Aerobic capacity and skeletal muscle fatigue in coronary artery disease patients

Objective. - The aim of this study is to determine if the diminished aerobic capacity of coronary artery disease patients is accompanied by a impaired peripheral skeletal muscle function compared to healthy control subjects. Methods. - Thirteen coronary patients and 9 healthy control subjects (57 +/- 7 vs 55 +/- 8 years) have realised both a maximal laboratory exercise testing and an assessment of the peripheral skeletal muscle function on a isokinetic apparatus (Cybex Norm II). The cardiorespiratory and mechanical parameters (VO2 uptake, VE, HR and Power output) were measured at ventilatory threshold and maximal effort during a cycloergeometer testing. The peripheral skeletal muscle function of the quadriceps was assessed from the maximal voluntary isometric force (MVIF) and from static endurance time (SET) at an intensity of 50% of the MVIF Results. - Coronary patients showed a diminished aerobic capacity at maximal effort (VO2max: 23.56 +/- 8.1 vs 42.43 +/- 9.74 ml min(-1) kg(-1), p < 0.0001; VEmax: 67.07 +/- 16.85 vs 90.15 +/- 20.761 min(-1), p < 0.01; HRmax : 110 +/- 17 vs 153 +/- 20 beats min(-1), p < 0.0001; P-max: 133 +/- 40 vs 233 +/- 39 W,p < 0,001) but also at ventilatory threshold (VO2: 15.81 +/- 5.7 vs 29.61 +/- 7.8 ml min(-1) kg(-1),p < 0.001; HR: 92+/-11 vs 135+/-21 beats.min(-1), p < 0.0001, P: 88 +/- 32 vs 153 +/- 39,W p < 0.001) except for VE (VE: 38.98 +/- 9.91 vs 46.68 +/- 7.031 min(-1), NS). No difference was found between the MVIF (MVIF: 230 +/- 46 vs 228 +/- 21 N m(-1), NS) between coronary patients and control subjects whereas the SET is lower in coronary patients (65 +/- 19 vs 88 +/- 9 s, p < 0.003). Conclusion. - Coronary artery disease patients have a lower aerobic capacity accompanied by a impaired peripheral skeletal muscle function. (C) 2003 Editions scientifiques et medicales Elsevier SAS. All rights reserved.