This is a report of a 63-year-old man who in the course of an inferior wall myocardial infarction developed a left ventricular aneurysm with communication to the right atrium and a haemodynamically significant intracardiac shunt. The unusual complication of a myocardial infarction was correctly diagnosed by transthoracic Doppler echocardiography, and later a successful surgical repair was done.