Electrical neuromodulation improves myocardial perfusion and ameliorates refractory angina pectoris in patients with syndrome X: fad or future?

At present, there is no reliable antianginal drug therapy for patients with cardiac syndrome X. Therefore, the effect of electrical neuromodulation on refractory angina pectoris and myocardial perfusion in cardiac syndrome X was assessed. Eight patients (aged 55+/-7 years) with heterogeneous myocardial perfusion and no esophageal abnormalities were included. The subjects were nonresponders to antianginal drug therapy. Angina pectoris attacks and myocardial perfusion dynamics were evaluated by positron emission tomography at baseline and following 4 weeks of (transcutaneous electrical nerve stimulation) TENS. Following TENS there was a reduction of angina pectoris episodes (baseline 20+/-3, TENS 3+/-1; p=0.012), and short acting nitroglycerin intake per week (baseline 10+/-3, TENS 2+/-1; p=0.008). The rate pressure product (mmHg min(-1)) during the cold pressor test (CPT) was reduced during TENS (baseline 12800+/-1200, TENS 11500+/-900; p=0.02). Following TENS, the perfusion reserve ratio between rest and dipyridamole flow increased (baseline 1.59+/-0.15, TENS 1.90+/-0.11 ml min(-1)x 100g; p=0.05). The coronary vascular resistance had a trend towards a reduction (baseline 0.96+/-0.04, TENS 0.85+/-0.06 mmHg min(-1)x 100 g/ml; p=0.06) during CPT. This observation may suggest that neurostimulation improves angina pectoris with a concomitant improvement of myocardial perfusion in cardiac syndrome X.