Monthly Variation in Emergency Department Admission for Acute Onset Atrial Fibrillation

The cold season seems to be a trigger for atrial fibrillation (AF). Some reports are controversial and demonstrate variability according to the climatic characteristics in different regions.

To analyze whether meteorological factors contribute to seasonal variation of exacerbation of AF diagnosed in patients referred to the emergency department (ED) of our hospital.

We retrospectively reviewed medical data of consecutive patients admitted to the ED with symptomatic acute onset AF from 1 January 2016 to 31 December 2018. We recorded the mean monthly outdoor temperature, barometric pressure, and relative humidity during the study period.

During the study period, 1492 episodes of AF were recorded. New onset AF were 639 (42.8%) and paroxysmal atrial fibrillation (PAF) were 853 (57.2%) (P = 0.03). The number of overall admission of AF episodes was not distributed uniformly through the year. Incidence of AF episodes peaked during December and was lowest in June (P = 0.049). Of 696 episodes (46.6 %) the patients were hospitalized and for 796 (53.4%) the patients were discharged (0.01). The number of hospitalizations was not distributed uniformly through the year (P = 0.049). The highest number of hospitalizations happened in December and the lowest in May. Outdoor temperature and barometric pressure (but not relative humidity) may mediate a monthly fluctuation in AF episodes with highest number of ED visits in December and the lowest in June.

Meteorological conditions influence exacerbation of AF episodes and hospitalization. Outdoor temperature and barometric pressure may mediate a monthly fluctuation in AF.