Atrial fibrillation (AF) is a condition characterized by irregular rhythm of the heartbeat. A new study has revealed that cold weather is associated with increased risk of ischemic stroke in patients with AF.
Researcher Tze-Fan Chao, cardiologist at National Yang-Ming University in Taiwan, said, "Our study shows a clear association between temperature and risk of ischemic stroke in patients with AF. The findings indicate that cold climates may promote the formation of blood clots within the left atrium and increase the risk of stroke for AF patients. Risk may increase in cold weather because of the pro-coagulant status."
For the study, researchers followed 289,559 new-onset AF patients from the 'National Health Insurance Research Database' in Taiwan during 2000 to 2011. Among the Taiwan AF cohort, 34,991 patients suffered from an ischemic stroke during the mean follow up period of three years. It was observed that the risk of ischemic stroke was higher among the months with a lower average temperature. In addition, the incidence of ischemic stroke was highest in winter and lowest in summer. Compared to summer, the risk of ischemic stroke increased by 10% in spring and 19% in winter. Stroke risk did not differ significantly between summer and autumn.
The study findings were presented at European Society of Cardiology (ESC) Congress 2015 in London.