In a nutshell
This study investigated what changes obesity causes to the heart tissue that may explain why obesity leads to heart problems such as impaired blood flow in the heart and heart failure.
Some background
Obesity is a disorder where a person is significantly overweight due to an excessive amount of body fat. Obesity causes a number of health problems including increasing the risk of developing heart disease, high blood pressure and heart failure.
The heart is composed of four chambers: two atria that pump and receive blood from the lungs, and two ventricles that pump and receive blood from the rest of the body. When the heart relaxes (diastole), the ventricles fill with blood.
Obesity is associated with diastolic dysfunction and lower heart blood flow. Diastolic dysfunction is when the heart fails to relax normally and blood cannot fill into the ventricles properly. This causes a build up of pressure inside of the ventricles as blood from the next heart beat tries to enter. This can result in high blood pressure and a build up of blood leading to shortness of breath and increasing the risk of heart failure.
It is known that obesity causes diastolic dysfunction and increased heart pressure but it is not known how or why it occurs.
Methods & findings
This study examined heart tissue from obese and non-obese individuals to see if it could provide clues as to how obesity causes diastolic dysfunction and impaired heart blood flow. The study included 57 patients who were already undergoing heart surgery. A heart biopsy was carried out after the surgery, which is where a piece of heart tissue is taken and examined under a microscope.
The study found that obese patients had narrowed small blood vessels (capillaries) in the heart in comparison with non-obese patients.
The bottom line
The study concluded that obesity causes small blood vessels in the heart to become narrowed. This in turn may reduce the heart’s ability to relax and fill with blood properly, subsequently resulting in diastolic dysfunction, impaired blood flow, and a higher risk of heart failure in obese individuals.
The fine print
The study was conducted on a small group of patients and therefore the results of this study may not be true for an entire population.
What’s next?
If you or someone you know are obese, talk to a doctor or dietician about ways you can improve your weight and health in order to reduce the risk of heart failure.
Published By :
PLOS ONE
Date :
Nov 29, 2013
