[Behavior of the ST segment, during isometric exercise, in chagasic patients with apical aneurysm of the left ventricle].

In order to study the ST-segment changes during isometric exercise (IE) we have reviewed the hemodynamic and cineangiographic protocols of 13 with Chaga's disease patients. On the basis of the electrocardiogram (EKG) and the left ventricular cineangiogram, the chagasic patients were divided in two groups. Chagas' group I: 6 patients with left ventricular apical aneurysm, Chagas' II: 7 patients with multiple left ventricular dyskinetic segment and occasional premature ventricular contractions. Fourteen subjects with normal left ventricular cineangiograms and normal EKG's were used as controls. The IE was performed by all chagasic and control subjects 31.9 +/- 18 (M +/- SD) months after the cardiac catheterization. The IE was performed at 25% of maximum voluntary capacity for 5 minutes. The precordial leads (V1-V6) were simultaneously recorded, in the standing position, immediately before and after the IE. The ST-segment changes were assessed by measuring the distance of the 'J point, of the ST-segment, to the baseline in three consecutive sinus beats. Immediately before the IE, 5 patients of Chagas' group I (86%) has ST-segment elevation (leadas V1-V2). In the control group, only 2 subjects (14%) had ST-segment elevation, (P less than 0.007). After IE, the control subjects "normalized" their ST-segment elevation, whereas it persisted elevated in the 5 Chagas' group I patients (P less than 0.003). These results suggest that in chagasic patients, the ST-segment changes observed during isometric exercise could be related to the presence of left ventricular apical aneurysm.