Inspiratory Muscular Training

Study Overview
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Brief Summary
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Objectives: To evaluate regional lung ventilation distribution in patients suffering from chronic heart failure (CHF) after completing inspiratory muscle training (IMT) and correlate it with functional capacity and quality of life among these individuals. Methods and Results: Nineteen CHF patients were randomly assigned to two groups: Control and IMT. Before and after muscle training, subjects were submitted to assessment protocol for respiratory muscles, digital spirometry, optoelectronic plethysmography (OEP), the six-minute walk test (6MWT) and a quality of life questionnaire (MLHFQ). There was no difference in lung function following the 12-week training period in either group. However, the IMT group showed an increase in actual and predicted MIP, higher MLFHQ score and greater distance walked in the 6MWT, as well as a reduction in the Borg scale after the 6 MWT in relation to the control. For the OEP, IMT group members exhibited higher values for total chest wall volume (Vcw), abdominal rib cage volume (Vrc,a) and abdominal volume (Vab) when compared to the control. Conclusions: For patients with CHF, IMT proved efficient in improving muscle strength, functional capacity and quality of life. The present study also analyzed the distribution behavior of lung volumes for the thoracoabdominal system in this population, showing that larger abdominal rib cage and abdomen volumes may result in more effective diaphragmatic contraction.

Official Title
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REGIONAL LUNG VENTILATION DISTRIBUTION AMONG INDIVIDUALS WITH CHRONIC HEART FAILURE AFTER AN INSPIRATORY MUSCLE TRAINING PROGRAMM: A RANDOMIZED CONTROLLED CLINICAL TRIAL

Conditions
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Heart Failure

Intervention / Treatment
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* Other: Inspiratory muscle training
* Other: Control group


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: sedentary adults diagnosed with functional class II and II CHF in accordance with the New York Heart Association (NYHA); in stage B or C according to American College of Sports Medicine guidelines; with left ventricle ejection fraction lower than 45% (evaluated by echocardiogram in a period ≤ 1 year); cardiomegaly confirmed by increased left ventricle end-diastolic (LVDD) and end-systolic diameter (LVESD) associated with a cardiac index (CI) >0.5 according to chest X-rays; inspiratory muscle weakness (MIP <70% of predicted values); clinical stability with no change in medication for at least three months and sedentary (no regular physical activity performed in the previous six months or not accumulating 30 minutes or more of moderate physical activity - 3 to 6 METs - on most week days). Exclusion Criteria: patients exhibiting unstable angina, myocardial infarction or prior heart surgery up to three months before beginning the investigation; orthopedic, infectious or chronic metabolic diseases; treatment with steroids, hormones or chemotherapy; ratio between forced expiratory volume in one second and forced vital capacity (FEV1/FVC) < 70% of predicted, characterizing an obstructive respiratory disorder; respiratory diseases, smokers and ex-smokers with a history of cigarettes/day for more than 10 years.

Ages Eligible for Study
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Minimum Age: 21 Years
Maximum Age: 65 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Inspiratory Muscle Training<br>Inspiratory Muscle Training | Other: Inspiratory muscle training<br>* All participants were instructed to use a Threshold® trainer for 30min a day, seven times a week over 12 consecutive weeks.10 Patients in the Control Group used a Threshold ® device without resistance, making them blind to the treatment. For the treatment group, inspiratory resistance of the Threshold® trainer was 30% of MIP, adjusted on a weekly basis to remain constant.<br>|
| Placebo Comparator: Control group<br>Patients from the control group were also assessed weekly to ensure homogenization of the learning effect for the manometer maneuver. | Other: Control group<br>* Patients from the control group were also assessed weekly to ensure homogenization of the learning effect for the manometer maneuver.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Respiratory muscles | In order to evaluate inspiratory muscle strength, a digital manometer was used (MVD-300, Globalmed, Brazil) connected to a mouthpiece with a 2mm opening to reduce the influence of pressure caused by glottal closure. In a sitting position, each patient performed up to six maneuvers to obtain MIP, from residual volume (RV) to total functional capacity (TFC), considering the best of three maneuvers with < 10% variation between them | 3 months | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Assessment of respiratory mechanics by Optoelectronic Plethysmography | The optoelectronic plethysmography system (OEP) of BTS Bioengineering (Italy) was employed in this study. To that end, a calibration instrument was used, containing three axes connected to reflective markers. This phase does not require participation by the individual to be examined. This creates a three-dimensional model, dividing the thoracoabdominal system into three parts: pulmonary rib cage (RCp), abdominal rib cage (RCa) and the abdomen (AB). | 3 months | 
| Evaluation of submaximal functional capacity | Functional capacity was assessed by the six-minute walk test (6MWT), according to the protocol published by the American Thoracic Society (ATS). | 3 mounths | 
| Quality of Life Questionnaire: Minnesota Living With Heart Failure Questionnaire (MLHFQ) | The MLHFQ is a questionnaire validated for the Brazilian population, consisting of 21 questions regarding limitations frequently associated with the extent to which heart failure has affected patient's lives in the previous month. Each question is attributed a value from 0 (zero) to 5 (five), with the highest score indicating worse quality of life. The total score is calculated by adding the 21 items, with a possible interval between 0 and 105. | 3 months | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Heart failure, respiratory muscles, optoelectronic plethysmography