Size Matters -- Obesity Leading Risk Factor for
Reported November 12, 2009
(Ivanhoe Newswire) -- Aside from aging itself, obesity appears to be
the most powerful predictor of left atrial enlargement (LAE), significantly
increasing one's risk of atrial fibrillation, stroke and death.
Researchers in Lubeck, Germany, found obesity and hypertension to be
independent predictors of LAE, both resulting in a variety of structural and
functional changes in the heart. The highest measures of left atrial volume
(iLA) were seen in obese patients with high blood pressure. This group also
had the greatest increase in iLA and the highest incidence of LAE upon
follow-up. The effect of obesity was almost twice that of hypertension.
In individuals with high blood pressure, the heart has to deal with greater
pressure, which results in a thickening of the walls of the left ventricle.
This change also affects the left atrium as the pressure in this chamber
ultimately increases as well as resulting in enlargement and loss of
function of the atrium.
The mechanisms by which obesity might promote the increased size of the left
atrium are seemingly more complex. Obese subjects may undergo dilatation of
this chamber because of the cardiac output. The heart of an obese person
must transport more blood per minute, which may lead to a volume overload in
the left atrium.
In the context of the growing obesity epidemic, authors stress the
importance of early assessment and intervention, especially in younger obese
patients, to prevent the premature onset of cardiac remodelingóchanges in
size, shape, and function of the heartóresulting from LAE. Authors caution
that the extent to which weight management or moderate weight loss can
improve LAE remains unclear and needs further investigation.
SOURCE: Journal of the American College of Cardiology, November 17, 2009