First-degree Atrioventricular Block as an Early Marker of Advanced Disease of the Conduction System in a Patient with Hereditary Val142Ile Cardiac Amyloidosis

Introduction

Cardiac amyloidosis (CA) is a type of restrictive cardiomyopathy secondary to amyloid infiltration in the heart. The most common clinical forms are immunoglobulin light chain amyloidosis (AL) and amyloidosis resulting from amyloid deposits secondary to the destabilization of the protein tetramer transthyretin (ATTR), which is divided into two types: the hereditary form (ATTRm) and the wild type (ATTRwt).

Cardiac impulse conduction disorders and atrial arrhythmias are more frequent in ATTR than in the AL form, and this seems to reflect the longer survival of patients affected by ATTR, given that the AL form manifests with high mortality up to 6 months from diagnosis, because conduction system disease appears to be a later manifestation.

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