ABC | Volume 114, Nº4, April 2020

Original Article Marchese et al. Inspiratory exercise in heart failure Arq Bras Cardiol. 2020; 114(4):656-663 60% (C60) (67 ± 14 vs 73 ± 14 bpm, p=0.002), but did not change in the placebomode (P) (Figure 2). There was a decrease in SV when the IE was performed with C30 (73 ± 26 vs 64 ± 20 ml; p=0.004) and there were no changes with placebo and C60 (Figure 3). The DO increased when the IE was performed on C60 (4.6 ± 1.5 vs 5.3 ± 1.7 l/min; p=-0.001) and did not change with placebo and C30 (Figure 4). Responses of other hemodynamic variables to IE In addition to CHR, other hemodynamic variables also changed along the IE on the load C60. Placebo and C30 did not cause any changes in the variables presented. When the IE was performed on C60, there was an increase in systolic blood pressure (SBP) (124.1 ± 27.4 vs 130.6 ± 25.9 mmHg; p=0.001) (Figure 5), mean arterial pressure (MAP) (85.7 ± 17.9 vs 89.2 ± 17.3 mmHg, p=0.004) (Figure 6), as well as an increase in Borg scale of perceived exertion (0.3±0.9 vs 1.1±1.9, p=0.01) (Figure 7) and the subjective dyspnea scale (0.2±0.7 vs 0.8±1.5, p=0.02) (Figure 8). Correlation There was a moderate correlation between baseline CO and inspiratory muscle strength (r=0.45; p=0.04) (Figure 9). Discussion This is a pioneer study in describing changes in CHR with different IE loads in outpatients with HFREF, using a non- invasive method of hemodynamic monitoring. Different IMT strategies are used in clinical practice, but it is not clear which training intensity is the most efficient. Thereweredifferent hemodynamic behaviorswhen comparing placebo, 30% and 60% loads. Only the HR showed a similar response to IE with both loads of 30% and 60%, being increases. SV, on the other hand, had a significant drop only when the 30% load was used, and the CO increased only with the highest load, 60%. The control group (placebo) showed no significant change. In this study, the hypothesis that different IE loads could produce different central hemodynamic responses was tested. Although both HR 10 variability and the effects of respiratory muscle fatigue 11 after IMT have already been Figure 1 – CONSORT flowchart. 658