Aortico-left ventricular tunnel: long-term outcome after surgical repair. Over a 14 year period, four children (three male, one female) underwent surgical correction of an aortico-left ventricular tunnel. All presented in infancy (age range 5 days to 9 months). The presenting feature was a systolic and diastolic murmur in all, one of whom developed heart failure within 2 weeks of presentation. In the first two patients, the echocardiographic findings were inconclusive and the diagnosis was confirmed at cardiac catheterization (at 10 and 23 months of age, respectively); the other two were diagnosed echocardiographically by two-dimensional and Doppler color flow imaging. All four patients underwent surgery by patch closure of the aortic end of the tunnel (three patients) or direct suture closure (one patient) and there were no deaths. The mean age at operation was 11 months. During a mean follow-up period of 71 months (range 2 to 157), three patients have clinical and echocardiographic evidence of trivial aortic valve regurgitation, which was noted in the immediate postoperative period in one and at early (less than 6 months) follow-up study in the other two. All are symptom-free, are taking no medications and are growing and developing normally. Aortico-left ventricular tunnel can be accurately diagnosed by echocardiography. In patients presenting in infancy, echocardiography also provides the necessary morphologic information to enable surgical correction without angiography. Early operation is associated with an excellent outcome, whereas repair at a later age is associated with a high incidence of residual aortic regurgitation requiring further surgery. 