Life-threatening arrhythmias and RV dysfunction after surgical repair of tetralogy of Fallot. Comparison between transventricular and transatrial approaches.

BACKGROUND: Late postoperative arrhythmias and right ventricular dysfunction may occur after classic repair of tetralogy of Fallot. METHODS AND
RESULTS: During a mean follow-up of 8.9 years (range, 5 to 14 years), 24-hour ambulatory electrocardiographic studies were done in 107 patients after repair of tetralogy of Fallot. Radionuclide angiography was performed in 97, and 78 patients also underwent postoperative heart catheterization. The patients were divided into two groups: group A consisted of 71 patients aged 2 months to 61 years (mean, 6.8 years) in whom the right ventricular approach was used; group B included 36 patients aged 8 months to 39 years (mean, 7.9 years) whose repair was through the right atrium. A transannular patch was employed in 42 (59.2%) patients in group A and in 23 (63.9%) patients in group B. Eighteen patients were adults (> 18 years old) at the time of surgery: 13 (18.3%) in group A and 5 (13.8%) in group B. During a mean follow-up of 9.7 years, 57 (80.3%) group A patients were in New York Heart Association (NYHA) functional class I. Atrial flutter was present in 3 (4.2%) patients, and 28 (39.4%) had significant ventricular arrhythmias (> or = Lown grade 2). Postoperative heart catheterization showed good hemodynamic results in 36 of 54 group A patients studied (12 of whom had ventricular arrhythmias); moderate-to-severe pulmonary regurgitation was present in 14 (25.9%) patients; only 2 (3.7%) patients had right ventricular hypertension. On electrophysiological study, 8 of 28 (28.6%) patients in group A had inducible sustained ventricular tachycardia. Despite antiarrhythmic therapy, 2 of these patients died suddenly, presumably from ventricular arrhythmias. Two other late deaths in group A were caused by heart failure. During a mean follow-up of 7.2 years, 33 of 36 (91.7%) patients in group B were in NYHA functional class I. Atrial flutter was not found in any patient in this group. Only 1 (2.8%) patient, who had moderate-to-severe pulmonary regurgitation, had significant ventricular arrhythmias (> or = Lown grade 2). Postoperative catheterization showed good hemodynamic results in 20 of 24 patients; 3 (12.5%) had moderate-to-severe pulmonary regurgitation, and 1 (4.2%) patient had right ventricular hypertension. Sustained ventricular tachycardia could not be induced in any of the 5 adult patients who underwent electrophysiological studies. One late death (caused by endocarditis) occurred in group B.
CONCLUSIONS: The right atrial approach significantly reduced the risk of life-threatening ventricular arrhythmias after repair of tetralogy of Fallot (P < .001) without increasing the incidence of supraventricular arrhythmias. Right ventricular dysfunction and severe pulmonary regurgitation were also more prevalent (P < .01) when the right ventricular approach was used.