Introduction:
Implantable cardioverter defibrillator (ICD) implantation in patients with cardiac amyloidosis is controversial, with no clear guidelines for clinical decision-making.. The role of ICD implantation in hereditary Transthyretin Amyloid Cardiomyopathy (hATTR-CM) is unclear. We sought to establish the burden of ventricular arrhythmias and the outcomes of ICD implantation in a single center cohort of hATTR-CM patients.
Methods:
A total of 69 patients with a confirmed diagnosis of hATTR-CM from genetic testing, and technetium pyrophosphate (PYP) scanning, or endomyocardial biopsy underwent retrospective chart review for demographic, clinical, and arrhythmia data.
Results:
Seventy-four percent of the cohort was male, with a mean age at diagnosis of 68 (SD=18 years). Sixty-five patients (94.2%) patients were African-American; all of whom carried the Valine 122 Isoleucine mutation. Most had systolic heart failure (New York Heart Association Staging II [18, 26%] and III [40, 58.8%]); 37 (54%) patients had an LVEF ≤ 35%. Thirty-six (52.2%) patients had documented episodes of non-sustained ventricular tachycardia (NSVT), three (4.3%) with ventricular tachycardia (VT), and one (1.5%) with ventricular fibrillation (VF). A total of 15 (21.7%) patients had ICDs placed for prevention of sudden cardiac death in the setting of low LVEF (EF <35%). All recorded VT/VF episodes occurred in three patients with ICDs. Of these patients, one experienced two episodes of VT each successfully abated by antitachycardia pacing (ATP), another experienced a single episode of VT abated by ATP, while the final experienced VF with successful 36J shock as well as two episodes of VT each successfully treated with 36J shocks. No inappropriate ICD shocks were delivered, however, there were two instances of ATP for inappropriately detected atrial arrhythmias.
Conclusions:
In a cohort of patients with hATTR-CM, we observed a high incidence of NSVT, yet only 41% of patients with severe systolic heart failure had ICDs implanted. A high rate of successful defibrillation and no inappropriate ICD shocks were noted, suggesting that ICDs should be strongly considered, and may be underutilized, in patients with systolic heart failure and/or arrhythmias in the setting of hATTR-CM.
A Novel Low-Energy Electrotherapy That Terminates Ventricular Tachycardia With Lower Energy Than a Biphasic Shock When Antitachycardia Pacing Fails
