The administration of potassium nitrate (KNO3) does not improve exercise capacity or quality of life in patients with heart failure with preserved ejection fraction (HFpEF), despite increasing levels of nitric oxide in blood.

"In this randomized crossover trial, chronic KNO3 [potassium nitrate] administration did not improve exercise capacity or quality of life, as compared with KCl [potassium chloride] among participants with HFpEF," the authors of the study wrote.

The study was led by Payman Zamani, MD, MTR, of the Perelman School of Medicine at the University of Pennsylvania, in Philadelphia. It was published online on December 18, 2024, in JAMA Cardiology.

The potential activation of compensatory mechanisms by the chronic inorganic nitrate administration may have neutralized the short-term benefits. Various abnormalities in oxygen transport may be present simultaneously in patients with HFpEF, suggesting a combination of interventions may be required to improve exercise capacity.

This trial was supported by the National Heart, Lung, and Blood Institute. The study was supported by the National Center for Advancing Translational Sciences and National Institutes of Health. Some authors reported receiving grants, personal fees, and consulting fees and having patents from various pharmaceutical and medical device companies and institutes. One author reported having full-time employment with a healthcare company.