In a new study, researchers found that heart drugs used to treat irregular heartbeat are less effective in patients who are obese.
The research was conducted by a team at the University of Illinois at Chicago.
Atrial fibrillation, also known as AFib, is the most common type of irregular heartbeat, and it is associated with increased mortality.
While researchers have identified a causal link between obesity and AFib, the underlying mechanism of how obesity contributes to heart arrhythmia is still unknown.
According to the team, response to current antiarrhythmic drug treatment for AFib is highly variable and unpredictable, and medication selection depends on the treating physician.
There are no guidelines to suggest whether Class I drugs — which work on sodium channels in the heart to regulate heartbeat — or Class III drugs –those that target potassium channels — work best in which patients.
Previously, it was assumed that both antiarrhythmic drugs were equally effective in preventing reoccurrences of AFib.
In the new study, the team tested more than 300 patients found that Class I drug treatment showed increased rates of AFib reoccurrences in obese patients compared with non-obese patients — approximately 30% of obese patients had AFib reoccurrence, compared with only 6% of non-obese patients.
This effect was not seen among patients treated with Class III drugs. Similar results were replicated in a study of obese and non-obese mice.
This study is the first showing that there is a differential response to antiarrhythmic drugs for AFib
It provides new information that physicians can use to guide their decisions for obese patients with AFib.
The researchers ultimately hope to uncover the underlying mechanism of how obesity hinders Class I antiarrhythmic drugs and find new and targeted AFib treatment options.
One author of the study is UIC’s Dr. Dawood Darbar.
The study is published in JAMA Cardiology.
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