Percutaneous transluminal septal myocardial ablation (PTSMA) has been a useful therapeutic option for medically refractory patients with hypertrophic obstructive cardiomyopathy (HOCM). Multi-detector row computed tomography (MDCT) has enabled the non-invasive detection of coronary arteries. Therefore, we describe here a patient with HOCM who was treated by PTSMA, and the usefulness of MDCT for its greater certainty and safety for the management of PTSMA.