Electrocardiographic changes as a marker of improved subendocardial ischemia in a patient with hypertrophic cardiomyopathy

Hypertrophic cardiomyopathy (HCM) patients sometimes develop subendocardial ischemia without coronary artery stenosis. We report a case of non-obstructive HCM, in which electrocardiographic changes were observed with improvement of subendocardial ischemia. A 76-year-old man presented with chest pain on exertion. The electrocardiogram revealed left ventricular (LV) hypertrophy with repolarization abnormalities. No coronary stenosis was found on computed tomography angiography, but thallium-201 exercise scintigraphy revealed transient LV cavity dilation after exercise, consistent with subendocardial ischemia. His chest symptoms disappeared after starting verapamil. Transient LV cavity dilation improved without a reduction in exercise tolerance, as did electrocardiographic abnormalities without any changes on echocardiography.