Overweight patients treated for a common type of irregular heartbeat are less likely to experience a relapse if they lose the extra pounds and maintain that healthier weight, two new studies suggest.
Atrial fibrillation is an irregular and often-rapid heartbeat involving the upper two chambers of the heart that leads to poor blood flow throughout the body. It can be corrected through cardiac ablation, a procedure used for abnormal heart rhythms.
But about 30 percent of patients need to have a repeat procedure to remain free of atrial fibrillation, lead researcher Dr. Jared Bunch, director of electrophysiology at the Intermountain Medical Center Heart Institute in Salt Lake City, said in an Intermountain news release.
"Both physicians and patients often ask what else can be done to make the procedure more effective, and the results from these studies give us a convincing answer," he said. Because obesity is a common cause of atrial fibrillation, according to the researchers, they decided to see what effect losing weight and maintaining that weight loss might have on controlling the irregular heart rhythm.
The first study included more than 400 patients treated with cardiac ablation for atrial fibrillation. The researchers tracked their health for three years. The study found that people who maintained their weight or gained weight were more likely to have a recurrence of atrial fibrillation. Losing at least 10 pounds and keeping it off, however, was associated with significant improvements in the success of the procedure. The researchers noted that those patients who lost weight and then gained it back had the highest relapse rates.
"This study shows one of the most powerful ways to improve outcomes after a cardiac ablation is in the patient's control," said Bunch. "As with all heart conditions, losing weight is only one piece of the puzzle. The patients also have to keep the weight off for up to a year. Patients who quickly gained the weight back or even gained more than they weighed at their ablation had the worst outcomes."
For the second study, the same researchers followed more than 1,500 patients for three years. They separated them into four groups based on their body mass index (BMI) -- a rough estimate of a person's body fat based on height and weight measurements. The first group was comprised of participants with a BMI of less than 20 (underweight). Those in the second group had a BMI of 21 to 25 (normal weight) while those in the third group had a BMI of 26 to 30 (overweight). People in the fourth group had a BMI greater than 30 (obese).
The study revealed that atrial fibrillation recurrence after cardiac ablation dropped along with patients' BMI. Heart failure rates were greatest among those with the lowest and highest BMIs.
"We found that when it comes to atrial fibrillation, weight loss in general appears to be beneficial across all levels. However, people who become underweight despite having lower rates of atrial fibrillation have higher rates of stroke and death, similar to people who are very overweight," said Bunch.
He added that these findings show that weight loss in moderation is helpful. He also said it's important for people to become more active, and exercise daily. People with atrial fibrillation also need to take blood thinners as prescribed.
The findings were to be presented Sunday at the American Heart Association's annual meeting, in Orlando, Fla. Findings presented at meetings are generally viewed as preliminary until they've been published in a peer-reviewed journal.
The American Heart Association has more on atrial fibrillation.