Mechanical Restitution and Inotropic Reserve of the Rat Heart Following Heterothermal Global Ischemia

Abstract

The efficacy of low temperature on the post-ischemic recovery of the heart activity was studied using the technique of heterothermal irrigation of the ventricles. During one hour lasting no-flow ischemia, the cavity of one ventricle was irrigated with 37°C non-oxygenated Krebs-Henseleit (KH) buffer, the other with 20°C KH. During the reperfusion period, the intraventricular pressures were simultaneously recorded by inserted balloons and compared with the post-ischemic data. Ventricular end diastolic pressure was kept constant for all protocols of study. Control and reperfusion temperature was 34°C. In protocol ‘A’, right ventricle (RV) irrigation temperature was kept at 37°C and the left ventricle (LV) at 20°C. In protocol ‘B’, the temperature gradient was reversed. This technique produced a temperature gradient of 7–10°C between RV and LV.