骨骼肌代谢限制慢性心力衰竭患者的运动能力。

Skeletal muscle metabolism limits exercise capacity in patients with chronic heart failure.

作者信息

Okita K, Yonezawa K, Nishijima H, Hanada A, Ohtsubo M, Kohya T, Murakami T, Kitabatake A

机构信息

Department of Cardiovascular Medicine, Hokkaido University School of Medicine, and the Sapporo Health Promotion Center, Sapporo, Japan.

出版信息

Circulation. 1998 Nov 3;98(18):1886-91. doi: 10.1161/01.cir.98.18.1886.

DOI:10.1161/01.cir.98.18.1886

PMID:9799209

Abstract

BACKGROUND

Several studies have indicated that skeletal muscle is important in determining the exercise capacity of patients with chronic heart failure (CHF). However, this theory has been investigated only in experiments based on local exercise involving a small muscle mass. We investigated skeletal muscle metabolism during maximal systemic exercise to determine whether muscle metabolism limits exercise capacity in patients with CHF. We also studied the relationship between muscle metabolic abnormalities during local and systemic exercise.

METHODS AND RESULTS

Skeletal muscle metabolism was measured during maximal systemic exercise on a bicycle ergometer by a combination of the metabolic freeze method and 31P magnetic resonance spectroscopy in 12 patients with CHF and 7 age- and size-matched normal subjects. We also evaluated skeletal muscle metabolism during local exercise while subjects performed unilateral plantar flexion. Muscle phosphocreatine (PCr) was nearly depleted during maximal systemic exercise in patients with CHF and normal subjects (12.5+/-0.04% and 12.3+/-0.07%, respectively, of initial level). PCr depletion occurred at a significantly lower peak oxygen uptake (peak VO2) in patients with CHF than in normal subjects (CHF, 20.2+/-3.0 versus normal, 31.8+/-3.7 mL . min-1 . kg-1, P<0. 0001). Muscle metabolic capacity, evaluated as the slope of PCr decrease in relation to increasing workload, was correlated with peak VO2 during maximal systemic exercise in patients with CHF (r=0.83, P<0.001). Muscle metabolic capacity during local exercise was impaired in patients with CHF and was correlated with capacity during systemic exercise (r=0.76, P<0.01) and with peak VO2 (r=0. 83, P<0.001).

CONCLUSIONS

These results suggest that impaired muscle metabolism associated with early metabolic limitation determines exercise capacity during maximal systemic exercise in patients with CHF. There was a significant correlation between muscle metabolic capacity during systemic and local exercise in patients with CHF.

摘要

背景

多项研究表明，骨骼肌在决定慢性心力衰竭（CHF）患者的运动能力方面具有重要作用。然而，该理论仅在涉及小肌肉量的局部运动实验中得到研究。我们研究了最大全身运动期间的骨骼肌代谢，以确定肌肉代谢是否限制CHF患者的运动能力。我们还研究了局部和全身运动期间肌肉代谢异常之间的关系。

方法与结果

采用代谢冻结法和31P磁共振波谱技术，在12例CHF患者和7例年龄及体型匹配的正常受试者进行自行车测力计最大全身运动期间，测量骨骼肌代谢。我们还在受试者进行单侧跖屈时评估了局部运动期间的骨骼肌代谢。在CHF患者和正常受试者的最大全身运动期间，肌肉磷酸肌酸（PCr）几乎耗尽（分别为初始水平的12.5±0.04%和12.3±0.07%）。CHF患者的PCr耗尽发生时的峰值摄氧量（peak VO2）显著低于正常受试者（CHF组为20.2±3.0，正常组为31.8±3.7 mL·min-1·kg-1，P<0.0001）。以PCr下降斜率与工作量增加的关系评估的肌肉代谢能力，与CHF患者最大全身运动期间的peak VO2相关（r=0.83，P<0.001）。CHF患者局部运动期间的肌肉代谢能力受损，且与全身运动期间的能力相关（r=0.76，P<0.01），与peak VO2相关（r=0.83，P<0.001）。