Abstract P113: Increased Incidence of Atrial Fibrillation During Periods of High Influenza Activity

Introduction: Influenza is an important inflammatory illness which results in 3 to 5 million cases of severe illness, and 290,000 to 650,000 deaths per year, worldwide. Influenza’s role in triggering acute coronary syndromes is well established, but influenza’s impact on cardiac arrhythmias has yet to be investigated. Hypothesis: We investigated the effect of influenza on triggering atrial fibrillation (AFib) episodes. Methods: This retrospective observational study included de-identified data from patients who had a Zio patch (iRhythm Technologies, San Francisco), a wearable continuous cardiac monitoring device. Data were available from October 2012 to September 2017. The “influenza activity” was defined as the percentage of positive respiratory specimens that tested for influenza virus during each influenza season reported by the Centers for Disease Control and Prevention (CDC). We included all cases with AFib burden <=90% from the weeks with the highest and lowest influenza activity up to two consecutive weeks after them. An independent-samples t-test was used to compare the burden of AFib in weeks with the highest and lowest influenza activity. Results: We reviewed the records of 825,869 patients (mean age= 61.1 ± 15.3 years; 48.8% male) who had a Zio patch from October 2012 to September 2017. Of these patients, 47,106 met the pre-defined inclusion criteria for our study. There was a significant difference in the AFib burden in high influenza activity (Mean=1.19, SD=0.69) and low influenza activity (Mean=1.03, SD=0.63) conditions; t (47104) = -2.6, p =0.009. The incidence of AFib was 15% higher in high influenzas activity weeks (OR=1.15, 95%CI, 1.03-1.19, p=0.009). The higher burden of AFib in high influenza activity weeks was significant for each influenza season and a similar trend was observed consistently in each individual influenza season. Conclusions: High seasonal influenza activity is associated with increased odds of AFib. Prospective studies are needed to determine the clinical implications of this finding.