Regional chest wall volume variations in heart failure patients during inspiratory muscle training

It is unknown how heart failure (HF) and cardiomegaly associated with diaphragmatic weakness affects chest wall function. Therefore, we evaluated in these patients the distribution of volume variations into the different thoracoabdominal compartments during quiet breathing and during inspiratory muscle training. Thirty-one individuals were evaluated and divided into two groups: HF (17 patients with functional class II and III chronic heart failure associated with cardiomegaly) and control (12 healthy volunteers). All subjects were evaluated by spirometry, six-minute walking test (6MWT), and optoelectronic plethysmography (OEP) during threshold inspiratory muscle training (IMT). OEP allowed to assess right-left asymmetries in the volume changes of upper thoracic (Vrcp), lower thoracic (Vrca), and abdominal (Vab) compartments. While no significant differences were present between right and left sides in the control group during IMT, in HF patients volume variations of Vrca were 45.30%±9.10 and 54.33%±12.9, respectively in the left and right sides (p=0,03). This was associated to a significant decrease, compared to normals, of Vrca variations; in addition, a positive correlation between the%Vra,left and ejection fraction of left ventricle (r=0.468 and p=0.049), and a negative correlation between the Borg scale after the 6MWT and the%Vra, left side (r=-0.878 and p