New Delhi, Aug 2 (IANS): US researchers have found how obesity impacts muscle structure in patients with a form of heart failure called "heart failure with a preserved ejection fraction (HFpEF)".

HFpEF is responsible for more than half of all heart failure worldwide. It also has quite high hospitalisation and death rates (30-40 per cent over 5 years).

While it used to be generally associated with having high blood pressure and excess muscle growth (hypertrophy), in the last 20 years, HFpEF has been occurring more often in patients with severe obesity and diabetes.

Even as both obesity and diabetes are rising globally, understanding the underlying causes of the diseases is critical, said researchers from Johns Hopkins University.

For the study, published in the journal Nature Cardiovascular Research, the team obtained a small piece of muscle tissue from 25 patients who had been diagnosed with varying degrees of HFpEF caused by diabetes and obesity. They compared them to heart tissue from 14 organ donors whose hearts were considered to be normal.

Obese patients with HEpEF had notable ultrastructural abnormalities. Their mitochondria were swollen, pale, and disrupted, had many fat droplets, and their sarcomeres appeared tattered.

These were not related to whether the patient had diabetes, and were less prominent in patients who were less obese, revealed the results.

David Kass, Professor of Medicine at the varsity’s School of Medicine said the finding raises a pertinent question "of whether reducing obesity, as is now being done with several drug therapies, will reverse these ultrastructural abnormalities, and in turn improve HFpEF outcome".