallot. Background. Ventricular arrh ythmia is common after repair of tetralogy of Fallot and has been prop osed as the basis for late sudden death. The prognostic significance o f ventricular arrhythmia on ambulatory ECG and the indications for the rapy 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 tetra logy of Fallot. These patients were then followed up prospectively for 12 years. Results. At initial assessment in 1980, 47 patients (55%) h ad infrequent uniform ventricular extrasystoles (16 patients) or norma l cardiac rhythm (31 patients) (Group 1), and 39 patients (45%) had fr equent 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 suprav entricular tachyarrhythmia. Antiarrhythmic therapy was prescribed only for the 10 patients who had symptoms attributable to arrhythmia. Ther e were two sudden deaths in Group 1 (4%) and one nonsudden death in Gr oup 2 (2.5%). The absolute difference in mortality between groups was therefore 1.5% (95% confidence limits -6% to + 9%), excluding a clinic ally significant difference in outcome. All but 1 of the 39 patients w ith complex ventricular arrhythmia are alive and well, including those with elevated (greater than or equal to 60 mm Hg) right ventricular p ressure. Conclusions. Nonsustained ventricular arrhythmia on ambulator y ECG does not identify patients at high risk for sudden death after r epair of tetralogy of Fallot. There does not appear to be any advantag e in potentially dangerous long-term antiarrhythmic therapy for asympt omatic postoperative patients.