Transient mitral regurgitation due to mitral valve prolapse accompanied by systolic anterior motion of the mitral valve. A grade 4/6 systolic murmur, systolic anterior motion of the mitral valve (SAM), and severe mitral regurgitation (MR) documented by two-dimensional Doppler echocardiography developed suddenly on the structurally normal heart of a patient with idiopathic portal hypertension. The patient did not have signs of congestive heart failure and the aforementioned phenomenon disappeared completely when the patient was in hepatic failure. This could be explained by a change in circulating blood volume either by gastrointestinal hemorrhage or hepatic failure. 