Inspiratory Muscle Training for Dyspneic Patients With COPD-HF Overlap: a Multicenter, Randomized Controlled Trial

Chronic obstructive pulmonary disease (COPD) and heart failure with reduced left ventricular ejection fraction (HF) are leading causes of disability and death worldwide. Unfortunately, COPD and HF coexist in up to a third of elderly patients making the so-called COPD-HF overlap (CHO) a major challenge to Health Care Systems. In addition, population ageing anticipates that CHO prevalence will further increase in the next decades.

Intolerance to exertion due to disabling breathlessness is the hallmark of COPD and HF and these abnormalities are notoriously potentiated by diseases coexistence.

The inspiratory muscles are centrally related to the pathophysiology of exertional dyspnea in COPD and HF. In both populations a higher central motor command output is required to maintain adequate force generation in the face of weaker inspiratory muscles. This information is interpreted as "shortness of breath".

There is well established evidence gained from recent meta-analyses indicating that inspiratory muscle training (IMT), as a standalone therapy, significantly improves inspiratory muscle function (strength and endurance), dyspnea during daily activities, and functional exercise capacity in COPD and HF. Previous findings indicate that reduced pressure-generating capacity reflecting inspiratory muscle weakness is frequently observed in patients with COPD-HF and related to a clinically-relevant outcome: exertional dyspnea. These findings set the scene for a randomized controlled trial to investigate the potential role of IMT in dyspnea palliation in CHO patients.

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