Research from The University of Arizona Sarver Heart Center helps explain excessive body weight increases the risk for heart disease. Excessive body weight is associated with a thickening of the heart muscle in the left ventricle, the heart's pumping chamber. Known to physicians as left ventricular hypertrophy (LVH), the condition potentially can lead to heart failure and rhythm problems.

"We observed that the thickening in the muscle wall becomes especially noticeable in obese patients who have a Body Mass Index (BMI) of 30 or greater," says Dr. Movahed. "Previous studies have shown that left ventricular hypertrophy is associated with a higher risk of mortality."

Analyzing 17,261 heart ultrasounds, the UA researchers studied moving images of the heart to evaluate structure and function. Results showed that narrowing of the aortic valve, the main valve that carries blood away from the heart to the rest of the body, was the strongest predictor of LVH, followed by gender and Body Mass Index.

While the cause of LVH in obese patients is not known, it may be related to increased work load or to the presence of other cardiac risk factors in these patients.

"These results are another stake in the ground that supports healthy lifestyles for the benefit of heart protection," says Dr. Movahed. "Maintaining a proportionate BMI may prevent LVH and lead to better heart function."