A patient without a history of heart disease was seen in our institution after 3-week history of progressive weakness, dyspnea, and orthopnea. Transthoracic echocardiography demonstrated inferoposterobasal akinesis and a left ventricular to right atrial shunt through the coronary sinus, which was confirmed on cardiac catheterization. This is only the second case reported in the English-language literature documenting this rare shunt after a myocardial infarction.