The risks and long-term outcome after 845 elective percutaneous transluminal coronary angioplasties (PTCA) in patients with left ventricular (LV) dysfunction (ejection fraction less than or equal to 40%) were examined. Procedural results were compared with 8,117 consecutive procedures in patients with ejection fractions greater than 40%. The patients with LV dysfunction were older (63 vs 60 years, p less than 0.01), had a greater incidence of prior myocardial infarction (84 vs 45%, p less than 0.001), prior bypass surgery (39 vs 21%, p less than 0.001), 3-vessel disease (62 vs 33%, p less than 0.001), and class IV angina (48 vs 41%, p less than 0.01) than the control group. Angiographic success was lower (93 vs 95%, p less than 0.01), and overall procedural mortality was increased ( 4 vs 1%, p less than 0.001) in the study group. Emergency surgery rates were identical (2%). No significant difference was found in rates of nonfatal Q-wave myocardial infarction (2 vs 1%). At mean follow-up of 33.5 months, 15% of the patients with LV dysfunction required late bypass surgery, 27% underwent repeat PTCA, and 59% were angina free. Actuarial survival at 1 and 4 years was 87 and 69%, respectively. Cox regression analysis identified 3-vessel disease, age greater than or equal to 70 years, class IV angina and incomplete revascularization as correlates of long-term mortality. These data suggest that PTCA may be an effective treatment for coronary artery disease in patients with LV dysfunction.