The bail out option; using endocardial pacing and defibrillation leads epicardially
Authors: Hammouda T , Hosny H , Nasr A , Ahmed E , Abdelfattah M , Khalil A M , Elhusseny M W , Kamel O 
Published: May 2024

Abstract

Introduction
Although transvenous implantation of cardiac pacemakers and defibrillators is technically feasible and less invasive than surgical placement of epicardial leads, certain patients including pediatric patients and patients with complex congenital heart disease will require epicardial pacing and most of them will need pacing throughout their whole life.
There are specific leads for epicardial pacing which were developed over time to the currently used bipolar steroid-eluting epicardial leads which may be rarely nationally unavailable. In addition, there are no available dedicated epicardial shock leads (1,2).
There is no enough data on the techniques, feasibility, and efficacy of using endocardial leads, including shock leads for epicardial pacing/ defibrillation (3).

Purpose
We aim to describe our center’s experience in implanting endocardial leads for epicardial pacing or defibrillation and to assess its feasibility & durability.

Methods
Due to periods of national unavailability of epicardial permanent pacing leads and worldwide unavailability of dedicated epicardial shock leads, a limited cohort of patients requiring urgent epicardial pacing/ ICDs were offered pacing through epicardially implanted endocardial leads. The lead screw is advanced into myocardium, then a purse-string suture is placed around and tied to the lead for fixation. Ventricular pacing lead is fixed to LV apex, while atrial lead is fixed to RA free wall. Shock coils are fixed to LV and RA free walls (Fig. 1). We retrospectively revised our records for these patients & analyzed their clinical data, follow up programming parameters including sensing, pacing thresholds and impedances.

Results
In the last 8 years, surgeons implanted 9 endocardial leads epicardially. Two were pacing leads implanted for ventricular and atrial pacing in two different pediatric patients, and 7 were shock leads in patients with life threatening VTs despite medical treatment. The patients with ICDs were as follows: one was an adult patient with a Glenn shunt. The other 6 patients were pediatrics with low body weight; 4 of them had long QT syndrome and two had idiopathic VF. The mean follow-up periods were 38 months. Throughout the visits, the pacing thresholds, sensing functions, lead and shock impedances were stable in all patients (Table 1). Two of the patients with epicardial ICDs received appropriate shocks. None received inappropriate shocks. So far, only one patient required battery replacement.

Conclusion
In view of our findings, using endocardial leads as a bail out alternative to epicardial leads for pacing or defibrillation appears to be safe and effective. This finding is essentially important regarding the shock leads as there are no dedicated epicardial defibrillation leads. It should be noted that these results depend largely on the surgeon’s experience and on achieving acceptable pacing parameters and defibrillation thresholds intraoperatively.Table 1Figure 1