[Clinical electrophysiological effects of nicorandil on the conduction system in humans]

The electrophysiological effects of nicorandil on the conduction system in humans were examined. Twelve patients with sick sinus syndrome (SSS), 3 patients with AV block and 3 subjects with normal conduction system were studied. The clinical electrophysiological effects were examined before, and 5 min after intravenous administration of nicorandil 2 mg over 3 min. Nicorandil increased heart rate in 6 patients and decreased it in 4. Wenckebach point was increased in 5 patients and decreased in 4. Maximum sinus node recovery time was prolonged in 4 of 12 patients with SSS, and shortened in 3 of them. It was unchanged in 6 patients without SSS. These changes were not statistically significant. There were no changes in PA, AH and HV intervals and refractory periods the atrium, the AV node and ventricle. Nicorandil had no depressant effects on the conduction system of humans. Thus, this drug can be used easily for the treatment of ischemic heart disease in patients with some conduction disturbances.