RecruitingNot ApplicableNCT05582044

Exercise Lower-body Negative Pressure in Heart Failure With Preserved Ejection Fraction

The Effect of Lower-body Negative Pressure on Exercise Tolerance and Mechanisms of Dyspnea in Heart Failure With Preserved Ejection Fraction

Sponsor

University of British Columbia

Enrollment

60 participants

Start Date

Jan 25, 2023

Study Type

INTERVENTIONAL

Conditions

Heart Failure With Preserved Ejection Fraction

Summary

The heart is a pump that must both fill and empty effectively to move blood; if it cannot move enough, heart failure may ensue. Approximately half of all adults living with heart failure have a form where the heart stiffens, which impairs its ability to fill. This form of heart failure particularly affects females and older adults. When people exercise, extra blood returns to the heart. The healthy heart can easily fill and move this extra blood to the muscles. However, when the heart's ability to fill is impaired, the extra blood can back up and pool in the lungs. Blood pooling in the lungs makes people feel breathless, although the investigators do not fully understand why, and this form of heart failure has a high risk of hospitalization and death, but few effective treatments are available. Exercise is one of the few treatments that works well if enough exercise is performed regularly. However, many people with this form of heart failure can only tolerate a small amount before stopping due to severe breathlessness, which can put them off from exercising regularly. The study's goal is to help these people perform more exercise. The investigators will use a novel form of stationary cycling with a plastic chamber around the lower body that seals at the waist. The chamber can apply suction to the lower body during exercise which will reduce how much extra blood returns and prevent the heart and lungs from being overloaded. Participants will attend 5 visits, including 3 where they will perform a submaximal exercise test for as many minutes as possible with or without light suction. In each of these tests, the investigators will record how long they exercise and ask them to rate how breathless they feel. The investigators will also study their breathing pattern, using a mouthpiece and pressure sensor, and heart function, using ultrasound imaging. This work will help adults living with heart failure exercise more and improve their health, and help researchers understand what causes breathlessness and develop new treatments.

Eligibility

Min Age: 40 Years

Inclusion Criteria14

Adults with a clinical diagnosis of HFpEF (LV ejection fraction ≥50%) measured in the year prior to Visit 1 (and confirmed at Visit 1), who are New York Heart Association Functional Class II-III (mild-moderate symptoms), ambulatory, receiving guideline-directed medical therapy unchanged for ≥2 months, and clinically stable for ≥3 months.
Symptom(s) of heart failure requiring treatment within the year prior to Visit 1
NT-proBNP \>50 pmol/L (sinus rhythm) or \>150 pmol/L (atrial fibrillation in year prior)
Diastolic dysfunction based on at least one of the following echocardiographic findings:
Left atrial enlargement (diameter \>4 cm or volume index \>28 mL/m2); or
e' \<10 cm/s (lateral) or \<8 cm/s (septal), or
E/e' \>10 (lateral), or \>15 (septal)
\- Healthy sedentary or recreationally active adults from the community
Seated blood pressure ≥140/90 mmHg
Any other chronic systemic illness
Current or recent (within the past 6 months) smoking
Body mass index \>35 kg/m2
Contraindication to exercise or otherwise unable to perform cycle ergometry
Poor echocardiographic imaging windows

Exclusion Criteria20

Any prior measurement demonstrated LV ejection fraction ≤40%
Primary pulmonary, metabolic, renal, hepatic, neuromuscular, or malignant disease
Primary pulmonary vascular, complex congenital, or \> mild valvular heart disease
Documented infiltrative cardiomyopathy
Documented valvular or coronary disease requiring intervention
Myocarditis, pericardial effusion, acute coronary syndrome, or revascularization in the last 3 months
Resting seated systolic blood pressure \>160 mmHg or \<100 mmHg
Jugular venous pressure \>12 cm
Inferior vena cava \>2 cm with no inspiratory collapse, or severe right ventricular dysfunction by echo
Ambulatory supplemental oxygen
Current or recent participation in \>150 min. per week of moderate intensity exercise
Current or recent (within the past 6 months) smoking
Body mass index \>35 kg/m2
Contraindication to exercise or otherwise unable to perform cycle ergometry
Poor echocardiographic imaging windows
Current or recent participation in \>150 min. per week of moderate intensity exercise
History of any cardiovascular condition or cardioactive drug use
History of any respiratory condition including asthma
History of any metabolic condition including diabetes
Non-sinus rhythm

Interventions

OTHERLower-body Negative Pressure (-25 mmHg)

The LBNP chamber will be sealed at the waist prior to Control measures, and the vacuum system will be activated to coincide with the onset of exercise, applying -25mmHg LBNP.

OTHERLower-body Negative Pressure (-15 mmHg)

The LBNP chamber will be sealed at the waist prior to Control measures, and the vacuum system will be activated to coincide with the onset of exercise, applying -15mmHg LBNP.

OTHERLower-body Neutral Pressure (0 mmHg)

In this placebo trial, the LBNP chamber will be sealed at the waist prior to Control measures, and the vacuum system will be activated to coincide with the onset of exercise, but the chamber will be vented to atmosphere.