Addition of inspiratory muscle training to aerobic training improves cardiorespiratory responses to exercise in patients with heart failure and inspiratory muscle weakness

Background This small clinical trial tested the hypothesis that the addition of inspiratory muscle training (IMT) to aerobic exercise training (AE) results in further improvement in cardiorespiratory responses to exercise than those obtained with AE in patients with chronic heart failure (CHF) and inspiratory muscle weakness (IMW). Methods Twenty-four patients with CHF and IMW (maximal inspiratory pressure <70% of predicted) were randomly assigned to a 12-week program of AE plus IMT (AE + IMT, n = 12) or to AE alone (AE, n = 12). Before and after intervention, the following measures were obtained: maximal inspiratory muscle pressure (PImax), peak oxygen uptake (VO(2)peak), peak circulatory power, oxygen uptake efficiency slope, ventilatory efficiency, ventilatory oscillation, oxygen uptake kinetics during recovery (T-1/2(V) over dot O-2), 6-minute walk test distance, and quality of life scores. Results Compared to AE, AE + IMT resulted in additional significant improvement in PImax (110% vs 72%), (V) over dot O(2)peak (40% vs 21%), circulatory power, oxygen uptake efficiency slope, ventilatory efficiency, ventilatory oscillation, and T-1/2 (V) over dot O-2. Six-minute walk distance and quality of life scores improved similarly in the 2 groups. Conclusion This randomized trial demonstrates that the addition of IMT to AE results in improvement in cardiorespiratory responses to exercise in selected patients with CHF and IMW. The clinical significance of these findings should be addressed by larger randomized trials. [Am Heart J 2009; 158:768.e1-768.e7.)