Infarct Related Intramyocardial Dissection

Dissecting intramyocardial hematoma is a rare mechanical complication of acute myocardial infarction (MI). We describe four patients who sustained an acute inferior / inferoposterior MI, developed a new pansystolic murmur, and hemodynamically deteriorated in the first week following infarction. Two-dimensional echocardiography identified a complex rupture that dissected across the inferior portion of the interventricular septum, tunneled through right ventricular (RV) myocardium, and reentered the cavity of the RV. Color flow Doppler was particularly valuable in identifying the serpiginous course of the dissections as well as the entry and exit points. Cardiac catheterization demonstrated markedly increased right heart filling pressures, multivessel coronary artery disease, and evidence of the ventricular septal rupture. One patient died prior to surgery, and the other three expired within 24 hours of attempted surgical repair. We conclude that intramyocardial dissection is a complication of inferior / inferoposterior MI that can be rapidly diagnosed by echocardiography.