Natural History and Predictors of Temporary Epicardial Pacemaker Wire Function in Patients after Open Heart Surgery

Study Objectives: To assess the short-term reliability of temporary epicardial pacing wires in patients after open heart surgery and to determine the influence of preoperative factors on the performance of these wires. Patients and Methods: In this prospective, longitudinal cohort study, 60 patients (41 men) with a mean age of 66.8 ± 8.9 years were studied for 5.3 ± 1.1 days postoperatively. Each patient’s history, physical findings, hemodynamics and echocardiographic data were analyzed. Postoperatively, capture threshold, the electrogram amplitude and slew rate, and the lead impedance were determined daily in both chambers. Results: Both atrial and ventricular thresholds increased significantly (p < 0.001) by the 4th postoperative day. The P-wave amplitudes were consistently less than half of the R-wave amplitudes. Both P- and R-wave amplitudes deteriorated significantly by the 2nd postoperative day (p < 0.001 and p < 0.02, respectively). Atrial and ventricular slew rates and lead impedance decreased significantly during the observation period (p < 0.002). Conclusion: Although both atrial and ventricular temporary epicardial leads are reliable for short-term use, their function deteriorates on a daily basis. Perioperative factors are generally not helpful in predicting the performance of temporary epicardial pacing wires.