Temperatures above 100°F could triple atrial fibrillation episodes in people with defibrillators
Temperatures of 100°F (38°C) or higher could nearly triple the odds of experiencing an atrial fibrillation episode in people with implantable cardioverter defibrillators.
Certain factors, such as heart disease and other medical conditions, are known to increase the risk of atrial fibrillation (AFib); however, little is known about the role of heat-induced stress in triggering this condition. Now, preliminary research to be presented at the American Heart Association’s Scientific Sessions 2024 (16–18 November; Chicago, IL, USA) led by Barrak Alahmad (Harvard T.H. Chan School of Public Health; MA, USA) has found that exposure to temperatures of 100°F (38°C) or higher may nearly triple the number of episodes of AFib in people with implantable cardioverter defibrillators.
AFib is an irregular heart rhythm condition, which is associated with an increased risk of heart failure, stroke and dementia. With the global incidence of AFib rising at an alarming rate, researchers are looking to better understand the condition and the factors that influence it. Heart disease and other conditions are known to increase the risk of AFib, but the effect of temperature on the condition is currently understudied.
To address this, a collaboration of researchers analyzed data from over 2000 people who had an implanted cardioverter defibrillator or cardiac resynchronization therapy defibrillator device implanted between 2016 and 2023 across more than 100 cities in the US. They matched the first episode of AFib detected by the device to the hourly outdoor temperature data from the day of the episode, in the respective locations where the devices were implanted.
They found that outdoor temperatures between 41°F and 46.4°F (5°C to 8°C) had the lowest odds of causing an AFib episode, while higher temperatures of 102.2°F, 104°F and 105.8°F (39°C, 40°C and 41 °C) increased the odds of experiencing an episode by 2.66, 2.87 and 3.09 times, respectively. Their analysis also revealed that more AFib episodes occurred during standard working hours (8am–5pm) than early morning hours (12am–7am), and episodes were more common on weekdays than weekends.
“We need to understand the physiological processes underlying these findings and concentrate on preventing conditions that trigger AFib to minimize the burden of arrhythmias,” commented co-author Theofanie Mela (Massachusetts General Hospital; MA, USA). “In the meantime, we recommend patients avoid extreme temperatures and use air conditioners so that they do not expose their bodies to the severe stress of extremely high heat.”
While more research will be needed to draw definitive conclusions, such research is important as climate change begins to bring higher temperatures.
