Effective disopyramide treatment in a boy with mid-ventricular hypertrophic obstructive cardiomyopathy.

A 14-year-old boy with mid-ventricular hypertrophic obstructive cardiomyopathy (MVHOCM) first presented at the age of 10 years with severe chest pain. Two-dimensional echocardiography disclosed marked hypertrophy at the mid-portion of the ventricular septum, and left ventriculography showed an hourglass appearance at systole. He was initially treated with propranolol, but the chest pain and dyspnea on exertion worsened at the age of 12 years. After disopyramide was started, the chest pain disappeared and the degree of the pressure gradient at the mid-ventricular level was reduced. There was also significant improvement on a 123I beta-methyliodophenyl pentadecaonic acid (BMIPP) myocardial scintigram.