Methods: Eighteen consecutive patients (13 males, 5 females; mean age 66.2±12.4; range 47 to 77 years) undergoing coronary artery bypass grafting who were candidates for a pacemaker placement postoperatively were included in the study. Temporary epicardial pacing wires were intraoperatively placed both on the right ventricle (RV) and on the left ventricle (LV) in all patients. The epicardial wires were placed on the RV to the outflow tract and on the LV to the apex. On the fifth postoperative day echocardiography (Vivid 5, Vingmed, General Electric Healthcare) was performed and tissue Doppler measurements were taken during basal, RV pacing and LV pacing. During RV and LV pacing, the heart rate was increased above the basal rate. During the analysis, at least three cardiac cycles were recorded in the tissue velocity imaging mode. The recorded images were analyzed by EchoPAC (EchoPAC 6.3, Vingmed-General Electric Healthcare). In the images that were collected for tissue synchronization LV septal and lateral segments were marked and were subsequently analyzed for delay in the septo-lateral segment. The results were shown in mean ± standard deviation and statistical analysis was performed using the Wilcoxon signed rank test (p<0.05).

Results: In all patients, during RV pacing significant intraventricular delay was documented between the septum and the lateral wall (52.9±20.7 ms versus 20.6±14.6 ms, p<0.001). During LV pacing in all patients intraventricular delay was measured shorter than the basal value (12.7±12.1 ms versus 20.6±14.6 ms, p=0.001). No complications were observed in all patients during the placement of intraoperative pacemaker wire, in the postoperative period when asynchrony measurements were performed and after the removal of the wires.

Conclusion: In patients undergoing coronary artery bypass grafting surgery the temporary epicardial pacing wires should be placed on the left ventricle instead of the right ventricle.