Comparison of the Results of Left Ventricular Epicardial and Endocardial Pacing Through the Coronary Sinus in Patients With Triple-Chamber Pacing

Considering the many reports of elevated threshold levels and left ventricular dysfunction in epicardial leads, the evaluation of the short- and long-term efficacy of this type of leads is necessary in comparison with the coronary sinus (CS) leads. The present study compared left ventricular epicardial pacing via surgery and CS pacing in patients with triple- chamber pacemakers. This retrospective cohort study was performed on patients referred for cardiac resynchronization therapy. The patients were re-evaluated with ECG after pacemaker implantation and before discharge. The evaluations were performed in 2 patient groups under left ventricular epicardial pacing and CS pacing. At 12 months’ follow-up, the mean left ventricular pacing lead threshold was significantly higher in the patients with epicardial lead pacing than in those with endocardial lead pacing. Additionally, regarding the ECG pattern after lead pacing, the morphology of QRS at V1 lead and also the type of the QRS axis significantly differed between epicardial pacing and CS pacing 6–12 months after pacemaker implantation. The mean left ventricular pacing lead threshold was at its highest in the posterolateral area and at its lowest in the anterolateral area, but without any significant difference. Comparisons between the results and the long-term effects of CS pacing and surgical epicardial lead pacing in the present study indicated that the increase and changes in the left ventricular leading threshold in the epicardial pacing lead were much more pronounced than those in CS pacing through the CS. Therefore, the use of CS leads might be preferred to pericardial leads due to the stability of left ventricular leads.