Incidence and implications of atrial fibrillation in patients hospitalized for COVID compared to non-COVID pneumonia: A multicenter cohort study

BACKGROUND: Atrial fibrillation (AF) has been reported to occur with coronavirus disease 2019 (COVID-19), but whether it is related to myocarditis or lung injury is unclear. OBJECTIVES: The purpose of this study was to compare incident AF in patients with pneumonia/adult respiratory distress syndrome (ARDS) with and without COVID. METHODS: This retrospective multicenter cohort study from 17 hospitals (March 2020 to December 2021) utilizing the University of California COVID Research Data Set (CORDS) included patients aged ≥18 years with primary diagnosis of pneumonia or ARDS during hospitalization. Patients with a history of AF were excluded. All subjects had documented COVID test results. Cohorts were compared using the χ(2) test for categorical variables and the Wilcoxon rank test for continuous variables. Multivariable logistic regression models were used to investigate the association between COVID and development of new AF. RESULTS: Of the 39,415 subjects, 12.2% had COVID. The COVID+ cohort consisted predominantly of younger males with more comorbidities. Incident AF was lower in the COVID+ group than in the non-COVID group (523 [10.85%] vs 4899 [14.16%]; odds ratio [OR] 0.74; P <.001), which remained significant after adjustment for demographics and comorbidities (OR 0.71; P <.001). Patients had normal cardiac troponin levels. AF was related to intensive care unit care, pressor support, and mechanical ventilation, and was associated with higher mortality (26.2% vs 10.21%; P <.001) and longer hospitalization (22.5 vs 15.1 days; P <.001) in the COVID+ group compared to the controls. CONCLUSION: Incident AF is lower in COVID+ compared to non-COVID pneumonia/ARDS patients and seems to be related to severity of illness rather cardiac injury. AF was associated with higher mortality and prolonged hospitalization.