Characteristics of the two groups.

Background
COVID-19, a highly infectious respiratory disease, has been associated with a range of cardiovascular complications. One of the most commonly reported cardiovascular issues in COVID-19 patients is the development of arrhythmias. Among all types of arrhythmias, atrial fibrillation is the most frequently observed. Atrial fibrillation is characterized by an irregular and often rapid heartbeat, and it can be a serious and potentially life-threatening condition.
Objective
To investigate the incidence and association of new onset atrial fibrillation in COVID-19 hospitalized patients and its impact on survival.
Method
A retrospective cross-sectional study that encompassed all patients, both positive and negative for COVID-19, who were consecutively admitted to the Aga Khan University Hospital in Karachi, a tertiary care facility, from June 2021 to December 2021.
Results
A total of 1,313 patients who met the inclusion criteria of our study were enrolled as participants. These patients were then stratified into two groups based on COVID-19 status: the study group (COVID-19 positive) comprised 626 (47.7%) patients and the control group (COVID-19 negative) consisted of 687 (52.3%) patients. The incidence of new-onset atrial fibrillation was 85 (13.6%) in COVID-19 positive compared to 43 (5.2%) in COVID-19 negative group. The study found a strong association between COVID-19 and new-onset atrial fibrillation in both univariate (unadjusted odd ratio 2.35 [95% CI, 1.60–3.45], p-value < 0.01) and a multiple-adjusted regression analysis (adjusted odd ratio 3.86 [95% CI, 2.31–6.44], p-value < 0.01).
Conclusion
These findings highlight the importance of vigilant monitoring of cardiovascular complications in COVID-19 patients, especially those with pre-existing conditions that predispose them to the development of atrial fibrillation. The study underscores the need for prompt recognition and management of new onset atrial fibrillation in COVID-19 patients, as this may mitigate the risk of adverse outcomes and improve overall prognosis.