Clinical findings are reported in 5 cases of anomalous left coronary artery originating from pulmonary trunk, with reference of ventricular function evaluated through echocardiographic and angio-haemodynamic methods. All patients were catheterized between 7 and 8 months of age. Left atrial and ventricular dilatation, diminished shortening of minor diameter and free wall thickness and septum normal values were obtained by echocardiography. Quantitative angiography of left ventricle demonstrated an elevation of end-diastolic volumes (mean values: 270% of predicted normal). The ejection phase indexes are diminished. The left ventricular mass/end-diastolic volume ratio was low in all cases. Myocardial imaging with thallium-201 demonstrated perfusion defect in lateral area of left ventricle in one patient. The electrocardiographic signs of myocardial necrosis support the diagnosis, and the echocardiographic and isotopic studies may contribute to it. The angio-haemodynamic method corroborate the diagnosis, and the myocardial pump function evaluation may help to decide the most appropriate treatment for this anomaly.