Prognosis in hypertrophic obstructive cardiomyopathy.

Thirty-eight non-operated patients with hypertrophic obstructive cardiomyopathy (HOCM) were followed for 1--18 years (mean 8). Twelve patients died, nine of them instantaneously without any other apparent cause of death. The symptoms on the first admission did not discriminate between those who died and those who survived during the observation period, nor did the findings at heart catheterization at rest or left ventricular angiocardiography. However, cardiac enlargement on the first chest X-ray was significantly more common in the decreased group, 75% against 27%, as was the complete absence of a q-wave in lead III on the first ECG, 83% against 42%. The combination of complete lack of q in lead III and cardiac enlargement on chest X-ray at the initial examination was present in 9 of the 12 deceased (75%) and in only 3 of 24 survivors (13%). This can be used to select patients for long-term prophylaxis against ventricular fibrillation which, according to the literature, is the main mechanism of instantaneous death in HOCM.