Abstract 9977: Concerns Raised Around Adverse Event Reporting Associated with the Subcutaneous Implantable Cardioverter Defibrillator Device

Abstract

Objective: To review adverse events reports for the subcutaneous implantable cardioverter defibrillator (S-ICD) device and understand challenges in its application. Background: The S-ICD is an increasingly popular alternative to transvenous ICD (TV-ICD) devices since FDA approval in 2012. Although we have the benefit of professional guidelines, there are no high-quality trials showing mortality benefit. There are concerns about higher rates of inappropriate shocks with use of S-ICD, which prompted a ‘Smartpass’ firmware upgrade in 2016. The impact of this upgrade on rates of inappropriate shocks remains ill-defined. Methods: Narrative reports of adverse events associated with the S-ICD reported to the FDA MAUDE database were reviewed for reason for reporting and outcomes. These were compared with the total number of devices found on shareholder reports as of October 2020. Results: Of 35,000 S-ICD devices in the US, 9,349 adverse events and 2,521 inappropriate shocks were reported in MAUDE. There were 108 deaths, 21 of which were due to a failure to convert a ventricular arrhythmia. Rates of inappropriate shocks comprised an increasing proportion of adverse events year over year with no decline following the ‘Smartpass’ upgrade. Conclusion: The multiple instances of death following S-ICD failure are alarming as these fatal events are thought to be rare for TV-ICDs. Additionally, even with the introduction of Smartpass, inappropriate shocks have not declined. These findings, taken in conjunction with the lack of data for mortality benefit of the S-ICD and safety concerns surrounding the recent lead recall, should be considered by clinicians in future decisions about S-ICD use.