The purpose of this investigation was to identify early left ventricular (LV) cineangiographic signs of myocardial damage and to study the evolution of the characteristic lesions in 126 chronic chagasic patients, divided into three groups. Group I patients had no clinical, ECG, or radiologic evidences of heart disease; 41% of them manifested apical or anterior apical asynergy, suggestive of early subclinical myocardial damage. Group II patients had abnormal ECG findings and no clinical signs of heart failure. Extensive asynergy, LV dilatation, decreased distensibility, and depressed contractility were found in 98% of these cases. Group III patients presented with congestive heart failure, a greatly dilated, hypokinetic LV chamber, and a 40% incidence of large apical aneurysms, 20% with thromboses within the LV. The performance of a left cineventriculogram in our chagasic patients enabled us to diagnose early myocardial damage and to detect potentially resectable lesions, such as ventricular aneurysms and apical thromboses.