Low myocardial temperatures are associated with postoperative conduction defects after coronary artery bypass surgery.

The incidence and significance of postoperative conduction defects after coronary artery bypass surgery were investigated prospectively in 181 patients. Several pre- and perioperative variables, especially the temperature in three regions of the myocardium, were recorded as explanatory variables. The incidence of conduction defect(s) in the immediate postoperative electrocardiogram (ECG) was 55.8%, and 35.9% of the patients had a conduction defect when leaving hospital. Two patients had a permanent third degree atrioventricular (AV) block. Five pacemakers were implanted. Left main coronary artery stenosis was more common (P < 0.01), and the perioperative myocardial temperatures (P < 0.05-0.01) were lower in patients with conduction defects. These patients had also low postoperative cardiac output more often (P < 0.001), their creatine kinase myocardial (MB) fraction values were higher (P < 0.01), and they stayed in hospital longer (P < 0.05). Right bundle branch block had no significant association with the studied variables.