Abstract 2976: Implantable Cardioverter Defibrillator Therapy in Cardiac Amyloidosis: Mayo Clinic Experience
Background: Patients with cardiac amyloidosis are at risk for ventricular arrhythmias and sudden cardiac death. However, the benefit of ICD implantation in patients with cardiac amyloidosis is not well defined. We describe our single center experience with ICD therapy in cardiac amyloidosis.
Methods: All patients with cardiac amyloidosis who underwent ICD implantation and were evaluated at the Mayo Clinic, Rochester, MN from 2000–2005 were included. Implant indications, frequency of ICD therapy, and clinical /pathological data were obtained from the medical record. Appropriate ICD therapies were defind as those treating ventricular arrhythmias. Inappropriate ICD therapies were defined as those triggered by sinus tachycardia, atrial fibrillation, or device malfunction. Survival and rates of ICD therapies were determined with Kaplan Meier survival curves.
Results: Of 25 patients in the study group, 18 (72%) received an ICD for primary prevention, 3 (12%) patients had a cardiac arrest, and 4 (16%) patients had sustained ventricular tachycardia. Mean age was 64 ± 11 years, with 18 (72%) males. The underlying amyloid disease was AL amyloidosis in 17 (68%) patients, senile amyloidosis in 5 (20%) patients, and familial amyloidosis in 3 (12%) patients. Ejection fraction, creatinine and defibrillation threshold at the time of implantation were 50% ± 16%, 1.64 ± 0.87 g/dL, and 19 ± 6 J, respectively. ICD therapy records were available for 14 patients. Over the follow up period of 11 ± 16 months, 4 (16%) patients had appropriate ICD therapies and 1 (4%) patient had an inappropriate shock due to device malfunction. Survival at one year in the study group was 65%, with 2 patients receiving cardiac transplants, and 12 deaths, from heart failure (1), asystolic cardiac arrest (1), pulseless electrical activity (2), renal failure (1), and sepsis (1). The rate of appropriate ICD discharges at one year was 42%.
Conclusions: Rate of appropriate ICD discharge in patients with cardiac amyloidosis is high, but may not improve overall mortality. These data support the notion that mortality benefit of ICD therapy in patients with cardiac amyloidosis is limited.