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 suspected hypertrophic obstructive cardiomyopathy in this patient. You wanted to make sure that your auscultatory findings are consistent with your suspicions. Of the following which bedside maneuver increases the intensity of murmur of this disorder?
