Comparative Effects of Different Inspiratory Muscle Training Modalities in Patients With Heart Fa… (NCT07688863) | Clinical Trial Compass
By InvitationNot Applicable
Comparative Effects of Different Inspiratory Muscle Training Modalities in Patients With Heart Failure.
Chile60 participantsStarted 2026-06-17
Plain-language summary
The purpose of this study is to compare the effects of three different modalities of inspiratory muscle training (IMT) in patients diagnosed with chronic heart failure who exhibit reduced or mid-range left ventricular ejection fraction (LVEF \< 50%). Patients will be recruited from cardiac rehabilitation programs and must be clinically stable before entering the protocol.
The study has a total duration of 8 weeks and is divided into two distinct phases. During the first 2 weeks, participants will undergo a familiarization phase to learn the proper breathing techniques with the devices and to complete baseline resting and functional clinical evaluations. The following 6 weeks will comprise the effective training phase, consisting of 3 weekly sessions of high-intensity inspiratory training.
Participants will be randomly assigned to one of three parallel groups:
* Group 1 (Pressure-Threshold IMT): Participants will train using a mechanical pressure-threshold device at an initial high-intensity load of 60% of their baseline maximal inspiratory pressure (MIP).
* Group 2 (Electronic Flow-Resistive IMT): Participants will train at a high-intensity load of 60% of their baseline MIP utilizing the PowerBreathe KH2 electronic device, which provides a dynamic, flow-dependent automated resistance.
* Group 3 (Control / Sham IMT): Participants will perform the same breathing protocol but using a mechanical device set at a low, non-training intensity of 15% of their baseline MIP.
For all three groups, training volume is standardized to 5 sets of 8 repetitions (40 inspiratory efforts per session). To ensure progressive overload, training intensity will be increased by 10% of the initial baseline MIP value every 2 weeks.
The main outcomes to be evaluated before and immediately after the 8-week period include maximal inspiratory muscle strength, structural changes in respiratory muscles (diaphragmatic and parasternal intercostal thickening fraction measured via ultrasound), cardiac autonomic balance (heart rate variability), and health-related quality of life. Additionally, dynamic responses such as respiratory and locomotor muscle oxygenation (measured continuously via Near-Infrared Spectroscopy \[NIRS\] during a respiratory metabolic reflex provocation test) and overall cardiopulmonary exercise capacity (measured via an incremental cycle ergometer test) will be analyzed.
This study aims to determine which training modality provides the most effective physiological adaptations to optimize rehabilitation in this population.
Who can participate
Age range
18 Years
Sex
ALL
See this in plain English?
AI-rewrites the medical criteria so a patient or caregiver can understand them. Always confirm with the trial site.
Inclusion criteria
. Documented clinical diagnosis of chronic Heart Failure with Reduced Ejection Fraction (HFrEF) according to the European Society of Cardiology (ESC) guidelines.
. Left Ventricular Ejection Fraction (LVEF) less than or equal to 40% documented by echocardiography within the last 12 months.
. Clinically stable condition for at least 3 months prior to enrollment, with no hospitalizations or major changes in optimized medical therapy.
. New York Heart Association (NYHA) functional class I to IV.
. Evidence of inspiratory muscle weakness, defined as a baseline Maximal Inspiratory Pressure (MIP) \< 70% of the predicted value for age and sex.
. Age greater than or equal to 18 years.
Questions worth asking your doctor
Bring these to your next appointment. They're a starting point for a shared conversation — not a sign you qualify or a recommendation to enrol.
1Based on my diagnosis and history, is this trial worth exploring for me — or is there a standard treatment we should try first?
2What does this trial's phase tell us about how much is already known about its safety and benefit?
3What would taking part actually involve for me — visits, tests, time, and travel?
4What are the known and possible risks or side effects I should weigh, and how would they be monitored?
5If this trial isn't the right fit, what other options or trials would you suggest I look into?
Generated to help you prepare — always confirm anything about your own eligibility and care with the study team and your doctor.
Questions for the trial coordinator
The trial coordinator is the person who runs the study day to day. These cover the practical side — logistics, costs, and what taking part would actually mean for your life. The study team confirms whether you meet the criteria; these are questions to ask, not a sign you qualify.
1What does taking part actually involve week to week — how many visits, where, and how long does each one take?
2What costs are covered by the study, and what might I have to pay for myself, including travel, parking, or time off work?
3What happens during screening, and what happens if the study team confirms I don't meet the criteria after those tests?
4Who pays for the scans, blood work, and other tests the trial requires — the study, my insurance, or me?
5How will being in the trial affect my regular care, and will my own doctor stay informed and involved?
6Can I leave the trial at any point if I change my mind, and what would happen to my care if I do?
A starting point for the conversation — always confirm anything about your own eligibility, costs, and care with the study team and your doctor.
What they're measuring
1
Change in Maximal Inspiratory Pressure (MIP)
Timeframe: Baseline (Week 0) and post-intervention (Week 9).
2
Change in Peak Oxygen Consumption (VO2 peak)
Timeframe: Baseline (Week 0) and post-intervention (Week 9).
3
Change in Health-Related Quality of Life via Minnesota Living with Heart Failure Questionnaire (MLHFQ)
Timeframe: Baseline (Week 0) and post-intervention (Week 9).
. Patient must be capable of understanding the protocol instructions and must provide signed written informed consent.
Exclusion criteria
. Presence of primary severe pulmonary or respiratory diseases (e.g., Chronic Obstructive Pulmonary Disease \[COPD\] GOLD stage III or IV, active asthma, severe pulmonary hypertension, or restrictive lung disease).
. Recent myocardial infarction, unstable angina, or coronary artery bypass graft (CABG) surgery within the last 6 months.
. Severe uncorrected valvular heart disease or complex, uncontrolled ventricular arrhythmias.
. Orthopedic, neurological, or musculoskeletal limitations that prevent the safe execution of an incremental cardiopulmonary exercise test on a cycle ergometer or the performance of the isometric handgrip protocol.
. Cognitive impairment or psychological conditions that limit the ability to follow instructions, maintain correct diaphragmatic breathing technique, or properly seal the training device mouthpiece.
. Current participation in another structured physical rehabilitation or formal sports training program that could confound the systemic results of the intervention.
. Any acute infectious, inflammatory, or medical condition that, in the investigator's opinion, poses a safety risk during high-intensity training.