Pressure-Controlled Reperfusion Improves Postischemic Recovery of LV-Hypertrophied Rat Hearts

Abstract

The influence of pressure-con trolled postischemic reperfusion (Rp) on functional and metabolic parame ters in hearts of sham-operated rats and hypertrophied hearts of rats with aortic constriction were studied. Hy pertrophied hearts are considered to be more susceptible to ischemia.

The hearts were perfused in the Langendorff-technique for thirty minutes at 35°C with Krebs-Hense leit bicarbonate buffer at a perfusion pressure (PP) of 75 mmHg and for five minutes at 15°C with St. Thomas' Hospital cardioplegic solu tion at a PP of 60 mmHg. After a per iod of global ischemia of forty min utes' duration at 15 ° C, reperfusion was started either abruptly (aRp: PP 75 mmHg immediately) or gently (gRp: PP 75 mmHg within thirty minutes); it lasted for forty-five min utes. Intraventricular peak systolic pressure (ISP) was monitored and en ergy-rich compounds (ATP, ADP, AMP, CrP, free Cr) were analyzed.

In normal hearts, metabolic re covery was not affected by the mode of reperfusion, but functional recov ery (ISP) averaged 88% of the preis chemic control value after gRp as compared with 73% after aRp.

In hypertrophied hearts, gentle reperfusion ameliorated both meta bolic and functional recovery. At forty-five minute recovery, CrP aver aged 5.1 μmol/g ww after aRp and 6.6 μmol/g ww after gRp (p < 0.01), and ISP amounted to 73% of the pre ischemic control after aRp and to 85% after gRp.