Background: Arrhythmia is a major late complication in adults with repaired tetralogy of Fallot, although a large-scale study has not been carried out in Japan.
Methods and results: A nationwide multicenter study with 512 operative survivors was performed. Actuarial survival rate at 30 years (maximum follow-up) was 98.4%. Fifty-four patients (10.5%) had clinically important arrhythmias, including 23 patients with bradycardia caused by sick sinus syndrome or atrioventricular block (AVB). A patient with complete AVB (CAVB) without pacemaker implantation (PMI) died later. Two patients had sustained ventricular tachycardia (VT) and syncope was reported in 18 patients with ventricular arrhythmias (VA). Atrial tachyarrhythmias were observed in 13 patients. Older age at operation was a risk factor for atrial fibrillation/flutter, longer postoperative survival duration for VA, and QRS duration >120 ms for VT. Perimembranous ventricular septal defect was related to CAVB. Right ventricular outflow patch was not a risk factor. Importantly, 60% of the subjects had QRS duration <120 ms.
Conclusion: The prevalence of serious arrhythmias is low in Japanese TOF patients as compared with the results from Western countries. CAVB without PMI and VT are the major risk factors for late morbidity and mortality. The excellent result could be related to the narrow QRS after surgery.