PREVALENCE, RESOLUTION, AND DETERMINANTS OF LATE POTENTIALS IN PATIENTS WITH UNSTABLE ANGINA AND LEFT-VENTRICULAR WALL-MOTION ABNORMALITIES

Although transient myocardial ischemia such as exercise induced ischem ia has not been reported to be associated with the occurrence of late potentials, the association of late potentials with more profound isch emic damage, which is represented by reversible but prolonged left ven tricular wall motion abnormalities, has not been demonstrated. We pros pectively evaluated 37 unstable angina patients who had reversible but prolonged wall motion abnormalities after resolution of chest pain an d electrocardiogram (EGG) changes. Signal-averaged ECG (SAECG) and ech ocardiogram were recorded during the acute phase and before hospital d ischarge. Late potentials were present in 6 (16%) patients on the init ial SAECG recording and resolved in all 6 patients on the second recor ding before hospital discharge. Normalization of inferior left ventric ular wall motion abnormality and multivessel disease were observed mor e frequently in patients with late potentials on the initial recording than in patients without (p < 0.05 and p < 0.05, respectively). In co nclusion, late potentials were observed in patients who had reversible but prolonged wall motion abnormalities; these late potentials were r esolved with improvement of left ventricular wall motion abnormalities . These results suggest that myocardial ischemia with prolonged wall m otion abnormalities is a possible mechanism of the occurrence of late potentials.