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Journal: Obesity Linked to Irregular Heartbeat

Obesity is a well-established cause of several health problems. Now a new study is the first to tie it to an irregular heartbeat, which can cause stroke and heart failure.

John Nagle, 57, no longer a slender man, went to a hospital emergency room a few years ago fearing he was about to have a heart attack, but the reason for his visit was not chest pain.

"When I first came to the hospital, there was shortness of breath, but no pain. That's when they found out that I had the irregular heartbeat," said Mr. Nagle.

Doctors call irregular heartbeat "atrial fibrillation." It is common and potentially serious, according to Harvard University Medical School physician Thomas Wang in Boston.

"Atrial fibrillation is a major cause of stroke and heart failure and may also be related to an increased risk of death. It's an abnormal rhythm of the heart that is caused when the upper chambers of the heart beat in an uncoordinated and irregular fashion," said Dr. Wang.

Prior studies have shown that advanced age, diabetes, high blood pressure, and heart disease increase the risk of atrial fibrillation. Now, Dr. Wang and colleagues have found that obesity is also a factor. The finding is based on data they extracted from ongoing research called the Framingham Heart Study.

"What we found is that obesity was associated with an approximately 50 percent increase in the risk of developing atrial fibrillation," added Dr. Want.

The researchers came to this conclusion by tracking the health of more than 5000 Framingham Heart Study participants, men and women, for about 14 years. Their average age was 57.

Dr. Wang's overweight patient, John Nagle, was not surprised to learn of the finding.

"My heart is really laboring to breathe walking up a flight of stairs or even up a slight hill, so the more weight I put on, I can tell the harder it is for the heart to work," added Mr. Nagle.

Why can obesity have an impact on heart rhythms? Again, Dr. Wang.

"We speculate that this may be the result of the effects of obesity on the structure of the heart and on the chambers of the heart where this abnormal rhythm originates," Dr. Wang noted. "Once you get atrial fibrillation, it may be very difficult for doctors to get you back into the normal rhythm. What that means for the patient is that the patient may be stuck with a lifetime of taking medications to protect against stroke and the other complications of atrial fibrillation."

The study appears in the Journal of the American Medical Association. In it, Dr. Wang and his colleagues say the prevalence of atrial fibrillation is expected to increase several-fold in the coming decades as the aging general population grows fatter. But they say that, just as obesity can be modified, so can the prospect of an irregular heartbeat.

"Interventions in the society to reduce the prevalence of obesity and overweight [people] may in fact lead to a reduction in the burden of atrial fibrillation," said Dr. Wang.