Niemeijer Victor M, Spee Ruud F, Schoots Thijs, Wijn Pieter F F, Kemps Hareld M C
Department of Cardiology, Máxima Medical Centre, Veldhoven, the Netherlands;
Department of Applied Physics, Eindhoven University of Technology, Eindhoven, the Netherlands; and.
Am J Physiol Heart Circ Physiol. 2016 Dec 1;311(6):H1530-H1539. doi: 10.1152/ajpheart.00474.2016. Epub 2016 Oct 7.
The extent and speed of transient skeletal muscle deoxygenation during exercise onset in patients with chronic heart failure (CHF) are related to impairments of local O delivery and utilization. This study examined the physiological background of submaximal exercise performance in 19 moderately impaired patients with CHF (Weber class A, B, and C) compared with 19 matched healthy control (HC) subjects by measuring skeletal muscle oxygenation (SmO) changes during cycling exercise. All subjects performed two subsequent moderate-intensity 6-min exercise tests (bouts 1 and 2) with measurements of pulmonary oxygen uptake kinetics and SmO using near-infrared spatially resolved spectroscopy at the vastus lateralis for determination of absolute oxygenation values, amplitudes, kinetics (mean response time for onset), and deoxygenation overshoot characteristics. In CHF, deoxygenation kinetics were slower compared with HC (21.3 ± 5.3 s vs. 16.7 ± 4.4 s, P < 0.05, respectively). After priming exercise (i.e., during bout 2), deoxygenation kinetics were accelerated in CHF to values no longer different from HC (16.9 ± 4.6 s vs. 15.4 ± 4.2 s, P = 0.35). However, priming did not speed deoxygenation kinetics in CHF subjects with a deoxygenation overshoot, whereas it did reduce the incidence of the overshoot in this specific group (P < 0.05). These results provide evidence for heterogeneity with respect to limitations of O delivery and utilization during moderate-intensity exercise in patients with CHF, with slowed deoxygenation kinetics indicating a predominant O utilization impairment and the presence of a deoxygenation overshoot, with a reduction after priming in a subgroup, indicating an initial O delivery to utilization mismatch.
慢性心力衰竭（CHF）患者运动开始时短暂骨骼肌脱氧的程度和速度与局部氧输送和利用受损有关。本研究通过测量骑自行车运动期间骨骼肌氧合（SmO）变化，比较了19例中度受损的CHF患者（Weber A、B和C级）与19例匹配的健康对照（HC）受试者次最大运动表现的生理背景。所有受试者进行两次连续的中等强度6分钟运动测试（第1轮和第2轮），使用近红外空间分辨光谱法测量股外侧肌的肺氧摄取动力学和SmO，以确定绝对氧合值、幅度、动力学（起始平均反应时间）和脱氧过冲特征。在CHF患者中，与HC相比，脱氧动力学较慢（分别为21.3±5.3秒和16.7±4.4秒，P<0.05）。在预运动后（即第2轮期间），CHF患者的脱氧动力学加速至与HC不再有差异的值（16.9±4.6秒和15.4±4.2秒，P=0.35）。然而，预运动并未加快有脱氧过冲的CHF患者的脱氧动力学，而它确实降低了该特定组中过冲的发生率（P<0.05）。这些结果为CHF患者在中等强度运动期间氧输送和利用限制方面的异质性提供了证据，脱氧动力学减慢表明主要存在氧利用受损，并且存在脱氧过冲，在一个亚组中预运动后过冲减少，表明最初存在氧输送与利用不匹配。
