Patients with cardiac amyloidosis have a higher risk of death one year after ICD implantation compared with patients with other nonischemic cardiomyopathies (NICMs), according to a study published Sept. 1 in the Journal of the American Heart Association.

Angela Y. Higgins, MD, et al., used data from ACC's ICD Registry to compare the mortality risk after ICD implantation in patients with cardiac amyloidosis vs. NICMs. The researchers also looked at factors associated with one-year mortality in patients with cardiac amyloidosis. A total of 472 patients with cardiac amyloidosis were propensity matched with 2,360 patients with NICMs. Patients were matched based on sex, age and propensity score. The propensity score model considered congestive heart failure, NYHA class, syncope, family history of sudden death, ventricular tachycardia, cerebrovascular disease, diabetes, dialysis, chronic lung disease, hypertension, left ventricular ejection fraction, creatinine, and ICD indication (primary or secondary prevention).

Overall, patients were an average age of 68 years, and 22.7% were female. The most common ICD indication was primary prevention. At baseline, patients with cardiac amyloidosis were more likely to have a history of primary ventricular tachycardia and third-degree heart block.

Among patients with cardiac amyloidosis, the one-year mortality rate was 26.9% vs. 11.3% among patients with NICMs. The difference in mortality began immediately after ICD implantation and progressively widened over time. After adjusting for factors associated with death, cardiac amyloidosis was associated with a significant increased risk of mortality compared with NICMs (hazard ratio [HR], 1.80; 95% confidence interval [CI], 1.56-2.08). In patients with cardiac amyloidosis, factors that were significantly associated with mortality included syncope (HR, 1.78; 95% CI, 1.22-2.59), ventricular tachycardia (HR, 1.65; 95% CI, 1.15-2.38), cerebrovascular disease (HR, 2.03; 95% CI, 1.28-3.23), diabetes (HR, 1.55; 95% CI, 1.05-2.27), creatinine of 1.6 to 2.5 g/dL (HR, 1.99; 95% CI, 1.32-3.02), and creatinine >2.5 g/dL (HR, 4.34; 95% CI, 2.72-6.93).

According to the researchers, the study demonstrates significantly increased mortality one year after ICD implantation in patients with cardiac amyloidosis vs. NICMs and indicates several risk factors for one-year mortality among patients with cardiac amyloidosis and an ICD. The findings "offer important information for physicians and patients when deciding whether to place an ICD in those with cardiac amyloidosis and a clearer sense of prognosis in the years after implantation," they conclude.

Clinical Topics: Arrhythmias and Clinical EP, Cardiovascular Care Team, Heart Failure and Cardiomyopathies, SCD/Ventricular Arrhythmias, Acute Heart Failure

Keywords: Stroke Volume, Renal Dialysis, Ventricular Function, Left, Amyloidosis, Tachycardia, Ventricular, Cardiomyopathies, Death, Sudden, Heart Failure, National Cardiovascular Data Registries, ICD Registry, Creatinine

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