Protective effect of lidocaine on the ischemic-reperfused rat heart: a phosphorus 31 nuclear magnetic resonance study.

Using an isolated perfused heart preparation of the rat, the effects of lidocaine (Na+ channel blocker) on ischemic derangements of the mechanical function and energy metabolism of the ventricular myocardium were studied. The myocardial tissue levels of creatine phosphate (CP), ATP, inorganic phosphate (PI) and pH were determined using 31P-NMR. Global ischemia was induced by cross-clamping the aortic inflow line for 20 min, which resulted in a fall in CP, ATP, and pH, and a rise in Pi. The test hearts were perfused with a lidocaine-containing solution (10(-7) M) for 20 min prior to the induction of global ischemia and for 80 min after reperfusion. No significant decline of the myocardial mechanical function expressed as "left ventricular pressure x heart rate" was observed in lidocaine-treated hearts. Lidocaine significantly suppressed the fall in the myocardial ATP and pH during ischemia. Furthermore, in the reperfusion phase, restoration of high ATP levels was observed with the lidocaine-treated heart. These results manifest the beneficial effect of lidocaine on ischemia-induced cell injury.