Arq. Bras. Cardiol. 2022; 118(4): 692-693
Lung Function and Inspiratory Muscle Strength in Heart Failure: Can They be Considered Potential Prognostic Markers?
This Short Editorial is referred by the Research article "Relationship of Lung Function and Inspiratory Strength with Exercise Capacity and Prognosis in Heart Failure".
Heart failure (HF) is a complex syndrome considered a major public health problem. Different HF subtypes are classically defined based on left ventricular ejection fraction (LVEF). Although its prognosis has improved in recent decades – explained, in part, by major therapeutic advances – HF persists with a high burden of mortality and negatively influences the quality of life., In this sense, common symptoms experienced in this disease, such as shortness of breath and exercise intolerance, contribute greatly to this sharp decline in the quality of life of individuals. Another condition, considered an important risk factor, which usually accompanies HF, is pulmonary dysfunction. The respiratory impairments observed in HF may be related to several reasons, such as an impairment of lung mechanics and gas diffusion, as well as respiratory muscle weakness – aggravating increased dyspnea, being a major limitation on physical exercise.
Spirometry is a widely used test that allows the analysis of lung function – by measuring the amount of air inhaled and exhaled to the maximum. Because chronic obstructive pulmonary disease shares similar signs and symptoms with HF, its identification in individuals with HF can be challenging; in this sense, spirometry can help confirm the diagnosis. About evaluating the potential severity of some lung diseases, the exercise test can also be useful, observing a series of parameters, such as the ratio of forced expiratory volume in 1 second/forced vital capacity (FEV1/FVC). The severity of the disease can still be classified based on FEV1 when it is below the lower limit of normal (ranging from mild when ≥70% of predicted to very severe when <35% of predicted). Although HF itself can lead to a decrease in FEV1 and FVC of about 20% of predicted, in addition to the fact that a worse FEV1 may predict higher mortality, convincing evidence examining the prognostic role of FEV1 in the HF setting still needs further investigation.
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