Yôga and Breathing Techniques Training in Patients With Heart Failure and Preserved Ejection Fraction

Yôga and Breathing Techniques Training in Patients With Heart Failure and Preserved Ejection Fraction: Study Protocol for a Randomized Clinical Trial

Current therapies for heart failure (HF) bring together strategies to improve quality of life and exercise tolerance, as well as to reduce morbidity and mortality. Some HF patients present changes in the musculoskeletal system and inspiratory muscle weakness, which may be restored by inspiratory muscle training, thus increasing respiratory muscle strength and endurance, maximum oxygen consumption (VO2), functional capacity, respiratory responses to exercise, and quality of life. Yoga therapies have been shown to improve quality of life, inflammatory markers, and VO2 peak in HF patients, mostly with reduced ejection fraction (HFrEF). However, the effect of different yoga breathing techniques in patients with HF with preserved ejection fraction (HFpEF) has yet to be assessed.

Yôga techniques without breathing control have shown to improve oxygen consumption in patients with HF, mostly HFrEF. However, almost half of HF patients present with HFpEF, and less studies have been performed in those patients. It has been recently demonstrated that HFpEF induces significant molecular, mitochondrial, histological, and functional alterations in the diaphragm and soleus, which were attenuated by exercise training . In cardiac disease and aging, several authors have shown a significant reduction in heart rate variability (HRV) in the frequency ranges associated with breathing, by using spectral analysis of heart rate (HR) and respiration.Therefore, the present randomized clinical trial (RCT) will be conducted in order to test the hypothesis that an program of yôga and specific breathing techniques with different ventilatory rhythms could be associated with improvement in inspiratory muscle responses, functional capacity, oxygen uptake efficiency slope (OUES), circulatory power, oscillatory ventilation, kinetics of oxygen consumption in the recovery period, distinct features of the autonomic nervous system, natriuretic peptides, echocardiographic measurements, and quality of life (QoL) in patients with HFpEF, with and without inspiratory muscle weakness (IMW).Therefore, the present randomized clinical trial (RCT) will be conducted in order to test the hypothesis that an 8-week program of yôga and specific breathing techniques with different ventilatory rhythms could be associated with improvement in inspiratory muscle responses, functional capacity, oxygen uptake efficiency slope (OUES), circulatory power, oscillatory ventilation, kinetics of oxygen consumption in the recovery period, distinct features of the autonomic nervous system, natriuretic peptides, echocardiographic measurements, and quality of life in patients with HFpEF, with and without IMW.

Inclusion Criteria:

• Adult patients with a diagnosis of HFpEF, functional capacity class II and III, who are being treated at a specialized HF clinic will be eligible. HF diagnosis will be established by clinical history (signs and symptoms), echocardiographic findings (left ventricular ejection fraction ≥ 50%) and medical records confirming management for HF.

Exclusion Criteria:

• Pulmonary disease (forced vital capacity<80% of predicted and/or forced expiratory volume in 1 s <70% of predicted, significant mitral or aortic valve diseases, history of exercise-induced asthma, and active smoking or alcoholic.