Pretreatment with nicardipine preserves ventricular function after hypothermic ischemic arrest

Abstract Calcium antagonists have a protective effect on postischemic myocardial function when included in normothermic cardiopiegia solutions. This effect varies with the calcium antagonist, but is generally lost under hypothermic conditions. The hypothesis tested was that a calcium antagonist would increase postischemic myocardial performance if given before the onset of hypothermic arrest. Isolated working rat hearts were used with an oxygenated modified Krebs-Henseleit buffer solution as a perfusion media. Rats were pretreated with 1 of 9 doses of a nicardipine solution (0 to 100 μg/kg, intraperitoneally) 20 minutes before excision of the heart. Nicardipine is a light-stable, water-soluble calcium antagonist with minimal myocardial depressant effects. The hearts were arrested for 25 minutes at 37 °C or 93 minutes at 24 °C with 20 mL of cardiopiegia solution containing 0.05 mmol/L CaCl 2 . Postischemic performance and adenosine triphosphate content were used as determinants of efficacy. Eighty-three percent of 101 treated hearts recovered in contrast to a mortality of 50% in the 24 nontreated hearts. Pretreatment with 25 μg/kg significantly increased ( p