Effects of nicorandil on coronary hemodynamics in ischemic heart disease: comparison with nitroglycerin, nifedipine, and propranolol.

Effects of nicorandil (NC), a newly synthesized nicotinamide derivative (2 mg i.v.), nitroglycerin (TNG, 0.3 mg sublingual), nifedipine (NF, 10 mg sublingual), and propranolol (PR, 0.1 mg/kg i.v.) on coronary hemodynamics were evaluated in 41 patients with ischemic heart disease. Coronary sinus flow (CSF) was measured using a continuous thermodilution method. NC decreased arterial pressure, cardiac output (CO), and pulmonary artery pressure without changing heart rate. Rate-pressure product tended to decrease. Resting CSF was increased by NC (117-148 ml/min, p less than 0.01) and NF. TNG and PR caused no significant changes. Furthermore, NC revealed the highest CSF/CO ratio among four agents and decreased coronary resistance. During rapid atrial pacing, CSF was slightly increased by TNG, but remained unchanged after NC and NF. Myocardial norepinephrine release was markedly increased by TNG (1.5-6.2 ng/min, p less than 0.01) and slightly increased by NF. No changes were noted after NC and PR. Myocardial lactate extraction varied insignificantly in all agents. NC is a potent coronary vasodilator and seems to reduce both preload and afterload; however, in contrast to TNG and NF, NC did not cause reflex tachycardia or an increase of myocardial sympathetic tone.