Transmyocardial laser revascularization (TMR) is a new therapeutic principle for patients with coronary artery disease and no possibility of conventional revascularization with CABG or PTCA. The clinical value of the method is not known. Therefore we investigated all 46 patients treated with sole TMR in our center using clinical investigation, LV and coronary angiography, right heart catheterization, MIBI perfusion imaging and myocardial FDG-PET pre- and 6 months post TMR. 117 patients judged not suitable for conventional revascularization procedures were submitted for TMR. The indication for the procedure was reevaluated in every case. 52 patients (mean EF 41 +/- 16%) could be further treated by intensified anti-anginal medication, seven patients received bypass grafts, four patients had PTCA, three patients were listed for heart transplantation, and five patients had a combined CABG plus TMR. Only 46 (38% of the submitted patients, mean EF 55 +/- 15%) were accepted for sole TMR. CCS class of these patients was 3.3 +/- 0.4, mean age was 63.6 +/- 7.3 years, 70% were males. The postoperative mortality within 30 days was 5/46 (10.8%); 9/46 patients (19.5%) suffered from perioperative myocardial infarction. Other complications were ventricular fibrillation in two cases on the second postoperative day and a rupture of the spleen on the 14th postoperative day. 8/46 patients (17%) had wound infections. Survivors showed an improvement in their CCS class (1.9, 2.1, 1.9 after 3, 6 and 12 months, respectively, mean observation time 0.61 +/- 0.4 years). These patients were able to perform bicycle stress tests significantly longer (98 s +/- 9 pre versus 120 +/- 13 s post TMR, p = 0.01). Angiographic EF fell from 57.8% +/- 15% to 52.6% +/- 19% (p = 0.02) and the number of hypokinetic chords rose from 23.6 +/- 20.9% to 30.6 +/- 24.1% per patient (p = 0.008), predominantly in the inferior wall. Nuclear studies showed reduced myocardial perfusion and vitality after TMR. Four patients in the TMR group had reintervention (PTCA) because of progression of coronary sclerosis of native vessels. One patient had mitral valve replacement due to severe regurgitation. Kaplan-Meier analysis showed no significant difference in survival between the TMR and the medical group when stratified according to initial ejection fraction. Sudden death and congestive heart failure are the most important causes of mortality. Our data show that TMR improves symptoms and exercise performance of otherwise not treatable patients with diffuse coronary artery disease. Due to a lack of an improvement of cardiac perfusion, function or prognosis TMR should be used only in highly selected cases when conventional methods fail to improve patients symptoms.