Ischemic myocardial damage is inevitable to cardiac surgery. Myocardial damage after initiation of reperfusion through the coronary arteries is one of the most important determinants of a successful surgery. Adenosine is a potent vasodilator, and
is
also known to induce rapid cardioplegic arrest by its property of antagonizing cardiac calcium channels and activating the potassium channel. Thus, we initiated this study with adenosine to improve postischemic recovery in the isolated rat heart.
We
tested the hypothesis that adenosine could be more effective than potassium in inducing rapid cardiac arrest and enhancing postischemic hemodynamic recovery. Isolated rat hearts, connected to the Langendorff appratus, were perfused with
Krebs-Henseleit
buffer and all hearts were subjected to arrest for 60minutes. Three groups of hearts were studied according to the composition of cardioplegic solutions: Group A(n=10), adenosine 10mmol/L+potassium free modified St. Thomas cardioplegia : Group
B(n=10),
adenosine 400mol/L+St. Thomas cardioplegia: Group C(control,n=10), St. Thomas cardioplegia. Adenosine-treated groups(group A & B) resulted in more rapid cardiac arrest than control group(C)(p<0.01). There was greater improvement in recovery of
coronary
blood flood flow at 20 and 30 minutes of reperfusion in group A and at 20 minutes in group B when compared with control group(p<0.01). Recovery of systolic blood pressure at 10 minutes after reperfusion in group A and B was significantly superior
to
that in group C (p<0.01). Recovery of dp/dt at 10 minute after reperfusion in group A was also significantly superior superior to group C(p<0.05). Group A and B showed better recovery rates than control group in aortic blood flow, cardiac output,
and
heart rate, but there were no statistical differences. CPK levels of coronary flow in group A were significahtly low(p<0.01). We concluded that adenosine-entiched cardioplegic solutions have better effects on rapid cardiac arrest and postischemic
recovery when compared with potassium cardioplegia.
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