Respiratory muscle endurance is limited by lower ventilatory efficiency in post-myocardial infarction patients

Abstract

BackgroundReduced respiratory muscle endurance (RME) contributes to increased dyspnea upon exertion in patients with cardiovascular disease. ObjectiveThe objective was to characterize ventilatory and metabolic responses during RME tests in post-myocardial infarction patients without respiratory muscle weakness. MethodTwenty-nine subjects were allocated into three groups: recent myocardial infarction group (RG, n=9), less-recent myocardial infarction group (LRG, n=10), and control group (CG, n=10). They underwent two RME tests (incremental and constant pressure) with ventilatory and metabolic analyses. One-way ANOVA and repeated measures one-way ANOVA, both with Tukey post-hoc, were used between groups and within subjects, respectively. ResultsPatients from the RG and LRG presented lower metabolic equivalent and ventilatory efficiency than the CG on the second (50± 06, 50± 5 vs. 42± 4) and third part (50± 11, 51± 10 vs. 43± 3) of the constant pressure RME test and lower metabolic equivalent during the incremental pressure RME test. Additionally, at the peak of the incremental RME test, RG patients had lower oxygen uptake than the CG. ConclusionsPost-myocardial infarction patients present lower ventilatory efficiency during respiratory muscle endurance tests, which appears to explain their inferior performance in these tests even in the presence of lower pressure overload and lower metabolic equivalent.

Maximal expiratory pressure and Valsalva manoeuvre do not produce similar cardiovascular responses in healthy men

“…; Neves et al . ). The and the peak respiratory exchange ratio (RER), defined as the ratio between carbon dioxide production and oxygen uptake, were expressed as the highest averaged values observed during the last 30 s of the cardiopulmonary exercise test (Higa et al .…”

“…; Neves et al . ). The responses obtained during the cardiopulmonary exercise test at the ventilatory anaerobic threshold and peak exercise are shown in Table .…”

“…The ventilatory anaerobic threshold was identified by three independent experts using the V-slope method (Beaver et al 1986), and the oxygen uptake (V O 2 ) value at this point was considered as the mean of the data obtained from the three independent analyses (Beaver et al 1986;Balady et al 2010;Neves et al 2014). TheV O 2 peak and the peak respiratory exchange ratio (RER), defined as the ratio between carbon dioxide production and oxygen uptake, were expressed as the highest averaged values observed during the last 30 s of the cardiopulmonary exercise test (Higa et al 2007;Neves et al 2014). The responses obtained during the cardiopulmonary exercise test at the ventilatory anaerobic threshold and peak exercise are shown in Table 1.…”

Critical inspiratory pressure - new methodology for evaluating and training the inspiratory musculature for recreational cyclists: study protocol for a randomized control trial

“…The following will be considered: failure to maintain the stipulated load at 12 breaths/minute for at least 1 minute, failure to maintain respiratory effort indicated by the volunteer (BORG/CR10≥7) (36) and the participant requesting interruption. The highest percentage of MIP that the volunteer is able to maintain for at least 1 min (PThMÁX) will be stipulated as the RME measurement (26)(27)(28)47).…”

Reproducibility of inspiratory muscle endurance testing using PowerBreathe for COPD patients

“…This equipment is already being used for inspiratory muscle training for athletes and COPD patients (Beckerman, Magadle, Weiner, & Weiner, 2005;Volianitis et al, 2001). Moreover, it is also used to conduct inspiratory muscle endurance tests in patients with heart disease and COPD (Neves et al, 2012;Neves et al, 2014;Dias et al, 2013). However, its reproducibility has not been tested yet.…”