The influence of pulmonary insufficiency on ventricular function following repair of tetralogy of Fallot. Evaluation using radionuclide ventriculography.

Long-standing pulmonary insufficiency after repair of tetralogy of Fallot may adversely affect ventricular function. We evaluated 20 patients at a mean of 9 years after repair by radionuclide ventriculography, 24 hour Holter monitoring, and M-mode echocardiography. The mean age at complete repair was 7.1 +/- 2.6 years. Patients were divided into groups as follows: Group I (eight patients), no clinical pulmonary insufficiency; Group II (12 patients), moderate to severe pulmonary insufficiency. Group II was further divided: Group IIa, transannular patch (six patients); Group IIb, no transannular patch (six patients). There was no difference between groups for age at operation, duration of follow-up, right ventricular pressure, or right ventricular-pulmonary arterial gradient. No patient had a residual shunt and all were in New York Heart Association Class I. Serious ventricular dysrhythmias occurred in 38% of Group I patients and 50% of Group II (p = NS). The echocardiographic ratio of right to left ventricular end-diastolic dimension was greater in patients with pulmonary insufficiency than in those without pulmonary insufficiency: 0.83 +/- 0.17 versus 0.55 +/- 0.15, p less than 0.01. Right ventricular ejection fraction was 0.39 +/- 0.08 in Group I and 0.27 +/- 0.07 in Group II, p less than 0.01. Left ventricular ejection fraction was 0.64 +/- 0.12 in Group I and 0.53 +/- 0.07 in Group II, p less than 0.02. Radionuclide angiography is a useful means of identifying right ventricular dysfunction following repair of tetralogy of Fallot. The dysfunction appears significantly worse in patients with pulmonary insufficiency.