Syncope in patients with transthyretin amyloid cardiomyopathy: clinical features and outcomes

Abstract

Background:We aimed to describe the clinical characteristics, underlying causes and outcomes of syncope in patients with transthyretin amyloid cardiomyopathy (ATTR-CM). Methods:The clinical profile and underlying causes of syncopal episodes were reviewed in a cohort of 128 patients with ATTR-CM enrolled from January 2018 to June 2020 in a prospective multicentre registry in 7 hospitals of Galicia (Spain). After enrollment, patients were followed during a median period of 520 days.The effect of syncope on all-cause mortality was assessed by means of multivariate Cox´s regression.Results: Thirty (23.4%) patients had a history of previous syncope as a clinical antecedent before being enrolled in the prospective phase of the registry, and 4 (3.1%) experienced a first episode of syncope thereafter. The estimated incidence density rate of syncope during the prospective follow-up period after registry enrollment was 71.9 episodes per 1000 patients-year (95% Confidence Interval (CI) 32.8-111.1).The estimated overall prevalence of syncope was 26.6% (95% CI 18.9%-34.2%). Cardiac arrhythmias (n = 11, 32.3%), structural diseases of the heart or great vessels (n = 5, 14.7%), a neurally mediated reflex (n = 6, 17.6%), and orthostatic hypotension (n = 4, 11.8%) were identified as probable underlying causes of syncope; in 8 (23.6%) patients, syncope remained unexplained. Patients with syncope had increased nonadjusted all-cause mortality than patients without it (univariate hazard-ratio 3.37; 95% CI 1.43-7.94). When other independent predictors of survival were added to the survival model, this association was no longer statistically significant (multivariate hazard-ratio 1.81, 95% CI 0.67-4.84).Conclusions: Syncope is frequent in patients with ATTR-CM. This study could not demonstrate an independent association between syncope and mortality in those individuals.

Cardiac Amyloidosis

“…Additionally, autonomic dysfunction in these patients is associated with decreased cardiac output. However, there is no evident association between syncopal events and mortality in ATTR patients despite frequent events and poor quality of life [37,38].…”