957 EMERGING FROM THE DARKNESS. SUDDEN CARDIAC DEATH IN CARDIAC AMYLOIDOSIS

Abstract

Abstract Cardiac amyloidosis (CA) manifests as infiltrative cardiomyopathy with a hypertrophic pattern, usually presenting with heart failure with preserved ejection fraction (HFpEF). In addition, degenerative valvular heart disease, particularly severe aortic stenosis, is commonly seen in patients with CA. However, amyloid fibril deposition may also infiltrate the conduction system and promote the development of electrical disorders, including ventricular tachyarrhythmias (VT), atrio-ventricular block, or acute electromechanical dissociation (EMD). These manifestations can increase the risk of sudden cardiac death (SCD). This review summarizes the pathophysiological mechanisms and risk factors for sudden cardiac death in cardiac amyloidosis and focuses on the major current concerns regarding medical and device management in this challenging scenario. Heart involvement is the major determinant of survival in patient with amyloidosis and a “sudden death” occurs in approximately two-thirds of patients with cardiac amyloidosis. Moreover, the AL amyloid fibrils are shown to be highly cytotoxic to the ventricular myocardial, explaining why ventricular arrhythmias appear more frequently in AL over ATTR. Proposed mechanisms driving electrophysiological manifestations of CA involve intramural coronaries, microvascular ischemia, or patchy myocardium infiltration of amyloid fibrils, causing the development of anatomical re-entrant circuits responsible for ventricular arrhythmia. The prevalence of non-sustained ventricular tachycardia (NSVT) in AL amyloidosis ranges from 5 to 27% with routine monitoring and 100% during the stem cell transplant period. The guidelines don't provide specific indications regarding insertion of implantabile cardioverter defibrillator (ICD) and they don't clarify whether some patients subtypes can benefit from them. Amyloid infiltration into the conduction system enhances the genesis of rhythm disturbances, including fatal ventricular arrhythmias and SCD. Current pharmacological anti-arrhythmic therapies are poorly tolerated in CA, and there are no robust recommendations on the management of ventricular arrhythmias in this subset of patients. Furthermore, the benefit of ICD implantation is highly variable according to the different clinical stages of the disease. Therefore, further studies are needed to create a standardized diagnostic algorithm and appropriate treatment strategy for this special population.