Pseudoidiopathic hypertrophic subaortic stenosis in a patient with cardiac tamponade

A 53-year-old woman with a large pericardial effusion and tamponade presented with signs of IHSS including a grade 4/6 apical systolic murmur, severe SAM, early systolic aortic valve closure and a small hypercontractile left ventricle but at most borderline left ventricular hypertrophy. Following pericardiocentesis, the clinical and echocardiographic signs of subvalvular obstruction resolved completely. One year later the patient died of bronchial carcinoma and no evidence of hypertrophic cardiomyopathy was found at autopsy. Pericardial tamponade should be added to the list of possible causes of dynamic subvalvular obstruction in a structurally normal heart.