Respiratory drive and breathing pattern abnormalities are related to exercise intolerance in chronic heart failure patients

Abstract Background Patients with chronic heart failure (CHF) are characterized by exercise intolerance and ventilatory abnormalities that are related to poor prognosis. We hypothesized that CHF patients have increased respiratory drive and abnormal breathing pattern during exercise in relation to disease severity. Materials and methods The study population consisted of 219 stable CHF patients and 30 healthy control subjects. All subjects underwent a symptom-limited cardiopulmonary exercise testing (CPET), pulmonary function tests, measurement of the maximal inspiratory pressure ( P I max ) and respiratory drive ( P 0.1 ). Measurements included peak oxygen uptake ( V O 2 peak, ml/kg/min). Respiratory drive was measured by mouth occlusion pressure P 0.1 and P 0.1 / P I max ratio at rest, and by mean inspiratory flow ( V T / T I ) at rest and during exercise. CHF patients were divided into 3 groups according to V O 2 peak (Group A: >20, Group B: 20–16 and Group C: Results CHF patients presented higher P 0.1 / P I max (4.1 ± 3.6 vs 3.0 ± 1.5, p  = 0.007) and V T / T I at rest (0.48 ± 0.14 vs 0.41 ± 0.10, L/s respectively, p  = 0.004) and lower V T / T I at peak exercise (2.17 ± 0.66 vs 2.56 ± 0.73, L/s, p  = 0.009) compared to controls. P 0.1 / P I max was higher in CHF Group C vs B vs A (4.9 ± 2.9 vs 3.6 ± 1.8 vs 3.1 ± 1.8, respectively, p V T / T I at peak exercise was lower (1.71 ± 0.43 vs 2.15 ± 0.52 vs 2.65 ± 0.64, L/s, respectively, p Conclusions CHF patients present increased respiratory drive at rest and abnormal breathing pattern during exercise in relation to CHF severity.