The Protective Effect of Adenosine Included Cardioplegia in Myocardial Ischemia

Yoo, Kyung Jong; Kang, Meyun Shick; Lee, Kyo Jun; Lim, Sang Hyeun; Kim, Jong Hoon; Cho, Bum Koo

Abstract

Although the effects of adenosine on the heart, including the clinical suppression of cardiac arrhythmias, have been recognized for more than half a century, it is only in the last decade that the therapeutic potential of adenosine has been recognized. The objective of this study was to determine if augmentation of myocardial adenosine levels during global ischemia improves functional recovery after reperfusion. We used to modified Langendorff system to evaluate myocardial protective effect. Isolated rat hearts were subjected to 90 minutes of deep hypothermic arrest(15degrees C) with modified St. Thomas' Hospital cardioplegic solution used to provide myocardial protection. Myocardial adenosine levels were augmented during ischemia by providing exogenous adenosine in the cardioplegic solution. Two groups of hearts were studied: (1) control group(n=10) - cardioplegia alone; (2) adenosine group(n=10) - adenosine(0.75mg/Kg/min) added to the cardioplegic solution. Significantly better percent recovery(p<0.01) in hemodynamics(except heart rate) at 60 minutes after reperfusion was evident compared to baseline values in the adenosine group. (systolic aortic pressure : 78.5+/-3.6% vs 66.6+/-5.9%, aortic overflow volume : 61.7+/- 11.6% vs 37.2+/-15.4%, coronary flow volume : 77.1+/-7.5% vs 57.2+/-11.1%, and cardiac output : 65.6+/-11.5% vs 44.2+/-12.4%). Heart rate was similar in two groups(94.4+/-4.8% vs 95.3 +/- 6.8%). Adenosine groups resulted in significantly rapid recovery time of heart beat after reperfusion(p<0.01) (24.5+/-7.6 sec. vs 179.0+/-131.1sec.). In biochemical study, CPK levels(0.1+/-0.3U/L vs 1.4+/-0.8U/L) and lactic acid levels(0.08+/-0.1mmol/L vs 0.34+/-0.2 mmol/L) were significantly low in adenosine groups(p<0.01). We concluded that adenosine included cardioplegia have better recovery effects after reperfusion in myocardial ischemia compared to adenosine free cardioplegia.