The Cardiovascular Institute, 3-10, Roppongi 7-chome, Minato-ku, Tokyo 106-0032, Japan.
J Physiol Sci. 2010 Mar;60(2):137-42. doi: 10.1007/s12576-009-0077-z.
The overshoot in oxygen uptake (VO2 overshoot) during recovery from maximal exercise is thought to reflect an overshoot in cardiac output. We investigated whether this phenomenon is related to cardiopulmonary function during exercise in cardiac patients. A total of 201 consecutive patients with previous myocardial infarction underwent cardiopulmonary exercise testing (CPX). An apparent VO2 overshoot during the recovery from CPX (6.5+/-8.1% increase relative to the peak VO2) was observed in ten patients. A comparison of patients with the VO2 overshoot to those without the VO2 overshoot revealed that the former had a significantly lower left ventricular ejection fraction (40.1+/-19.1 vs. 55. 2+/-14.9%, respectively, p = 0.002) and larger left ventricular diastolic and systolic dimensions. Patients with the VO2 overshoot also had a significantly lower peak VO2 (13.1+/-6.1 vs. 18.1+/-4.5 ml/min/kg, p < 0.001), lower DeltaVO2/DeltaWR (work rate) (6.6+/-3.8 vs. 9.5+/-1.7 mL/min/W, p < 0.0001), and a higher E (minute ventilation)/VCO2 (carbon dioxide output) slope (45.0+/-18.6 vs. 32.6+/-6.6, p < 0.0001) than those without the overshoot. A VO2 overshoot during recovery from maximal exercise was found in 5% of patients with previous myocardial infarction. This condition, which suggests a transient mismatch between cardiac contractility and afterload reduction, was found to be related to impaired cardiopulmonary function during exercise.
在最大运动恢复期，摄氧量（VO2 超射）的过度增加被认为反映了心输出量的过度增加。我们研究了这种现象是否与心肌梗死患者运动期间的心肺功能有关。共有 201 例连续前心肌梗死患者接受心肺运动测试（CPX）。在 10 例患者中观察到 CPX 恢复期（与峰值 VO2 相比增加 6.5+/-8.1%）的明显 VO2 超射。VO2 超射患者与无 VO2 超射患者的比较表明，前者的左心室射血分数明显较低（分别为 40.1+/-19.1%和 55.2+/-14.9%，p=0.002），左心室舒张和收缩尺寸较大。VO2 超射患者的峰值 VO2 也明显较低（分别为 13.1+/-6.1 和 18.1+/-4.5 ml/min/kg，p<0.001），DeltaVO2/DeltaWR（工作率）较低（分别为 6.6+/-3.8 和 9.5+/-1.7 mL/min/W，p<0.0001），E（分钟通气量）/VCO2（二氧化碳输出）斜率较高（分别为 45.0+/-18.6 和 32.6+/-6.6，p<0.0001）。在 5%的前心肌梗死患者中发现最大运动恢复期有 VO2 超射。这种情况表明心脏收缩性和后负荷降低之间存在短暂的不匹配，与运动期间心肺功能受损有关。
