Nicorandil has pharmacologic effects similar to nitroglycerin and potassium in respect to the channel opening action in vascular smooth muscle cells. We examined hemodynamic changes in patients following nicorandil infusion. We investigated the action mechanism of nicorandil, and whether nicorandil affects hemodynamic changes in patients receiving antianginal medication.

A total of 17 patients (11 normal control group, 6 coronary artery disease group) undergoing cardiac catheterization for investigation of chest pain participated in this study. During cardiac catheterization, nicorandil was infused into the pulmonary artery at a dose of 80 microgram/kg over a period of 1 min. Hemodynamic parameters were measured before and at 5, 10 and 20 minutes after nicorandil infusion.

Five minutes after nicorandil infusion, the maximal changes in preload and afterload hemodynamic parameters were observed in both the coronary artery disease and control group. Changes of preload parameters were sustained longer than those of afterload parameters, and were maintained until 20 minutes after the infusion. Afterload parameters (heart rate and cardiac output), were slowly normalized five minutes after the infusion. In the coronary artery disease group with antianginal medication, additive hemodynamic changes were also seen after the infusion, although the degree of changes were small.

Following nicorandil infusion, both the preload and afterload hemodynamic parameters decreased, and the preload parameters showed a larger decrease for a longer period than the afterload parameters. In the coronary artery disease group with antianginal medication, additive hemodynamic changes were also seen following nicorandil infusion.