[The effects of calcium concentration of reperfusion solution upon myocardial protection]

The effects of several calcium concentrations in reperfusion solution were studied. Experimental time course was as followed: 20 min working perfusion, 3 min cardioplegic infusion with St. Thomas cardioplegic solution (STS) followed by global ischemia for 30 min at 37.5 degrees C, 15 min early Langendorff reperfusion with reperfusion solution and 5 min late reperfusion with Krebs Henseleit bicarbonate buffer [( Calcium] = 2.5 mM), followed by 20 min working perfusion. Percent recoveries of aortic flow at the Ca concentration of 0, 0.1, 0.6, 1.2, 1.8, 2.5 mM were 0, 14 +/- 1, 43 +/- 4, 64 +/- 3, 55 +/- 2, 59 +/- 1 (%), respectively. Our data indicated that reperfusion solution with less than 1.2 mM calcium reduced the protective properties of STS.