The Effect of Inspiratory Muscle Training on Breathing Pattern and Functionality in Patients With Chronic Heart Failure.

The study protocol aims to examine the impact of inspiratory muscle training on dysfunctional breathing and functional ability in patients with chronic heart failure. Inspiratory muscle training is a low-cost intervention that might improve the breathing pattern, functionality and overall quality of life in patients with chronic heart failure

• Inspiratory muscle training (Device): Participants will perform 20 sessions of respiratory muscle strengthening (20 minutes at 30-60% of MIP), using the Threshold Inspiratory Muscle Training device

Primary outcomes

• Diaphragmatic Thickness [From enrollment to the end of treatment at 4 weeks]: Diaphragmatic thickness measured by ultrasound is a non-invasive, widely used method to assess diaphragm structure in patients with chronic heart failure. Thickness is measured between the pleural and peritoneal lines at end-expiration and end-inspiration
• Dysfunctional breathing [From enrollment to the end of treatment at 4 weeks]: Dysfunctional breathing refers to abnormal breathing patterns that are often related to the heart's inability to supply blood effectively, affecting respiratory function. Dysfunctional breathing will be assessed with the Hi-Lo breathing test, an observational clinical test used to assess breathing pattern and diaphragm function. The clinician observes and palpates whether the movement is greater under the upper chest hand (Hi) or lower abdomen hand (Lo).The test is scored as "Yes" if upper chest (apical) breathing predominates and "No" if normal diaphragmatic breathing is present.
• Functional ability [From enrollment to the end of treatment at 4 weeks]: Functional ability refers to how well patients can perform daily activities and maintain independence despite their cardiac condition. It will be assessed with the 6-Minute Walk Test (6MWT), a simple and effective tool that evaluates the maximum distance a person can walk in six minutes. The outcome reflects the integrated response of the cardiovascular system mainly, and exercise tolerance.

Secondary outcomes

• Maximal inspiratory pressure [From enrollment to the end of treatment at 4 weeks]: It is a measure of the strength of inspiratory muscles, primarily the diaphragm. MIP is a reliable and reproducible measure that does not depend on the patient's respiratory flow.
• Functional Dyspnea [From enrollment to the end of treatment at 4 weeks]: Functional dyspnea will be measured with the Medical Research Council (MRC) Dyspnea scale, a simple grading system to evaluate the functional disability due to dyspnea. The scale ranges from 1 to 5, where 1 indicates breathlessness only with strenuous exercise and 5 indicates breathlessness that prevents leaving the house or occurs when dressing or undressing. Higher scores represent worse functional status (more severe dyspnea).
• Health Related Quality of life [From enrollment to the end of treatment at 4 weeks]: Quality of life will be evaluated with the Short Form Survey, a questionnaire with 12-items, that measures quality of life in terms of physical and mental health. It generates scores typically ranging from 0 to 100, with higher scores indicating better health status and quality of life.

Sex: All, ages: 18 Years to any

Inclusion Criteria:

* adults aged ≥ 18 years
* diagnosis of heart failure within the previous three to twelve months
* current outpatients in a stable optimal medical regimen for at least 3 months
* able to perform inspiratory muscle training
* clinically stable, without hospital admission in the previous 3 months and without participation in any other training program in the previous 6 months

Exclusion Criteria

* unstable angina
* recent acute myocardial infarction
* uncontrolled hypertension
* valve disease
* peripheral arterial disease
* 6MWT assessment of less than 300 meters
* previous pulmonary disease (forced vital capacity <80% of predicted and/or forced expiratory volume in 1 s <70% of predicted)
* history of exercise-induced asthma
* smokers

• Irini Grammatopoulou, Phd, Post Doc, Study director, University of West Attica, Athens, Greece