Obesity Raises Risk of Left Atrial Enlargement, a Risk Factor for Atrial Fibrillation (AF)

December 08, 2009 6:13 AM CT

By Peggy Noonan

New research published in the November 17, 2009 issue of the Journal of the American College of Cardiology shows obesity and high blood pressure (hypertension) to be significant risk factors for left atrial enlargement (LAE), a condition in which the left upper chamber of the heart is oversized. LAE is an independent risk factor for afib, stroke and death.

The researchers reviewed data collected over 10 years from 1,212 men and women aged 25 to 74 who lived in the Augsburg area of Germany and who had echocardiograms to measure left arterial volume (size) at the start of the study and again after 10 years.

Their analysis found both obesity and high blood pressure to be “significant” and “independent predictors of LAE,” Dr. Jan Stritzke and coauthors report. “Both obesity and hypertension were found to be independent risk factors for LAE” but “obesity is the main risk factor.”

The authors indicated that while more cases of atrial fibrillation today are related to hypertension than to other cardiovascular risk factors, obesity may overtake hypertension as the main atrial fibrillation risk factor.

The new study confirmed previous research showing that body mass index (BMI), a measure of body fat based on height and weight, is an independent predictor of LAE. “We found strong associations of obesity, arterial hypertension, and age with LA (left atrial) size,” they report.

Obesity alone also was linked to the degree of left atrial size and people who were obese and also had high blood pressure had the greatest enlargement.

Comments: From this research, we know that keeping blood pressure and weight under control is a good idea to decrease atrial fibrillation risk. We also know that atrial remodeling, which enlarges the left atrium, happens once you have afib. So one interesting question to ask in the wake of this research is whether losing weight and keeping blood pressure under control once you have afib can decrease the amount of left atrial enlargement that you experience from afib, or is it unrelated. Hopefully more research will provide us an answer.

To read more about the study, see:

To calculate your body mass index (BMI):

Peggy Noonan specializes in writing about health for consumers and medical professionals. She writes for leading national magazines and consumer publications as well as StopAfib.org.