Strzelczyk T A, Cusick D A, Pfeifer P B, Bondmass M D, Quigg R J
Division of Cardiology, Northwestern University Medical School, Northwestern Memorial Hospital, Chicago, Ill., USA.
Am Heart J. 2001 Sep;142(3):466-75. doi: 10.1067/mhj.2001.117508.
Peak exercise oxygen consumption (peak VO2) is an important discriminator of survival in patients with systolic heart failure and is used to select ambulatory patients for transplantation. The major trials assessing the relationship between peak VO2 and survival have used a variety of low-level exercise protocols. It is unknown how peak VO2 measured in this patient population by the more vigorous Bruce treadmill protocol compares with that obtained on less intense protocols.
We studied 15 patients (50 +/- 12 years old) with severe heart failure (left ventricular ejection fraction 23.5% +/- 8.6%). Patients randomly performed 3 exercise tests with the Bruce treadmill, modified Naughton treadmill, and modified bicycle protocols within 14 days. To determine the ability of this patient population to perform the Bruce protocol, we also retrospectively analyzed the ability of 84 patients to perform this test on their initial evaluations at our center.
All patients reached the anaerobic threshold (AT) on all 3 protocols. The Bruce and modified Naughton treadmill protocols resulted in similar peak VO2 percent predicted peak VO2, and VO2 at AT values (17.7 +/- 3.8 mL/kg/min, 57.2% +/- 21.1% and 15.4 +/- 4.1 mL/kg/min vs 18.0 +/- 4.7 mL/kg/min, 58.1% +/- 22.5% and 15.6 +/- 4.4 mL/kg/min, respectively). Peak VO2 and VO2 at AT on both treadmill protocols were higher than those obtained with bicycle testing (15.3 +/- 3.1 and 11.8 +/- 3.0 mL/kg/min, P <.05). Exercise duration was shorter with the Bruce and bicycle protocols (6.2 +/- 2.2 and 6.7 +/- 2.4 minutes, respectively) compared with the modified Naughton protocol (9.7 +/- 4.3 minutes, both P <.005). In addition, 79 of the 84 patients (94%) evaluated were able to complete the Bruce protocol and reach AT.
The Bruce protocol was more time efficient than the modified Naughton protocol and yielded similar peak VO2, percent predicted peak VO2, and VO2 at AT values. Bicycle exercise may underestimate peak VO2 values. The form of exercise should be considered when assessing peak VO2 criteria for transplant listing.
运动峰值耗氧量（峰值VO₂）是收缩性心力衰竭患者生存的重要判别指标，用于选择适合门诊移植的患者。评估峰值VO₂与生存关系的主要试验采用了各种低强度运动方案。目前尚不清楚在这一患者群体中，通过更剧烈的布鲁斯跑步机方案测得的峰值VO₂与在强度较低的方案中测得的峰值VO₂相比如何。
我们研究了15例重度心力衰竭患者（年龄50±12岁，左心室射血分数23.5%±8.6%）。患者在14天内随机采用布鲁斯跑步机、改良诺顿跑步机和改良自行车方案进行3次运动测试。为了确定这一患者群体执行布鲁斯方案的能力，我们还回顾性分析了84例患者在我们中心初次评估时执行该测试的能力。
所有患者在所有3种方案中均达到无氧阈值（AT）。布鲁斯和改良诺顿跑步机方案得出的预测峰值VO₂百分比、峰值VO₂以及AT值时的VO₂相似（分别为17.7±3.8 mL/kg/min、57.2%±21.1%和15.4±4.1 mL/kg/min，与18.0±4.7 mL/kg/min、58.1%±22.5%和15.6±4.4 mL/kg/min）。两种跑步机方案的峰值VO₂和AT值时的VO₂均高于自行车测试得出的值（15.3±3.1和11.8±3.0 mL/kg/min，P<.05）。与改良诺顿方案（9.7±4.3分钟）相比，布鲁斯和自行车方案的运动持续时间较短（分别为6.2±2.2和6.7±2.4分钟，P均<.005）。此外，84例接受评估的患者中有79例（94%）能够完成布鲁斯方案并达到AT。
布鲁斯方案比改良诺顿方案更省时，且得出的峰值VO₂、预测峰值VO₂百分比以及AT值时的VO₂相似。自行车运动可能会低估峰值VO₂值。在评估移植名单的峰值VO₂标准时，应考虑运动形式。
