Improving exercise endurance in heart failure patients

Matching Perfusion and Metabolic Activity in HFpEF

Phase 2 Interventional University of Pennsylvania · NCT04913805

This study is testing if Potassium Nitrate, with or without extra supplements, can help people with heart failure improve their exercise endurance and muscle function.

Quick facts

PhasePhase 2
Study typeInterventional
Enrollment53 (estimated)
Ages18 Years and up
SexAll
SponsorUniversity of Pennsylvania Academic / other
Locations1 site (Philadelphia, Pennsylvania)
Trial IDNCT04913805 on ClinicalTrials.gov

What this trial studies

This study tests the effects of Potassium Nitrate (KNO3), with and without additional supplements Propionyl-L-Carnitine (PLC) and Nicotinamide Riboside (NR), on exercise endurance and muscle function in patients with Heart Failure with Preserved Ejection Fraction (HFpEF). Participants will undergo a standardized MRI assessment to evaluate skeletal muscle oxidative capacity and determine who may benefit most from the treatments. The study aims to enhance submaximal exercise endurance and improve skeletal muscle oxidative phosphorylation capacity in this patient population.

Who should consider this trial

Good fit: Ideal candidates include individuals with NYHA Class II-III symptoms and a left ventricular ejection fraction of 50% or greater.

Not a fit: Patients with severe heart failure symptoms or those not meeting the inclusion criteria may not benefit from this study.

Why it matters

Potential benefit: If successful, this study could lead to improved exercise capacity and quality of life for patients with HFpEF.

How similar studies have performed: Other studies have explored similar pharmacologic approaches, but this specific combination and methodology is relatively novel.

Eligibility criteria

Show full inclusion / exclusion criteria
Inclusion Criteria:

1. NYHA Class II-III symptoms
2. Left ventricular ejection fraction \>= 50%
3. Stable medical condition for at least 2 weeks, as per investigator judgment
4. Prior or current evidence for elevated filling pressures as follows:

   a. Mitral early (E)/mitral septal tissue annular (e') velocity ratio \> 8, in the context of a septal e' velocity \<=7, in addition to one of the following: i. Large left atrium (LA volume index \> 34 mL/m2) ii. Chronic loop diuretic use for control of symptoms iii. Elevated natriuretic peptides within the past year (e.g. NTproBNP \> 125 pg/mL in sinus rhythm or \> 375 pg/mL if in atrial fibrillation) b. Mitral E/e' ratio \> 14 at rest or during exercise c. Elevated invasively-determined filling pressures previously (resting left ventricular end-diastolic pressure \>= 16 mm Hg or pulmonary capillary wedge pressure \>= 15 mmHg; or PCWP/LVEDP \>= 25 mmHg with exercise) d. Prior episode of acute heart failure requiring IV diuretics

Exclusion Criteria:

1. Age \<18 years old
2. Pregnancy:
3. Treatment with organic nitrates or phosphodiesterase inhibitors that cannot be interrupted
4. Uncontrolled atrial fibrillation, as defined by a resting heart rate \> 100 beats per minute at the time of the baseline assessment
5. Hemoglobin \< 10 g/dL
6. Subject inability/unwillingness to exercise
7. Moderate or greater left sided valvular disease (mitral regurgitation, aortic stenosis, aortic regurgitation), mild or greater mitral stenosis, severe right-sided valvular disease
8. Known hypertrophic, infiltrative, or inflammatory cardiomyopathy
9. Clinically significant pericardial disease, as per investigator judgment
10. Current angina due to clinically significant epicardial coronary disease, as per investigator judgment
11. Acute coronary syndrome or coronary intervention within the past 2 months
12. Primary pulmonary artery hypertension (WHO Group 1 Pulmonary Arterial Hypertension)
13. Clinically significant lung disease as defined by: Chronic Obstructive Pulmonary Disease meeting Stage III or greater GOLD criteria (FEV1\<50%), treatment with oral steroids within the past 6 months for an exacerbation of obstructive lung disease, current use of supplemental oxygen aside from nocturnal oxygen for the treatment of obstructive sleep apnea, desaturation to \<90% on the baseline maximal effort cardiopulmonary exercise test
14. Clinically-significant ischemia, as per investigator's judgement, on stress testing without either (1) subsequent revascularization, (2) an angiogram demonstrating the absence of clinically significant epicardial coronary artery disease, as per investigator judgment; (3) a follow-up 'negative' stress test, particularly when using a more specific technique (i.e., a negative perfusion imaging test following a 'positive' ECG stress test)
15. Left ventricular ejection fraction \< 45% on a prior echocardiogram or cardiac MRI, unless the reduced LVEF occurred within the context of an uncontrolled supraventricular arrhythmia, with return of a normal ejection fraction following treatment of the arrhythmia
16. Significant liver disease impacting synthetic function or volume control (ALT/AST \> 3x ULN, Albumin \< 3.0 g/dL)
17. eGFR \< 30 mL/min/1.73m\^2
18. Methemoglobin \> 5%
19. Serum potassium \> 5.0 mEq/L
20. Severe right ventricular dysfunction
21. Baseline resting seated systolic blood pressure \> 180 mmHg or \< 100 mmHg
22. Persistently low (\<100 mmHg) or high (\>180 mmHg) seated blood pressure at the baseline visit
23. Orthostatic blood pressure response to the transition from supine to standing (\>20 mmHg reduction in systolic blood pressure 2-3 minutes after standing)
24. Active participation in another study that utilizes an investigational agent (observational studies/registries allowed)
25. Any condition that, in the opinion of the investigator, will interfere with the performance and completion of the study.

Where this trial is running

Philadelphia, Pennsylvania

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.
Conditions Heart Failure With Preserved Ejection Fraction
Last reviewed 2026-06-15 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.