Inspiratory Muscle Training Improves Intercostal and Forearm Muscle Oxygenation in Patients With Chronic Heart Failure: Evidence of the Origin of the Respiratory Metaboreflex.

BACKGROUND: The impact of inspiratory muscle training (IMT) on respiratory and peripheral muscle oxygenation and perfusion during inspiratory muscle fatigue in patients with chronic heart failure (HF) has not been established. METHODS AND RESULTS: Twenty-six patients with chronic HF were randomly assigned to either 8 weeks of IMT or a control group. Inspiratory fatigue was induced by means of a progressive inspiratory resistive loading protocol until there was an inability to sustain inspiratory pressure, when the inspiratory muscle metaboreflex should be activated. The main outcomes were intercostal and forearm muscle oxygen saturation and deoxygenation as measured by means of near-infrared spectroscopy (NIRS) and blood lactate levels. Inspiratory muscle strength was increased by 78% (P <.001) after 8 weeks of participation in the IMT group. IMT attenuated the reduction of oxygen saturation in intercostal and forearm muscles and the increase in blood lactate during respiratory fatigue (P <.001 and P <.05, respectively). These changes were different from the control group (P <.01, P <.05, and P <.05, respectively). After 8 weeks, similar increases in oxygen consumption, mean arterial pressure, heart rate, stroke volume, and cardiac output were observed in both groups during respiratory fatigue. CONCLUSIONS: This randomized controlled clinical trial demonstrates that IMT attenuates the respiratory muscle oxygen demand-delivery mismatch during respiratory fatigue in patients with chronic HF.

Longitudinal evaluation the pulmonary function of the pre and postoperative periods in the coronary artery bypass graft surgery of patients treated with a physiotherapy protocol.

BACKGROUND: The treatment of coronary artery disease (CAD) seeks to reduce or prevent its complications and decrease morbidity and mortality. For certain subgroups of patients, coronary artery bypass graft surgery (CABG) may accomplish these goals. The objective of this study was to assess the pulmonary function in the CABG postoperative period of patients treated with a physiotherapy protocol. METHODS: Forty-two volunteers with an average age of 63 ± 2 years were included and separated into three groups: healthy volunteers (n = 09), patients with CAD (n = 9) and patients who underwent CABG (n = 20). Patients from the CABG group received preoperative and postoperative evaluations on days 3, 6, 15 and 30. Patients from the CAD group had evaluations on days 1 and 30 of the study, and the healthy volunteers were evaluated on day 1. Pulmonary function was evaluated by measuring forced vital capacity (FVC), maximum expiratory pressure (MEP) and Maximum inspiratory pressure (MIP). RESULTS: After CABG, there was a significant decrease in pulmonary function (p < 0.05), which was the worst on postoperative day 3 and returned to the preoperative baseline on postoperative day 30. CONCLUSION: Pulmonary function decreased after CABG. Pulmonary function was the worst on postoperative day 3 and began to improve on postoperative day 15. Pulmonary function returned to the preoperative baseline on postoperative day 30.

Coronary artery bypass surgery and longitudinal evaluation of the autonomic cardiovascular function.

INTRODUCTION: Imbalance in autonomic cardiovascular function increases the risk for sudden death in patients with coronary artery disease (CAD), but the time course of the impact of coronary artery bypass grafting (CABG) on autonomic function has been little studied. Thus, the purpose of the present study was to determine the effects of the CABG on the cardiovascular autonomic function. METHODS: Patients undergoing CABG (n = 13) and two matched control groups (patients with CAD who refused surgical treatment [n = 9], and healthy volunteers [n = 9]) underwent a prospective longitudinal study consisting of autonomic evaluation before and after (3, 6, 15, 30, 60, and 90 days) surgery, including measurement of heart rate variability (HRV), respiratory sinus arrhythmia (RSA), and Valsalva maneuver. RESULTS: After CABG there was a decrease in, and a later recovery of, (1) the HRV in the time domain and in the frequency domain, (2) RSA, and (3) Valsalva maneuver. CONCLUSIONS: CABG caused an impairment, reversible after 60 days, of cardiovascular autonomic function, with a maximal decrease on about the sixth day after surgery.