Complications involving the subcutaneous implantable cardioverter-defibrillator: Lessons learned from MAUDE.

BACKGROUND: Reports on the subcutaneous implantable cardioverter-defibrillator (S-ICD) cumulatively demonstrate a low rate of complications, but clinical experience with this technology is limited compared with transvenous devices.
OBJECTIVE: The purpose of this study was to describe and analyze S-ICD complications reported to the Food and Drug Administration's Manufacturer and User Facility Device Experience database.
METHODS: We reviewed all S-ICD events reported to the Manufacturer and User Facility Device Experience submitted over 24 months (from February 2016 through February 2018) through a prospective and standardized approach at a time when an estimated 15,000 S-ICDs were in service.
RESULTS: After removing duplicate entries and nonclinical events (n = 493), 1604 events remained. A total of 542 instances of infection were reported with system removal in 414/542 (77.5%). Inappropriate shocks occurred in 550 patients, and 382 (69%) were attributed to oversensing; in response, 254 (56%), 147 (33%), and 80 (18%) patients underwent system reprogramming, removal, or revision, respectively. There were 15 deaths, and causes included defibrillation failure during follow-up (n = 2), ventricular fibrillation induced by the device (n = 4), device-device interaction resulting in undersensing (n = 1), procedure-related complications (n = 4), and uncertain etiology (n = 4). There were 137 reports of system migration, and in 57 (42%) of these, there were associated inappropriate shocks. System migration events were managed with a combination of system revision (69 [51%]), reprogramming (25 [18%]), and system removal (44 [32%]).
CONCLUSION: Several S-ICD complications have been reported that appear to be related to the ICD's design and function over time. A better understanding of these complications may help inform patient selection, implant technique, and postimplantation management.