Respiratory Muscle Strength and Quality of Life in Patients With Heart Failure and Their Main Correlated Factors: A Cross-sectional Study.

Background: Heart failure may cause peripheral and respiratory muscle alterations, dyspnea, fatigue, and exercise intolerance, worsening the quality of life of patients.

Objectives: The aims of this study were to analyze respiratory muscle strength and quality of life of patients with heart failure and correlate them with clinical variables and functional classification.

Methods: This cross-sectional study involved patients with heart failure. A manovacuometer assessed maximum inspiratory and expiratory pressures, and quality of life was assessed using the Minnesota Living with Heart Failure Questionnaire. Functional classification was categorized according to the New York Heart Association (NYHA) class in I, II, III, or IV.

Results: We included 60 patients (66.7% male) with a mean age of 62.0 years and mean left ventricular ejection fraction of 42.0%. Maximum inspiratory pressure and maximum expiratory pressure were close to normal (>70% of predicted) in most patients; however, a subgroup composed mostly of patients with dilated heart failure and NYHA class III (n = 21) presented low maximum inspiratory pressure values (59.2%; 95% confidence interval, 55.7%-62.8%). The mean total score of the Minnesota Living with Heart Failure Questionnaire was 44.4 points, being negatively correlated with left ventricular ejection fraction ( r = -0.29, P = .02). Patients with NYHA class III and disease duration longer than 120 months presented higher total ( P < .01) and physical dimension scores.

Conclusions: Most patients had respiratory muscle strength close to normal; however, those with dilated heart failure and NYHA class III presented low maximum inspiratory pressure values. Quality of life was moderately compromised, mainly because of long disease duration, NYHA class III, and low left ventricular ejection fraction.