The most common type of heart failure, HFpEF, is associated with diabetes and obesity. This influences what makes effective treatment.
By Helen Petre
Heart failure is a condition where the heartbeat is weak and where fluid builds up around the heart in the lungs, causing shortness of breath, fatigue, and swelling in the extremities. Heart failure with a preserved ejection fraction (HFpEF) is the most common type of heart failure worldwide. It is common in people who also have diabetes, obesity, and high blood pressure. Ironically, patients with HFpEF have normal heart muscle contractions, but they still have symptoms of heart failure.
What is behind HFpEF and how do we treat it?
The incidence of HFpEF is increasing globally, and so is the incidence of diabetes and obesity. Most HFpEF patients are also obese. A study done by researchers at Johns Hopkins Medicine and published in Nature Cardiovascular Research shows that the cause of HFpEF may be obesity.
Standard heart failure drugs do not work for HFpEF patients, but Johns Hopkins researchers found that the SGLT2 inhibitor (sodium glucose transporter 2 inhibitor) used to treat diabetes shows promising results as an HFpEF treatment. They also found that a weight loss drug, GLP1-receptor agonist, also improves symptoms for HFpEF patients.
What sets HFpEF apart from standard HF? The “EF” or ejection fraction is the percent of blood ejected from the left ventricle with each heartbeat divided by the volume of blood in the left ventricle when it is maximally filled. This number should be greater than 50 percent. When the heart muscle becomes stiff or thick, the volume of the heart is less, and then, even if the heart is pumping 50 percent of the volume that comes in, that just isn’t enough oxygenated blood to bring all the cells the oxygen they need.
What is the correlation between heart failure and obesity?
According to the United States Centers for Disease Control and Prevention, 41.9 percent of Americans are obese, defined as a body mass index of greater than 30. Besides being more prone to heart failure, high blood pressure, and diabetes, being obese increases the volume of blood in the body. Why? Well, if there are more cells that need oxygen and nutrients, there must be more blood vessels to get to them. The heart has to pump harder to pump more fluid to faraway places. If a fire truck is pumping water into a hose for firefighters to put out a fire, the pressure and volume is much higher if the hose is much longer. The heart works the same way.
In a hardworking heart, heart muscle thickens to be able to push more volume of blood. So even if the heart is emptying 50 percent of what is coming in, there is more volume waiting to come in and that fluid builds up around the lungs.
Lots of other bad stuff happens too, like fat tissue building up around, and even in, the heart and veins failing to move fluid against gravity up to the heart, resulting in swelling.
What does this stress do to the heart muscle cells?
The researchers developed a method to grow cells, differentiate them into cardiac cells, and look at them at the cellular level with electron microscopy. They used cells from patients with HFpEF as well as a control group. Not surprisingly, they found that the cells of most obese patients with HFpEF had nonstandard mitochondria with fat droplets. They also found that the muscle cells appeared “tattered,” unlike the control group cells, which looked healthy and had no fat droplets.
Why is this important?
While this research does not comment on the benefits of exercise and diet, it does clearly state that losing weight, however it is done, improves quality of life for obese patients with HFpEF. Heart disease, obesity, and diabetes are public health problems that are becoming more prevalent. There seems to be a logical solution to preventing “tattering” of heart muscle cells and mitochondria filled with fat. This research suggests that there are tangible solutions to obesity-related heart failure.
This study was published in the peer-reviewed journal Nature Cardiovascular Research.
The information contained in this article is for educational and informational purposes only and is not intended as health or medical advice. Always consult a physician or other qualified health provider regarding any questions you may have about a medical condition or health objectives.
References
Golla, M. S., & Shams, P. (2024). Heart failure with preserved ejection fraction (HFpEF). StatPearls Publishing. https://www.ncbi.nlm.nih.gov/books/NBK599960/
Meddeb, M., et al. (2024). Myocardial ultrastructure of human heart failure with preserved ejection fraction. Nature Cardiovascular Research, 3, 907–914. https://doi.org/10.1038/s44161-024-00516-x
United States Centers for Disease Control and Prevention. (2024, May 14). Adult Obesity Facts. https://www.cdc.gov/obesity/php/data-research/adult-obesity-facts.html
Vasan, R. S., et al. (2022). Lifetime risk of heart failure among participants in the Framingham Study. Journal of the American College of Cardiology, 79(3), 250–263. https://doi.org/10.1016/j.jacc.2021.10.043
About the Author
Helen Petre is a retired biologist who continues to learn and teach science.