Pulmonary function at peak exercise in patients with chronic heart failure

Abstract Background Various respiratory abnormalities are associated with chronic heart failure (CHF). However, changes in inspiratory capacity (IC) and breathing pattern from rest to exercise in patients with CHF have not been thoroughly investigated in these patients. Materials and methods Seventy seven (66 male/11 female) patients with clinical stable CHF (age: 52±11 years) were studied. All the patients underwent pulmonary function tests, including measurements of IC and maximal inspiratory pressure (Pimax) at rest and then a maximal cardiopulmonary exercise testing (CPET) on a treadmill. During the CPET, IC was measured every 2 min. Pimax was measured again after the end of CPET. Results Percent predicted forced expiratory volume in 1 s (FEV 1 ) was 91±12, %predicted forced vital capacity (FVC) was 92±13, %FEV 1 /FVC was 81±4, and %predicted IC was 85±18. Peak exercise IC was lower than resting (2.4±0.6 vs. 2.6±0.6 l, p p V E / V CO 2 slope ( p p =0.005) and post-exercise Pimax( p 2 ( P etco2 ) ( p =0.002), in breathing frequency ( p =0.004), in inspiratory time (Ti) ( p =0.04) and in total respiratory time ( T Tot ) ( p =0.004) among Weber's groups. At peak exercise there was a statistically significant decrease in minute ventilation ( V E ) ( p V T ) ( p V T / T I ) ( p P etco2 ( p Peak IC was correlated with peak V O 2 ( r =0.72, p r =0.71, p V O 2 / t slope ( r =0.54, p r =0.62, p Conclusions In patients with CHF, peak exercise IC is reduced in parallel with disease severity, which is probably due to respiratory muscle dysfunction.