Acute and subacute hemodynamic responses and perception of effort in subjects with chronic Chagas cardiomyopathy submitted to different protocols of inspiratory muscle training: a cross-over trial

Purpose This study aimed to evaluate acute and subacute hemodynamic responses and perception of effort in individuals with CCC submitted to different IMT protocols. Materials and methods This was a randomized cross-over trial conducted on CCC subjects with systolic left ventricular dysfunction (<45% left ventricular ejection fraction) without or with heart failure (stages B2 and C, respectively). Twenty-one participants performed two IMT protocols, one targeting 60% maximal inspiratory pressure with 3 x 10 repetitions (MIP60) and the other targeting 30% maximal inspiratory pressure (MIP30) with 3 x 20 repetitions with a 2 min recovery between sets for both. MIP60 and MIP30 were performed on the same day with a 2 h washout period. Measurements were taken at baseline, during and 60 min after IMT. Results No differences in hemodynamic variables were observed across protocols. The perception of effort increased in both protocols, with higher scores for the MIP30 protocol (beta = +1.6,p = 0.01; beta = +1.1,p = 0.02; beta = +0.9,p = 0.08 for the 1st, 2nd and 3rd sets, respectively). Conclusions There were no differences in hemodynamic responses comparing MIP60 and MIP30 protocols in subjects with CCC. Despite the higher perception of effort during endurance protocol, both protocols can be considered a safe therapeutic strategy.