Effect of Global Ischemic Preconditioning After Cardioplegic Arrest: Langendorff Isolated Heart Study

Chun, Young Jin; Lee, In Sung; Kim, Yeon Soo; Choi, Young Ho; Kim, Kwang Taik; Kim, Hyoung Mook; Kim, Hak Jae; Lee, Kun

Abstract

Ischemic preconditioning is known to have protective effect on myocardial function at prolonged ischemic insult but the mechanism of the effect is not clearly known. The effect of the preconditioning on the global ischemia using cardioplegic solution is not well known. To evaluate the effect of global myocardial preconditioning on the functional recovery after cardioplegic arrest and two hours of hypothermic storage, we used the isolated rat heart and two hours cardioplegic arrest time at 0degree C. In the experimental group (n=10), after baseline functional data was obtained, ischemic preconditioning was induced with 1 min of global normothermic ischemia for three times before the arrest period. In the control group (n=10), hearts underwent no ischemic precondi- tioning. After 2 hrs of cardioplegic arrest and storage in the 0degree C cardioplegic solution reperfusion was done and hemodynamic data were collected at post-reperfusion 20 min. Heart with ischemic preconditioning showed improved functional recovery at post reperfusion 20 min in peak developed pressure and dP/dT. In percent change of the peak pressure, preconditioning group showed 93.20+/-15.7% recovery rate compared to baseline data, and control group showed 67.3+/-15.6% recovery rate. In percent change of the dP/dT, control group showed 54.7+/-18.2% recovery rate and preconditioning group showed 78.1+/-15.1% recovery rate. Percent changes in heart rate and coronary flow showed no significant difference between two groups and there was no significant differences in amount of cardioplegic delivery between groups. Our data suggest ischemic preconditioning may have protective effect on recovery state after cardioplegic arrest and 2 hr ischemic storage of isolated rat heart and its mechanism is not related to the amount of the cardioplegic delivery amount.