New-Onset Atrial Fibrillation in Patients With Coronavirus Disease 2019 (COVID-19) and Cardiovascular Disease ― Insights From the CLAVIS-COVID Registry ―

Background: Both pre-existing atrial fibrillation (AF) and new-onset AF (NOAF) are observed in patients with coronavirus disease 2019 (COVID-19); however, the effect of AF on clinical outcomes is unclear. This study aimed to investigate the effect of AF, especially NOAF, on the outcomes of hospitalized patients with COVID-19. Methods and Results: This study analyzed 673 COVID-19 patients with cardiovascular diseases and risk factors (CVDRF). Patients were divided into 3 groups; pre-existing AF (n=55), NOAF (n=28), and sinus rhythm (SR) (n=590). The baseline characteristics and in-hospital outcomes were evaluated. The mean age of the patients was 68 years, 65.4% were male, and the in-hospital mortality rate was 15.6%. The NOAF group demonstrated a higher in-hospital mortality rate (42.9%) than the pre-existing AF (30.9%) and SR (11.2%) groups (P<0.001). Patients with NOAF had a higher incidence of acute respiratory syndrome, multiple organ disease, hemorrhage, and stroke than those with pre-existing AF and NOAF. NOAF was independently associated with in-hospital mortality after adjusting for pre-existing AF and 4C mortality score (odds ratio [95% confidence interval]: 4.71 [1.63-13.6], P<0.001). Conclusions: Patients with NOAF had significantly worse outcomes as compared to patients with pre-existing AF and SR. The incidence of NOAF would be a useful predictor of clinical outcomes during hospitalization.