The burden of atrial fibrillation and its prognostic value in patients with dilated cardiomyopathy.

Background: Atrial fibrillation (AF) is the most common arrhythmia in patients with dilated cardiomyopathy (DCM). However, the epidemiology as well as clinical and prognostic significance of AF in DCM are poorly defined.

Aims: We aimed to assess the impact and prognostic value of AF in DCM as well as to investigate the concept of AF‑induced DCM.

Methods: Hospital records of 285 patients with DCM from 2012 to 2018 with follow-up were analyzed.

Results: Atrial fibrillation was present in 89 patients (31%). They were older, more frequently male, hadhigher body mass index, New York Heart Association class, heart rate (HR), creatinine levels, and larger atria (all P < 0.05) than patients without AF. During follow‑up (mean [SD], 35 [24] months), death occurred in 20 of the 82 available patients with AF and 22 of the 188 patients without AF (24% and 12%, respectively; P = 0.007). Atrial fibrillation was independently associated with a worse outcome (hazard ratio, 2.4; 95% CI, 1.3-4.3) and was found to be the major cause of DCM in 21 patients (24%). The diagnostic accuracy of the most optimal predictive model for AF‑induced DCM was 0.935 (95% CI, 0.903-0.967). Despite numerical differences, survival was similar in DCM patients with and without AF (P = 0.15).

Conclusions: Almost one‑third of patients with DCM had AF. Most of the parameters analyzed differed between patients with and without AF, and AF was found to be an independent prognostic factor of DCM. One‑fourth of patients with DCM and AF met the diagnostic criteria for AF‑induced DCM.