Effects of coronary artery bypass related conduction defects: a 10-year follow-up study

The aim of this study is to determine the long-term prognostic significance of new permanent conduction defects (CDs) related to coronary artery bypass grafting (CABG), and to assess predisposing factors for increased mortality after CABG.

One hundred and eighty patients who underwent an elective CABG without any evidence of preoperative CDs were followed on average for 9.6 years. Long-term outcome was observed in terms of Kaplan-Meier survival analysis, and several potential pre-, intra- and postoperative factors for increased mortality were analysed using the Cox regression model.

Sixty-three (35.0%) of the patients developed a new CD (CD+ group) before hospital discharge. Early (<30 days) and long-term (>30 days) survival rates were 98.9 and 86.1%, respectively. The long-term survival in CD+ patients was significantly lower that in CD- patients (77.8% vs 90.4%, p = 0.02). However, cardiac survival in CD+ patients and CD- patients did not differ from each other (88.9% and 92.3%, respectively, p=NS). Five independent predictors for increased all cause mortality were identified: diabetes (relative risk ratio 5.99 [2.43-14.78]), number of distal anastomoses (3.20 [1.30-7.88]), a new intraoperative conduction defect (2.83 [95% CI 1.24-6.49]), preoperative ejection fraction <50% (2.60 [1.08-6.27]) and perfusion time (1.02 [1.01-1.03]).

Excellent survival rates can be obtained 10 years after CABG. CDs were not related to increased cardiac mortality. The appearance of preoperative diabetes, intraoperative perfusion time, number of distal anastomoses performed, CABG derived permanent CDs and low preoperative ejection fraction are associated with higher all cause mortality during the long-term follow-up.