Long-term Follow-up of Intramyocardial Dissecting Hematomas Complicating Acute Myocardial Infarction

Intramyocardial dissecting hematoma is a form of subacute cardiac rupture complicating acute myocardial infarction. Initially contained within the myocardial wall, the hematoma may expand, rupture into adjacent structures, or spontaneously resolve. However, long-term follow-up is unknown because clinical and serial imaging data are lacking. The purpose of this study was to characterize the early and late myocardial wall changes after transmural myocardial infarction using serial ultrasound examinations of the infarct-related segments. Clinical, electrocardiographic, and echocardiographic features of 8 patients (7 men, mean age 59 years) who presented with acute myocardial infarction and echocardiographically documented intramyocardial dissecting hematoma were analyzed. All patients had precordial echocardiography and 6 underwent transesophageal echocardiography. Differentiating hematoma from trabeculations, thrombus, or pseudoaneurysm was done with contrast and color flow Doppler. Seven patients presented with S-T elevation in V1 to V4, and in 3 the elevation extended to V5, V6, I, and aVL. One patient presented with S-T elevation in II, III, aVF, V3R, and V4R. The most striking feature was persistent S-T elevation of more than 72 hours in all patients. Hematoma consisted of a cysticlike, echolucent cavity variable in size, adjacent to severely hypokinetic or dyskinetic infarct-related segments. Hematoma acoustic characteristics depended on time of evolution. Two patients underwent elective revascularization and the rest were medically treated. Two patients died and 6 were alive at the mean follow-up of 12 months. In conclusion, persistent S-T elevation is an important clue in suggesting intramyocardial dissecting hematoma, which is confirmed by its unique ultrasound appearance. Serial echocardiography is useful in determining its evolving nature, and may guide outcome.