Inactivity, excess weight linked to hard-to-treat heart failures

Heart failure is a chronic condition in which the heart is unable to supply enough oxygenated blood to meet the demands of the body. Heart failure is approximately equally divided between two subtypes: heart failure with preserved ejection fraction (HFpEF) and heart failure with reduced ejection fraction (HFrEF). Ejection fraction refers to the percentage of the blood that exits the heart with each contraction.

"Previous studies have consistently found an association between low levels of physical activity, high BMI, and overall risk of heart failure, but this study shows that the association is more pronounced for heart failure with preserved ejection fraction, the type of heart failure that is the most challenging to treat," said preventive cardiologist Dr. Jarett Berry, Associate Professor of Internal Medicine at UT Southwestern, and the study's senior author.

The study appears in the Journal of the American College of Cardiology.

In heart failure with preserved ejection fraction, the heart stiffens. Instead of being soft, it's rigid and it resists expansion. Cardiologists often explain the difference between the two types of heart failure by saying that in heart failure with preserved ejection fraction, the heart doesn't relax enough, while in heart failure with reduced ejection fraction the heart doesn't squeeze enough. Many treatments have been developed for treating the latter but there are no evidence-based treatments for the former.

"The five-year survival rate among heart failure with preserved ejection fraction patients is around 30 to 40 percent. While heart failure with reduced ejection fraction survival has improved significantly over the years, heart failure with preserved ejection fraction prognosis is little changed," said Dr. Ambarish Pandey, a cardiology fellow in Internal Medicine at UT Southwestern Medical Center and first author of the study.

The pooled analysis looked at data from 51,000 participants in three cohort studies, the Women's Health Initiative, the Multiethnic Study of Atherosclerosis (MESA), and the Cardiovascular Health Study. Among the 51,000 participants, there were 3,180 individuals who developed heart failure. Of these, 39 percent were heart failure with preserved ejection fraction, 29 percent were heart failure with reduced ejection fraction, and 32 percent had not been classified when the data was gathered.

The incidence of heart failure with preserved ejection fraction was 19 percent lower for individuals who exercised at recommended levels. Similarly, body mass index (BMI) had an inverse relationship with heart failure with preserved ejection fraction. Higher BMI levels were more strongly associated with heart failure with preserved ejection fraction than with heart failure with reduced ejection fraction.

Heart failure with preserved ejection fraction is a growing problem as the population ages, and is particularly a problem among elderly women.

Medications such as ACE inhibitors, beta blockers, and aldosterone antagonists have been shown in large-scale randomized trials to reduce mortality in patients with heart failure with reduced ejection fraction. Clinical trials have not identified medications that reduce mortality in patients with heart failure with preserved ejection fraction. Heart transplant is the ultimate option for some patients with heart failure with reduced ejection fraction but is not an option for patients with heart failure with preserved ejection fraction, all of which means that prevention is crucial for heart failure with preserved ejection fraction.

"These findings highlight the importance of lifestyle interventions such as increasing physical activity levels and reducing weight to combat the growing burden of this disease," said Dr. Berry, Dedman Family Scholar in Clinical Care.