[Tetralogy of Fallot and aortic insufficiency]

Seven out of 348 cases of Fallot's tetralogy (2 %) referred over an eight year period were complicated by aortic incompetence (AI). The incidence of AI was much lower than in VSD (7.6 %), probably because of the prevailing haemodynamics: in high VSD, the left-to-right shunt may damage the aortic cusps whilst in Fallot's tetralogy the output of both ventricles is ejected directly into the aorta with no alteration of aortic valve function. In this series, infective endocarditis was the predominant cause of AI (3 cases); surgery had to be undertaken in the infectious phase in 2 cases. AI was coincidental in two other cases (rheumatic valvular disease and calcified bicuspid valve). In the remaining two cases, the role of increased aortic flow in late distension of the aortic valve ring is discussed. AI should be corrected in the same operative time as the Fallot's tetralogy. Late onset AI occurring after repair of Fallot's tetralogy should also be corrected; in this situation, it is often difficult to diagnose the origin of the diastolic murmur. Without surgery the prognosis is poor as the diastolic regurgitation occurs in a ventricle whose function is often already compromised.