Chintala Kavitha, Epstein Michael L, Singh Tajinder P
Division of Cardiology, Carman Ann Adams Department of Pediatrics, Children's Hospital of Michigan, Wayne State University School of Medicine, Detroit, MI 48201, USA.
Pediatr Cardiol. 2008 Jan;29(1):60-4. doi: 10.1007/s00246-007-9046-6. Epub 2007 Sep 5.
Interpretation of change in exercise performance over time in children with repaired congenital heart disease is often hampered by poor effort that limits the maximum heart rate; this is often difficult to distinguish from chronotropic impairment, a common finding in these children. In an attempt to address this limitation, we sought to examine measures of exercise performance that are corrected for heart rate in healthy children and to determine if these change with somatic growth. We studied two serial graded exercise tests in 24 healthy children at an interval of >3 years. Paired comparisons revealed that maximum oxygen pulse (O(2) pulse), O(2) pulse at ventilatory anaerobic threshold, O(2) pulse at a heart rate of 140 beats per minute, and slope of the VO(2)-heart rate relationship all increased with age. However, when indexed to somatic growth, there was no change in the mean values of these parameters over time. We conclude that O(2 )pulse and slope of the VO(2)-heart rate relationship during exercise increase in proportion to somatic growth in children so that optimal oxygen delivery to the exercising muscles is ensured. This study provides the "normative" response of exercise parameters to growth, against which responses of children with repaired congenital heart disease may be compared.
先天性心脏病修复术后儿童运动能力随时间的变化解读常常因努力程度不足限制了最大心率而受到阻碍；这往往难以与变时性功能不全相区分，而变时性功能不全在这些儿童中很常见。为解决这一局限性，我们试图研究在健康儿童中经心率校正的运动能力指标，并确定这些指标是否随体格生长而变化。我们对24名健康儿童进行了两次间隔超过3年的连续分级运动试验。配对比较显示，最大氧脉搏、通气无氧阈时的氧脉搏、心率为每分钟140次时的氧脉搏以及VO₂-心率关系斜率均随年龄增加。然而，按体格生长进行指数化后，这些参数的平均值随时间并无变化。我们得出结论，儿童运动期间的氧脉搏和VO₂-心率关系斜率与体格生长成比例增加，从而确保向运动肌肉最佳输氧。本研究提供了运动参数对生长的“正常”反应，可用于比较先天性心脏病修复术后儿童的反应。
