A 29-year-old man with non-familiar hypertrophic cardiomyopathy died suddenly. The patient experienced recurrent episodes of palpitation both at rest and during exercise. M-mode and 2-D echocardiograms showed severe asymmetric septal hypertrophy (IVS/LVPW ratio 3:1) and systolic anterior motion of anterior leaflet of the mitral valve. The ECG demonstrated deep "Q" waves from the inferior leads and inverted "T" waves in V1 to V6, but failed to register arrhythmias. Holter monitoring had been planned in order to achieve information for pharmacologic therapy, but unfortunately the patient died during the stand-by. Postmortem examination showed severe asymmetric septal hypertrophy with fibrosis and wide-spread "myocardial disarray".