Studying Breathing in Heart Failure with Preserved Ejection Fraction (HFpEF) and Obesity

This study is looking at how breathing limitations affect shortness of breath (dyspnea on exertion or DOE) and exercise ability in people with a type of heart failure called HFpEF (Heart Failure with Preserved Ejection Fraction) and obesity. Researchers believe that obesity plays a big role in these breathing problems. You might be eligible if you are 55 to 90 years old, have signs of heart failure, and specific heart function measurements (ejection fraction > 0.50, NT-proBNP > 300 ng/dl). The study will compare breathing a special helium-oxygen gas mixture (HeO2) to normal room air to see if it improves breathing and exercise capacity. The study aims to enroll 78 participants, but its current status is unclear.

Study design
This interventional study plans to enroll 78 participants. It will compare breathing a helium-oxygen gas mixture (HeO2) to normal room air.
What's involved
You would undergo clinical screening tests, including exercise tests, lung function tests, and body composition scans. You would also breathe different gas mixtures for measurements over a few days.
Compensation
Not stated in the trial record.
Follow-up
Measurements for primary outcomes will be taken at Day 2, and Day 3 or 4.

AI-generated from the public study record. Only the study team can confirm whether you're eligible — confirm details with them before making decisions.

NCT05723679

Targeting Breathing Limitations to Improve Functional Outcomes in HFpEF

Recruiting
NAAges 55–90Interventional
University of Texas Southwestern Medical Center
~78 participants
Updated 2026-05-07 on ClinicalTrials.gov
What's tested:HeO2 gas mixtureRoom air gas mixture

At a glance

Recruiting sites
1 of 1 listed site is recruiting right now
RecruitingSuspended, closed, or not yet open
What they're measuring
O2 cost of breathing (Objective 1)
Measured over Day 2
+2 more outcomes measured
Heart Failure With Preserved Ejection Fraction
Obesity

NCT05723679

Where you'd take part

This study runs at 1 site. They're the same protocol — you choose where, and that choice sets who your contact draft is addressed to.

  • UT Southwestern Medical Center

    Dallas, Texasstudy coordinator listed

    Recruiting

Sites open and close at different times, so the status above is per site — it can differ from the study's overall status.

  • Tony G Babb, Ph.D. · PRINCIPAL_INVESTIGATOR · University of Texas Southwestern Medical Center
  • Bryce N Balmain, Ph.D. · PRINCIPAL_INVESTIGATOR · University of Texas Southwestern Medical Center

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Eligibility criteria

Inclusion

signs and symptoms of heart failure
an ejection fraction \> 0.50;
objective evidence of diastolic dysfunction. elevated biomarkers (NT-proBNP \>300 ng/dl) or HF hospitalization
healthy volunteers

Exclusion

age \< 55 years
BMI \> 50 kg/m2
Atrial fibrillation with poorly controlled heart rate
phosphodiesterase type 5 (PDE5) inhibitor use
severe valvular disease
severe Chronic obstructive pulmonary disease (COPD)
Chronic kidney disease (CKD) 4 or higher
any restriction of ambulation and mobility.
  • O2 cost of breathing (Objective 1)Day 2

    O2 cost of breathing measured during eucapnic voluntary hyperventilation, and calculated using oxygen uptake and ventilation variables.

  • Change in DOE during HeO2 breathing (Objective 2)Day 3 or 4

    Dyspnea on Exertion (DOE) will be assessed via ratings of perceived breathlessness (RPB) using a 0-10 Borg Scale, and will be compared with that measured during room air breathing.

  • Change in peak exercise capacity during HeO2 breathing (Objective 2)Day 3 or 4

    Peak exercise capacity will be assessed by measuring peak oxygen uptake (in L/min, measured via a breath-by-breath metabolic measurement system), peak power output recorded from a cycle ergometer (Watts), and/or total exercise duration (minutes).