Prognostic significance and natural history of left ventricular thrombi in patients with acute anterior myocardial infarction: A two-dimensional echocardiographic study

Abstract

Fifty-eight patients with transmural anterior myocardial infarction were prospectively studied with serial two-dimensional echocardiography to determine the clinical implications and prognostic significance of detection of left ventricular thrombus during acute myocardial infarction, the incidence of systemic embolization, and the possible occurrence of spontaneous regression of left ventricular thrombi. Patients were not treated with anticoagulants or platelet inhibitors during the acute phase of infarction or during follow-up. Two-dimensional echocardiograms were obtained within 24 hr of myocardial infarction, every 24 hr until day 5, every 48 hr until day 15, and every month for a follow-up of 2 to 11 months (mean 7), in the surviving patients; a total of 774 echocardiograms were obtained. Left ventricular thrombi were identified in 24 (41%) of the 58 study patients, and developed within 48 hr of infarction in 11 of these patients. Ten (91%) of the 11 patients with early thrombus formation died during hospitalization or during follow-up, while only two (15%) of the 13 who developed thrombus after 48 hr of infarction died (p < .005). Incidence of Killip class III or IV, total lactic dehydrogenase values, and extent of wall motion abnormalities were significantly higher in patients who developed a thrombus within 48 hr of infarction than in patients without thrombus. On the other hand, in patients who developed a thrombus after 48 hr of infarction, these parameters were not significantly different from those in patients who did not develop a thrombus. Spontaneous regression of thrombi was documented in three (20%) of the 15 patients who survived the acute phase of myocardial infarction. The incidence of clinically evident systemic embolic events was low: one of the 24 patients with left ventricular thrombus experienced transient ischemic attacks, and no embolic events were detected in patients without thrombus. We conclude that development of left ventricular thrombi within 2 days of acute anterior myocardial infarction occurs in patients with the most extensive infarcts and is predictive of high mortality. Our data also demonstrate that spontaneous regression of thrombi may occur. Finally, in our study patients, none of whom were treated with anticoagulants or platelet inhibitors, the incidence of clinically evident systemic embolic events was low.