Prevalence and Impact of Arrhythmia on Outcomes in Restrictive Cardiomyopathy-A Report from the Beijing Municipal Health Commission Information Center (BMHCIC) Database

Background: Data on the outcomes of restrictive cardiomyopathy (RCM) are limited, when the condition is complicated with arrhythmia. This study was designed to investigate the prevalence of atrial fibrillation (AF), ventricular tachycardia (VT) and bradycardia (BC) and their impact on adverse outcomes (intra-cardiac thrombus, stroke and systematic embolism [SSE], heart failure and death) of RCM. Methods and Results: The retrospective cohort study used data collected from the Beijing Municipal Health Commission Information Center (BMHCIC) database from 1 January 2010 to 31 December 2020. There were 745 (64.9%) patients with AF, 117 (10.2%) patients with VT and 311 (27.1%) patients with bradycardia. The presence of AF was associated with an increased risk of SSE (adjusted HR:1.37, 95%CI:1.02–1.83, p = 0.04) and heart failure (aHR:1.36, 95%CI:1.17–1.58, p < 0.001). VT was associated with an increased risk of intracardiac thrombus (aHR:2.34, 95%CI:1.36–4.01, p = 0.002) and death (aHR:2.07, 95%CI:1.19–3.59, p = 0.01). Bradycardia did not increase the adverse outcomes in RCM. The results remained consistent and steady when AF, VT and bradycardia were adjusted as competing factors. Conclusions: Cardiac arrhythmia are highly prevalent and associated with adverse outcomes in patients with RCM. AF and VT are more likely to be associated with intracardiac thrombosis, and the presence of AF increased the risk of SSE and HF. The presence of VT increased the risk of death.