Intramyocardial Temperature Following Various Cooling Procedures

Abstract

In 12 dogs on cardiopulmonary bypass, the intramyocardial temperatures in the anterior and the posterior wall of the left ventricle and in the septum were measured with microthermoelectrodes when different cooling procedures were used during 60 min of anoxic cardiac arrest. External cooling with 4°C glucose (5.5%) solution dripping into the pericardial sac did not lower the temperature in the septum or in the posterior wall. Packing the heart in slushed ice after injection of the same glucose solution into the coronary tree reduced the septum and posterior wall temperature to around 30°C. This cooling procedure, in combination with general moderate hypothermia, lowered the temperature to about 20°C in these parts of the heart. Only when combined with general hypothermia did local cooling achieve low temperatures in all regions of the myocardium.