Admissions to the Emergency Department Due to Atrial Fibrillation/Atrial Flutter Incidents during the Third Wave of COVID-19 Pandemic.

(1) Background: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection increases the risk of atrial fibrillation/flutter (AF/AFL) incident. The study aimed to present the characteristics of admissions to the emergency department (ED) due to AF/AFL incidents during the third COVID-19 pandemic wave. (2) Methods: A retrospective analysis of the medical records of the ED patients: 8399 during 3 months of the second and 11,144 during the 3 months of the third pandemic wave. (3) Results: SARS-CoV-2 positive patients there were 295 (3.5%) during the second wave and 692 (6.2%) during the third wave (p < 0.001). Among patients with SARS-CoV-2 infection, there were 44 (14.9%) patients with known AF/AFL during the second wave and 75 (10.8%) during the third wave, respectively (0.07). There were 116 visits with a diagnosis of AF/AFL incident during the third wave (study group) and 76 visits during the second wave (control group). The SARS-CoV-2 test was positive in 11 (9.5%) visits in the study group and in 1 (1.3%) visit in the control group p = 0.047. During the third wave, the patients with AF/AFL incidents with positive tests were older and more often had new-onset AF/AFL than those with negative tests: 76.3 (13.2) years vs. 71.8 (12.6) years; and 4 (36.4%) patients vs. 7 (7.6%) patients, respectively. (5) Conclusions: During the third pandemic wave, the number of patients with SARS-CoV-2 infection increased in comparison to the second wave. Additionally, among patients with AF/AFL incidents, the percentage of SARS-CoV-2-positive patients increased. During the third wave, the patients with positive tests and AF/AFL incident were older and more often had new-onset AF/AFL than those with AF/AFL incident and negative test which indicate the arrhythmogenic effect at the onset of the disease, especially in the older population.