A 22-year-old college wrestler comes for a sports physical examination. He tells you that he often feels excessively short of breath during practice and even has had chest pain that resolves with rest. He reports experiencing a syncopal episode 3 months ago while running a marathon. While taking the family history he tells you that his father died of ‘earlier-than-normal age’ sudden death. You send the patient for an echocardiogram, which reveals a hypertrophic heart, a thickened interventricular septum and a functional left ventricular outflow obstruction durings systole. You suspect hypertrophic obstructive cardiomyopathy in this young man. Of the following, where would you expect to hear the murmur with the loudest intensity?
