Acute myocardial infarction with dynamic outflow obstruction precipitated by intra-aortic balloon counterpulsation.

Dynamic left ventricular outflow obstruction is associated with structural findings of asymmetric septal hypertrophy (less commonly concentric left ventricular hypertrophy) and systolic anterior motion of the anterior mitral valve leaflet. A patient who did not have this usual substrate for outflow obstruction presented with an acute anterior wall myocardial infarction complicated by congestive heart failure and cardiogenic shock. When an intra-aortic balloon pump was placed, the patient rapidly deteriorated and a dynamic outflow gradient was detected.