Tunneled left anterior descending artery in a child with hypertrophic cardiomyopathy.

BACKGROUND: A 10-year-old boy presented with a history of severe angina on exertion. A two-dimensional echocardiogram showed mild asymmetric left ventricular (LV) hypertrophy localized to the interventricular septum, consistent with nonobstructive hypertrophic cardiomyopathy. A maximal treadmill exercise test was terminated early owing to marked downsloping of the ST-T segment on all precordial leads, associated with mild chest discomfort. Cardiac MRI and coronary angiography showed that the left anterior descending (LAD) artery was 'tunneled' from its origin to the junction of the middle and lower segments, causing systolic obliteration. PET showed diffusely blunted myocardial blood flow after dipyridamole infusion. A beating-heart technique was used to perform surgical mobilization of the superficial and lateral surfaces of the LAD artery. The patient was free from angina at 6 months after surgery. A repeat exercise test showed considerable improvement in exercise tolerance, which was associated with a marked decrease in ST-T changes on exertion. INVESTIGATIONS: Physical examination, laboratory tests, 12-lead electrocardiography, two-dimensional echocardiography, exercise testing, cardiac MRI, coronary angiography, PET, Holter electrocardiographic monitoring. DIAGNOSIS: Angina caused by extensive myocardial tunneling of the LAD artery in nonobstructive hypertrophic cardiomyopathy. MANAGEMENT: Bisoprolol therapy and surgical mobilization of the tunneled LAD artery.