Thermographic evaluation of myocardial temperature during infusion of cold cardioplegia.

Delay in myocardial cooling during an infusion of cold cardioplegic solution may occur in patients with coronary artery disease. Forty patients with significant stenosis of the left anterior descending coronary artery (LAD) were divided into 3 groups according to the extent of the LAD stenosis. Group A consisted of 12 patients with 70% stenosis. Group B included 23 patients with 90% stenosis, and in group C there were 5 patients with LAD occlusion. Myocardial temperature was measured with a thermocamera during infusion of 2000 ml 8 to 10 degrees C cold Bretschneider's cardioplegic solution and compared to 10 other patients without coronary artery disease undergoing mitral valve replacement (group D). In group A the myocardium cooled to 15 degrees C after 4 1/2 minutes and to 12 degrees C after 10 minutes. In group B the myocardial temperature was 15 degrees C after 5 minutes and 12 degrees C after 10 minutes. In group C the temperature reached 18 degrees C after 5 minutes and 14 degrees C after 10 minutes. In group D the myocardial temperature was 12 degrees C after 3 minutes and 10 degrees C after 7 minutes. This study shows far better myocardial cooling rates in patients with unobstructed coronary arteries.