We prospectively studied 74 men 39-78 years of age, with significant (> or = 70%) stenosis of one or more coronary arteries. The investigation included coronary arteriography, ventriculography and ambulatory monitoring of cardio-respiratory variables during sleep using the MESAM-IV. We found 48 subjects with a respiratory disturbance index (RDI) > or = 10 events per hour. Our analyses failed to establish a relationship between RDI, myocardial infarction and known risk factors for coronary heart disease. Similarly, there was no relationship between RDI, number of coronary vessels involved, or left ventricular ejection fraction. Compared to general population studies, however, our group of coronary heart disease patients had a high incidence of obstructive sleep apnea syndrome (35%).