Ventricular arrhythmia burden and implantable cardioverter‐defibrillator outcomes in transthyretin cardiac amyloidosis

Background As targeted treatments for amyloid transthyretin cardiomyopathy (ATTR‐CM) are becoming available, we aim to characterize the rates of ventricular arrhythmias (VAs), implantable cardioverter‐defibrillator (ICD) utilization, and their impact on survival. Methods This is a retrospective cohort study of 130 patients with ATTR‐CM diagnosed at Emory University's Cardiac Amyloidosis Center between April 2012 and September 2020. VAs were defined as nonsustained or sustained ventricular tachycardia and ventricular fibrillation. Results Of 130 patients, 42 had wild‐type disease (wtATTR) and 88 had hereditary variants (hATTR), most commonly Val122Ile (89%). At ATTR‐CM diagnosis, 80 (62%) patients had EF ≤ 40% consistent with systolic heart failure. Of the 69 (53%) patients with documented VAs significantly higher rates occurred among those with EF ≤ 40% compared with EF > 40% (67% vs. 28%, p = .001). Thirty‐two patients (25 hATTR, 7 wtATTR) had primary prevention ICDs implanted. Eight (25%) of these patients received appropriate ICD therapy while two (6%) experienced inappropriate therapy. Comparing patients with EF ≤ 35% with and without ICDs did not reveal any survival difference (3.3 ± 0.5 vs. 2.8 ± 0.4 years, p = .699). Conclusions High rates of VAs and appropriate ICD therapy were found among a unique cohort of largely hereditary ATTR‐CM patients with a high rate of systolic heart failure.