Integrative respiratory and skeletal musculature training in patients with functional class II-IV chronic heart failure and low or intermediate left ventricular ejection fraction: design and rationale

Respiratory system remodeling plays an important role in the progression of congestive heart failure (CHF). Decreased oxygenation of the respiratory muscles during intense physical exertion in patients with CHF may aggravate respiratory failure and provoke hyperactivation of the inspiratory metaborefl ex, thereby aggravating exercise intolerance due to a decrease in muscular system perfusion. Respiratory muscle training can minimize the eff ects of inspiration metaborefl ex activation and prolong the duration of exercise.Trial design. This is a prospective randomized trial with a sham control. The trial will include 40 adult patients of both genders with NYHA II-III CHF and with ejection fraction (EF) ≤ 49%. Patients will be randomized in a 1:1 ratio to either Active or Control group. Active group will receive four-week guided respiratory muscles training followed by 12-week guided aerobic training (treadmill walking). Control group will receive four-week sham respiratory muscles training (THRESHOLD® IMT breathing trainer with level slightly above 0), followed by 12 weeks guided aerobic training (treadmill walking). The primary aim is to compare the eff ect of diff erent training modalities on functional capacity (peak VO2 ). Secondary outcome measures include changes in respiratory muscle strength, serum biomarkers (NT-proBNP and ST2) and Angiotensin II. Health-related quality of life (MLwHFQ.23) and psycho-emotional state of patients also will be assessed.The study also planned an additional analysis with a suitable group of patients who were screened but refused to participate in the study.Conclusion. Heart failure patients often give up exercise due to symptoms of shortness of breath and muscle weakness. We suggest that the training technique based on the inclusion of respiratory muscle training as the fi rst stage of cardiac rehabilitation will positively aff ect the eff ectiveness of subsequent aerobic training in patients with heart failure, by reducing the activity of RAAS and SAS and increasing respiratory effi ciency.