Mode of death and outcomes of implantable cardioverter defibrillators in transthyretin amyloid cardiomyopathy

Introduction: Transthyretin cardiac amyloidosis (ATTR-CM) may associate with sudden cardiac death. We report on the mode of death and outcomes with implantable cardioverter defibrillators (ICDs) in a cohort with ATTR-CM. Methods: A single center observational cohort study of patients with ATTR-CM diagnosed between 2005 and 2019. ICD implant was at discretion of treating cardiologists. Medians are expressed with 25th,75th percentiles. Results: Eighty-four patients with ATTR-CM (age 73.5 ± 9.7 years, 94% male, median follow-up 21.1 months (11.4–38.1). Nineteen patients (23%) underwent ICD implantation – 18 for primary and 1 for secondary prevention. In the primary prevention ICD group, 1 patient had 2 inappropriate shocks, 1 patient had appropriate ATP on 3 occasions. One patient (mixed ischemic cardiomyopathy and ATTR-CM) with secondary prevention ICD had 15 appropriate shocks in 3 episodes of VT storm. In patients without ICD, ambulatory monitoring review (14,764 h) did not reveal sustained ventricular arrhythmia. Excluding the one patient with secondary prevention ICD, 5 (28%) in the primary prevention ICD group and 22 (34%) in the non-ICD group died, p = 0.14. Mode of death did not vary between both groups. Conclusions: Patients with ATTR-CM and primary prevention ICD infrequently receive appropriate device therapy without differing in mode of death, which was mainly related to progressive heart failure, compared to those without ICD.