A 56-year-old male with hypertrophic obstructive cardiomyopathy complicated with medically refractory paroxysmal atrial fibrillation and congestive heart failure was treated with percutaneous transluminal septal myocardial ablation. The resting left ventricular outflow tract gradient decreased from 70 mmHg to 0 mmHg after the procedure, and clinical symptoms improved dramatically. However, the patient died suddenly 19 months later and autopsy revealed nontransmural myocardial fibrosis with an irregular border in the interventricular septum.