BACKGROUND: Percutaneous myocardial revascularization with laser (PMR) is a catheter-based technique that has generated much interest in the treatment of patients with severe coronary artery disease. Several mechanisms have been proposed to explain the reported clinical benefits of this technique. Cardiac autonomic denervation is among these. METHODS: We studied 32 consecutive patients with chronic severe angina not suitable for other revascularization approaches. Canadian Class Society (CCS) class clinical assessment, Naughton exercise stress test, and scintigraphic myocardial perfusion were evaluated before and 1 and 6 months after PMR. Ewing\'s autonomic tests, heart rate variability (HRV), and plasmatic catecholamines were assessed before revascularization in non-diabetic and diabetic patients and repeated 1 month after PMR in 13 non-diabetics. A psychological test was carried out before PMR to evaluate the attitude towards this new procedure. RESULTS: All the markers of autonomic cardiac control were unmodified after the procedure. Moreover, scintigraphic perfusion measured in the lasered areas was similar before and after the procedure. On the other hand, the clinical conditions significantly improved (CCS class from 3+/-0.8 to 1.9+/-0.9 at 1 month, P<0.01) and the exercise-related ischemic threshold was significantly better (from 311+/-28 to 453+/-51 s, P<0.05). The patients with a psychologically \'positive\' expectation for this new procedure had results comparable to those with a \'negative\' expectation. CONCLUSIONS: PMR improves symptoms in patients with end-stage coronary artery disease in the absence of any detectable clinical sign of heart denervation.