Association Between Extreme Heat and Increased Risk of Atrial Arrhythmias in CIED Patients

 High temperatures, especially above 100°F, appear to elevate the risk of atrial arrhythmias in patients with cardiac implantable electronic devices (CIED).

The likelihood of atrial fibrillation (AF) or atrial tachycardia (AT) begins to increase significantly at 86°F compared to a baseline of 66°F.

Odds ratios for AF/AT episodes were 2.24 or higher when temperatures exceeded 100°F, according to a recent study.

The research was presented as a digital poster at the American Heart Association (AHA) 2024 Scientific Sessions.

For ventricular arrhythmias, the study found no clear link with hot temperatures but hinted at a potential connection with extreme cold.

This study is considered the largest to date examining the relationship between environmental exposures and arrhythmias, spanning over 100 US cities.

Despite the lack of definitive evidence, researchers advocate for a precautionary approach, advising high-risk individuals to take shelter during extreme heat.

As global temperatures rise due to climate change, the problem of temperature-related arrhythmias may worsen.

Extreme heat could emerge as a novel risk factor for atrial arrhythmias, alongside established risks like smoking and alcohol use.

Further research is required to understand the mechanisms and effective clinical interventions for managing these risks.

Impact of Hot Weather on Cardiovascular Health

Previous studies link high temperatures to adverse cardiovascular health, including an excess of cardiovascular-related deaths.

Researchers examined the effect of temperature on atrial arrhythmia risk using data from Medtronic’s Product Surveillance Registry.

The study analyzed data from 3,079 patients with implantable cardioverter-defibrillators (ICDs) or cardiac resynchronization therapy-defibrillators (CRT-Ds).

Arrhythmia episodes were matched with ambient temperature recordings from the nearest meteorological stations.

The odds of AF/AT episodes increased significantly at higher temperatures:

• 86°F (OR 1.33)
• 102.2°F (OR 2.41)
• 104°F (OR 2.60)
• 107.6°F (HR 3.03)

Potential explanations include increased core body temperature, dehydration, and loss of electrolytes such as magnesium and potassium.

Hot weather can also raise heart rate, which, combined with electrolyte loss, may trigger arrhythmias.

Implications for Vulnerable Populations

The findings highlight the need for further studies involving broader populations, including those without implanted devices and vulnerable communities.

Experts recommend guidance for at-risk groups to avoid high-temperature environments, such as seeking air-conditioned shelters.

Cities and communities should prioritize measures to protect individuals during extreme heat.

Take-Home Points

1. Extreme heat raises the risk of atrial arrhythmias in CIED patients, particularly above 100°F.
2. Odds of arrhythmias increase significantly starting at 86°F.
3. Hot weather may trigger arrhythmias through dehydration and electrolyte imbalance.
4. Precautionary measures, such as staying in air-conditioned spaces, are advised for high-risk groups.
5. Climate change could exacerbate temperature-related cardiovascular risks, emphasizing the need for proactive strategies.