Syncope and Rhythm Disturbances as Common Clinical Manifestations in Amyloidosis

Abstract

Amyloidosis results from deposition of insoluble fibrillar protein compounds in various organs, including the heart. Cardiac involvement occurs in both atria and ventricles, leading to restrictive cardiomyopathy, heart failure (HF), and arrhythmias. Five amyloid proteins affect cardiac tissue: light and heavy chain forms of immunoglobulin, transthyretin (TTR), apolipoprotein 1, and amyloid A. Approximately 95% of cardiac involvement stems from light chain of immunoglobulin and TTR deposition in heart. Chamber stiffness and rhythm disturbances occur in cardiac amyloidosis (CA), encompassing from HF to atrial and ventricular arrhythmias (VA), and both can compromise each other. It is known that conduction system disorders and VA increase sudden death risk, as amyloid infiltration, inflammation, and fibrosis alter myocardial electrophysiology. Beyond the heart, autonomous nerve systems suffer amyloid deposition, contributing to syncope manifestation and increasing the risk of death and poor prognosis. In this context, our review sheds light on the importance of recognizing syncope and rhythm disturbances as crucial markers in the early identification and management of CA, potentially offering avenues for prompt intervention and improved patient outcomes.