This study was performed in 24 patients with tetralogy of Fallot in whom shunt operation was performed instead of total correction because of small left ventricular end-diastolic dimension. Left ventricular end-diastolic dimension was measured using M-mode and two-dimensional echocardiography pre- and at least one year postoperatively. There was no change in the postoperative left ventricular size in two patients. However, in the other 22 patients, the left ventricular dimension was increased to 70 to 103 percent of normal left ventricular size. According to the findings of this study, we can conclude that the patients in whom shunt operation was performed would most likely have an increased left ventricular size over time.