Background: Epicardial pacemakers are known as an alternative for endocardial pacemakers in some cases such as heart block, and complex congenital heart diseases. Considering recent advances and improvement of epicardial lead subtypes, it is essential to investigate the long-term function of them. In this study, we aimed to assess the sensing and pacing characteristics, and survival of bipolar steroid-eluting and unipolar non-steroid-eluting epicardial pacemakers. Methods: We conducted an entirely concentrated search on the documents of all patients who had undergone epicardial lead implantation in the Shaheed Rajaie Cardiovascular, Medical & Research Center during 2015-2018. Implant, and follow up data were extracted. Kaplan Meier analysis and Weibull regression hazards model were applied for the survival analysis. Results: eighty-nine leads were implanted for 77 patients. Of the total leads, 52.81%, 53.93%, and 47.19% were implanted in children (under-18-year-old), females, and patients with congenital heart diseases, respectively. Bipolar steroid-eluting leads comprised 33.71% of 89 leads. Pacing threshold of unipolar non-steroid-eluting leads that were implanted on the left ventricle and right atrium increased significantly during the follow up to greater records than bipolar steroid-eluting leads. Survival analysis also revealed that bipolar steroid-eluting leads are significantly better in 48-month survival (Weibull HR: 0.13 (95%CI, 0.02-0.99), p-value, 0.049). Age, ventricular location of the lead, and acute pacing characteristics were not associated with survival. Conclusions: Bipolar steroid-eluting epicardial leads have an acceptable survival compared with unipolar non-steroid-eluting, without a significant difference regarding patients age. Therefore, they could be an excellent alternative for endocardial ones.

34 years old man with frequent palpitations referred to our center. Three standard diagnostic catheters were introduced through left and right femoral veins and placed in right atrium, right ventricle and coronary sinus positions. A narrow complex tachycardia with long RP-short PR could be initiated after extarstimulation from HRA following an AV nodal jump. The earliest retrograde atrial activation was recorded from His bundle position. RV apical pacing showed decremental with earliest atrial activation in His area, although no fused V-A potential was recorded in either CS or His position. His synchronous pacing from RV apex failed to advance or reset the arrhythmia. Morady maneuver by RV overdrive pacing repeatedly terminated the tachycardia. Mapping was initiated from His region and extended to all anticipated areas from parahisian region to tricuspid annulus, posteroseptal TV ring and CS. The construction of RA activation map failed to reveal earliest activation site. Mapping catheter was introduced through femoral artery and advanced to the left ventricle. At anteroseptal mitral annulus corresponding to Aorto-Mitral continuity, we recorded the earliest retrograde atrial activation (A-distal CS =50 ms). RF energy (30 W) was delivered using an irrigate tip catheter during tachycardia and resulted in termination of tachycardia immediately.