Arrhythmias in Cardiac Amyloidosis: Challenges in Risk Stratification and Treatment

Abstract

Cardiac amyloidosis occurs secondarily to the deposition of insoluble protein fibrils in cardiac tissue leading to progressive myocardial dysfunction, clinical heart failure, and arrhythmia. In recent years, increasing awareness and improved screening have resulted in an increased prevalence of cardiac amyloidosis, with contemporary estimates reporting a prevalence of 18-55 cases per 100,000 person-years, accounting for > 13% of heart failure hospitalizations. The arrhythmic manifestations of cardiac amyloidosis can range from conduction-system disease and bradyarrhythmias to atrial fibrillation and sudden cardiac death. Bradyarrhythmias and conduction system disease may occur secondarily to amyloid infiltration, but the timing of pacemaker implantation remains unclear. When available, biventricular pacing should be considered in symptomatic patients, particularly in those expected to receive a high burden of ventricular pacing (> 40%). The management of atrial fibrillation can be challenging, because contemporary agents for rate and rhythm control may be poorly tolerated in patients with cardiac amyloidosis. Patients with cardiac amyloidosis also have a high rate of intracardiac thrombus and should be anticoagulated in the presence of atrial fibrillation (regardless of CHADS₂ score). We generally consider transesophageal echocardiography before cardioversion regardless of anticoagulation status or duration of arrhythmia. Ventricular arrhythmias may also occur in patients with cardiac amyloidosis, and decisions surrounding implantable cardioverter-defibrillator implantation should balance the risks of ventricular arrhythmia and sudden cardiac death with the competing risks of worsening heart failure and noncardiac death. In this review, we cover the primary arrhythmic manifestations of cardiac amyloidosis and discuss their management considerations.