Therapy for ischaemic congestive heart failure has been well documented in patients with angina. The goal of this study was to compare the benefit of revascularization in patients with and without chest pain. A series of 180 patients with ischaemic heart failure symptoms (New York Heart Association III-IV class) and low ejection fraction (28+/-9%) were recruited and followed for 3 years. Group A, 97/180 patients, had chest pain. Group B, 83/180 patients, did not have angina. The two groups did not differ with respect to known determinants of postinfarction prognosis. The relative presence of viable tissue versus scar was defined by Thallium-201 uptake. Intraoperative mortality was 5 and 7% in Groups A and B (P=not significant); in particular, in both groups, it was lower when only patients with mostly viable myocardium were considered. At 6 months, the presence of viable myocardium was highly predictive of improvement of heart failure symptoms and wall motion abnormalities. At 3 years, revascularized patients of Group A with mostly viable myocardium had a survival of 89% compared to 87% for corresponding Group B patients (P=not significant). In conclusion, similarly to patients with angina, patients with left ventricular dysfunction, maintained viability and without anginal symptoms may benefit from coronary revascularization.