Feasibility of temporary biventricular pacing in patients with reduced left ventricular function after coronary artery bypass grafting

Background and Methods: Biventricular pacing improves hemodynamics after weaning from cardiopulmonary bypass inpatients with severely reduced left ventricular (LV) function undergoing coronary artery bypass grafting (CABG). We examined the feasibility of temporary biventricular pacing for 96 hours postoperatively. Unipolar epicardial wires were placed on the roof of the right atrium (RA), the right ventricular (RV) outflow tract, and the LV free lateral wall and connected to an external pacing device in 51 patients (mean LV ejection fraction 35 +/- 4%). Pacing and sensing thresholds, lead survival and incidence of pacemaker dysfunction were determined. Results: Atrial and RV pacing thresholds increased significantly by the 4th postoperative day, from 1.6 +/- 0.2 to 2.5 +/- 0.3 V at 0.5 ms (P=0.03) at the RA,1.4 +/- 0.3 V to 2.7 +/- 0.4 mV (P=0.01) at the RV, and 1.9 +/- 0.6 V to 2.9 +/- 0.7 mV (P = 0.3) at the LV, while sensing thresholds decreased from 2.0 +/- 0.2 to 1.7 +/- 0.2 mV(P=0.18) at the RA,7.2 +/- 0.8 to 5.1 +/- 0.7 mV (P=0.05) at the RV, and 9.4 +/- 1.3 to 5.5 +/- 1.1 mV (P = 0.02) at the LV. The cumulative overall incidence of lead failure was 24% by the 4th postoperative day, and was similar at the RV and LV. We observed no ventricular proarrhythmia due to pacing or temporary pacemaker malfunction. Conclusions: Biventricular pacing after CABG using a standard external pacing system was feasible and safe.