OBJECTIVEThe long-term success of intracardiac repair of tetralogy of Fallot is hampered by the occurrence of arrhythmias. The aim of the present study was to determine the incidence of arrhythmias after intracardiac repair of tetralogy of Fallot and their correlation with surgical and clinical findings.

METHODSThe study group consisted of 54 patients, 35 males and 19 females. They underwent repair at a mean age of 51 months (range 17 to 117 months). The median age at the time of study was 9.4 years (range 5 to 14 years), and the mean duration of follow-up was 4.3 years (range 2.8 to 9.0 years) after surgery. The follow-up study included routine ECG, 24 hour Holter, echocardiography and exercise testing.

RESULTSThe incidence of ventricular arrhythmia was 33 percent, and 1 patient had non-sustained ventricular tachycardia. All patients with elevated right ventricular pressure had ventricular arrhythmias, and 28% of patients with normal right ventricular pressure had ventricular arrhythmias (P < 0.05). 53% of patients had significant ventricular arrhythmias when the duration of cardiopulmonary bypass was > or = 90 minutes, as opposed to 23% when it was < 90 minutes (P < 0.05). There was no significant difference in prevalence of ventricular arrhythmias between mild pulmonary regurgitation and severe pulmonary regurgitation (21% vs 40%, P > 0.05). No significant difference was found in the incidence of ventricular arrhythmias between follow-up in five years and more than five years (32% vs 34%, P > 0.05). Age at surgery correlated with the prevalence of ventricular arrhythmias (r = -0.221, P < 0.05). Eight patients (15%) had supraventricular arrhythmias.

CONCLUSIONThe frequency of ventricular arrhythmias correlated with elevated right ventricular systolic pressure, the duration of cardiopulmonary bypass, and the age at surgery. No correlation was found between pulmonary regurgitation and the duration of follow-up. Exercise-induced frequent multiform premature ventricular complexes were associated with abnormal hemodynamic status and high risk of ventricular tachycardia.