BACKGROUND Transmyocardial revascularization using a high-energy CO2 laser has emerged as a new therapeutic option for patients with severe diffuse coronary artery disease refractory to conventional modes of therapy. METHODS From December 1994 to September 1997, 102 patients underwent isolated transmyocardial revascularization. The mean age was 56.7 +/- 9.2 years and 92.15% were men. Mean preoperative angina class and ejection fraction were 2.6 +/- 0.7 and 44.7% +/- 10.5%, respectively. Diabetes was present in 49.01% of patients, 32.3% had history of previous myocardial infarction, and 12.7% had undergone a previous coronary artery bypass graft procedure. An average number of 23 +/- 8 channels were created in each patient using an 800-W CO2 laser. RESULTS The early mortality was 14.7% and univariate predictors of mortality were age more than 55 years, female sex, creatine kinase more than 1,600 IU, absence of intercoronary collaterals, and mean pulmonary artery pressure greater than 21 mm Hg. At 1-year follow-up there was significant improvement in angina class and effort tolerance but no significant change in left ventricular ejection fraction. CONCLUSIONS We conclude that transmyocardial revascularization provides symptomatic benefit and improves exercise tolerance in a group of patients suffering from disabling angina not amenable to other modes of treatment. The high early mortality can be brought down with strict patient selection criteria. The mechanism of beneficial effects is uncertain and patency of laser channels is controversial, but laser-induced neoangiogenesis is being looked on as a possible explanation.