Brassard Patrice, Maltais Francois, Noel Martin, Doyon Jean-François, LeBlanc Pierre, Allaire Joakim, Simard Clermont, Leblanc Marie-Hélène, Poirier Paul, Jobin Jean
Centre de recherche, Hôpital Laval, Institut universitaire de cardiologie et de pneumologie, Université Laval, Ste-Foy, Québec, Canada.
Can J Cardiol. 2006 Apr;22(5):387-92. doi: 10.1016/s0828-282x(06)70923-0.
Alterations in skeletal muscle function are known to contribute to exercise intolerance in patients with chronic heart failure (CHF).
To evaluate whether muscle isometric endurance can be objectively measured and whether it is related to skeletal muscle metabolism in CHF.
Isometric endurance of the vastus lateralis, measured as time to fatigue (T(F)), was evaluated in 25 patients with CHF (55+/-8 years of age [mean +/- SD]) and 18 healthy subjects (HS) (62+/-6 years of age [mean +/- SD]). Median frequency of surface electromyography was obtained from spectral analysis using a fast Fourier transformation. Citrate synthase (CS), 3-hydroxyacyl-CoA dehydrogenase (HADH), hexokinase (HK) and phosphofructokinase (PFK) activities were determined from the right vastus lateralis muscle.
T(F) was lower in CHF patients than in HS (49+/-4 s and 80+/-7 s, respectively; P<0.01). Muscle fatigue was present at the end of the endurance test in both groups (median frequency breakpoint at mid-exercise for both groups [P<0.05]). CS (P<0.01) and HK (P<0.01) activities were lower in CHF patients than in HS, but PFK activity was higher (P<0.05). T(F) correlated significantly with CS (r=0.50), HADH (r=0.42), PFK (r=-0.47) and HK (r=0.41) activities and the PFK/CS ratio (r=-0.39) when both groups were considered, and with HADH (r=0.47) and PFK (r=-0.57) activities for the CHF group alone (all P<0.05).
These results suggest that isometric endurance of the vastus lateralis muscle is reduced in patients with CHF and that it is related to a reduced muscle oxidative capacity.
已知慢性心力衰竭（CHF）患者骨骼肌功能改变会导致运动不耐受。
评估CHF患者的肌肉等长耐力是否能够客观测量，以及它是否与骨骼肌代谢相关。
对25例CHF患者（年龄55±8岁[均值±标准差]）和18名健康受试者（HS）（年龄62±6岁[均值±标准差]）的股外侧肌等长耐力进行评估，以疲劳时间（T(F)）作为衡量指标。使用快速傅里叶变换通过频谱分析获得表面肌电图的中位频率。测定右侧股外侧肌的柠檬酸合酶（CS）、3-羟酰基辅酶A脱氢酶（HADH）、己糖激酶（HK）和磷酸果糖激酶（PFK）活性。
CHF患者的T(F)低于HS（分别为49±4秒和80±7秒；P<0.01）。两组在耐力测试结束时均出现肌肉疲劳（两组运动中期的中位频率断点[P<0.05]）。CHF患者的CS（P<0.01）和HK（P<0.01）活性低于HS，但PFK活性更高（P<0.05）。当将两组一起考虑时，T(F)与CS（r=0.50）、HADH（r=0.42）、PFK（r=-0.47）和HK（r=0.41）活性以及PFK/CS比值（r=-0.39）显著相关，单独对于CHF组，T(F)与HADH（r=0.47）和PFK（r=-0.57）活性相关（所有P<0.05）。
这些结果表明，CHF患者股外侧肌的等长耐力降低，且与肌肉氧化能力降低有关。
