LONG TERM SAFETY OF ABANDONED CARDIAC IMPLANTABLE ELECTRONIC DEVICES

BACKGROUND Cardiac implantable electronic devices (CIEDs) usually require the use of transvenous leads. A long-term complication of this can be venous system occlusion. This can preclude insertion of new transvenous leads, which is usually required to upgrade a device or supplant a defective lead; these patients require a new CIED system to be implanted on the contralateral side. Removal of the pre-existing device and/or leads carries substantial risks, including procedural complications and infection. An alternative is to leave the old device in-situ ("abandoned") with appropriate programming to minimize interaction. However, there is limited long term information about the safety and potential interaction between devices. METHODS AND RESULTS We identified 12045 patients who underwent CIED implant and had a CXR post-procedure at the Ottawa Heart Institute between December 1998 and September 2020. We used an artificial intelligence-based algorithm to identify all patients who had radiographic evidence of more than one CIED system. Our study cohort consisted of 17 patients. The average age was 66.7 ± 14.6 years; 3 (18%) were female. The average PADIT score was 8.2 ± 1.6, corresponding to a >3% annual risk of hospitalization for CIED infection with intervention on the pre-existing device pocket. The average time between the abandoned and new device implant was 4.9 ± 3.3 years. The abandoned device was a pacemaker in 13 (77%), and a defibrillator in 4 (24%). The new device was a pacemaker in 2 (12%) and defibrillator in 15 (88%). The most common indication for contralateral placement was occluded veins, in 14 (82%) patients. Follow up was 3.7 ± 3.5 years; over this time, 6 patients had end-of-life reached on the abandoned device; device output was set to minimal voltage and pulse width. Three were Medtronic pacemakers that self-reverted to VVI 65. This caused interference with a CRT in one patient, necessitating explant of the abandoned device. In the second patient, the new device was programmed at VOO 80bpm to overcome the abandoned device. In the last patient, the abandoned device did not capture the myocardium at minimal output settings. In the remainder of the patients, no device interference was found; one additional patient had abandoned CIED removed for discomfort. CONCLUSION We found that abandoning devices is feasible and safe in the long-term, and can be used to avoid the risks incurred by device explant. Careful attention should be paid to end-of-life behaviour of certain abandoned devices and necessary programming to prevent interaction.