Heart Failure Worsens Muscle Strength in COPD

Heart Failure Worsens Leg Muscle Strength and Endurance in Patients With Chronic Obstructive Pulmonary Disease

The combination of heart failure (HF) and chronic obstructive pulmonary disease (COPD) is highly prevalent, but underdiagnosed and poorly recognized. It has been suggested that the decline in functional capacity is associated with musculoskeletal and systemic changes than primary organ (heart and/or lung) failure. In addition, it is recognized that both diseases have several mechanisms that are responsible for musculoskeletal impairment. However, the association of reduced systemic perfusion with low oxygen content observed in the association of HF and COPD may contribute to the worsening of the components of the muscle impairment cascade. Thus, muscle strength and fatigue may not only be even more altered but may also be the main determinants of functional capacity in patients with coexistence of HF and COPD. Although many studies have evaluated the muscle performance of patients with HF or COPD, the literature did not show data on worsening due to the association of the diseases. Particularities identification of the muscle impairment in the coexistence of HF and COPD is fundamental for the development of rehabilitation strategies, mainly through physical exercise. In this line, the present study tested the hypothesis that the coexistence of HF and COPD could present lower values of strength and greater fatigue. Similarly, the muscle dysfunction degree could strongly correlate with the performance markers of the incremental or functional tests in patients with HF associated with COPD.

The study protocol was reviewed and approved by the Institutional Research Board. All subjects gave written informed consent before participating in the study.

Inclusion Criteria:

• non-cachectic sedentary patients
• moderate-to-severe COPD according to GOLD classification (FEV1/ FVC <0.7 and predicted post-bronchodilator FEV1 between 30% and 80%)
• no clinical or echocardiographic evidence of HF for the COPD group
• echocardiographic evidence of HF with reduced left ventricular ejection fraction (<40%) for the overlap group
• chronic dyspnoea (MRC scale score 2-4)
• NYHA class 2 or 3.

Exclusion Criteria:

• long-term O2 therapy
• recent (within a year) rehabilitation program
• osteomuscular limitation
• type I or non-controlled type II diabetes mellitus
• peripheral arterial disease associated with claudication
• Patients with preserved ejection fraction HF