Ventricular septal defect due to myocardial infarction.

This dramatic and ominous complication usually occurs between the third and 14th day after acute myocardial infarction. The size of the defect varies from a pinhole to 4 cm. The sudden appearance of a loud systolic murmur, with or without a thrill, is often accompanied by rapid hemodynamic deterioration. This event must be differentiated from rupture of a papillary muscle with mitral regurgitation. If intensive medical treatment is ineffective, an attempt at surgical repair is indicated.