Beneficial Effects of Intracoronary Nicardipine on Hypoxic Myocardium

Abstract

Regional effects of intracoronary administration of nicardipine, a dihydropyridine derivative with calcium blocking activity, were studied in 13 open-chest dogs. Hypoxic, constant-flow perfusion was done in the area supplied by the distal left anterior descending artery. The 5-min regional hypoxic perfusion did not result in significant alterations in either heart rate or aortic pressure in 6 control dogs perfused with original Krebs-Henseleit solution (KHS), which was deoxygenized by mixed gas (95%N₂ and 5%CO₂), and in 7 dogs perfused with nicardipine-containing (0.2mg/ dl) KHS. A transmural biopsy after 5min of perfusion revealed a less severe metabolic deterioration in nicardipine-treated dogs than in control dogs, as indicated by a higher ATP content (2.84±0.43 vs. 2.23±0.45μmol/g, wet weight). The sequence of regional contractile deterioration was not different between the 2 groups. In conclusion, regional nicardipine administration showed a myocardial protective effect which was not mediated by afterload reduction in the whole heart.