Centro Cardiologico Monzino, IRCCS, Milan, Italy.
Department of Clinical Sciences and Community Health, Cardiovascular Section, University of Milan, Via Parea, 4-20138, Milan, Italy.
ESC Heart Fail. 2022 Apr;9(2):812-821. doi: 10.1002/ehf2.13781. Epub 2021 Dec 30.
Cardiopulmonary exercise test (CPET) and 6 min walking test (6MWT) are frequently used in heart failure (HF). CPET is a maximal exercise, whereas 6MWT is a self-selected constant load test usually considered a submaximal, and therefore safer, exercise, but this has not been tested previously. The aim of this study was to compare the cardiorespiratory parameters collected during CPET and 6MWT in a large group of healthy subjects and patients with HF of different severity.
Subjects performed a standard maximal CPET and a 6MWT wearing a portable device allowing breath-by-breath measurement of cardiorespiratory parameters. HF patients were grouped according to their CPET peak oxygen uptake (peakV̇O ). One hundred and fifty-five subjects were enrolled, of whom 40 were healthy (59 ± 8 years; male 67%) and 115 were HF patients (69 ± 10 years; male 80%; left ventricular ejection fraction 34.6 ± 12.0%). CPET peakV̇O was 13.5 ± 3.5 mL/kg/min in HF patients and 28.1 ± 7.4 mL/kg/min in healthy subjects (P < 0.001). 6MWT-V̇O was 98 ± 20% of the CPET peakV̇O values in HF patients, while 72 ± 20% in healthy subjects (P < 0.001). 6MWT-V̇O was >110% of CPET peakV̇O in 42% of more severe HF patients (peakV̇O < 12 mL/kg/min). Similar results have been found for ventilation and heart rate. Of note, the slope of the relationship between V̇O at 6MWT, reported as a percentage of CPET peakV̇O vs. 6MWT V̇O reported as the absolute value, progressively increased as exercise limitation did.
In conclusion, the last minute of 6MWT must be perceived as a maximal or even supramaximal exercise activity in patients with more severe HF. Our findings should influence the safety procedures needed for the 6MWT in HF.
心肺运动测试（CPET）和 6 分钟步行测试（6MWT）常用于心力衰竭（HF）。CPET 是一种最大运动，而 6MWT 是一种自我选择的恒定负荷测试，通常被认为是亚最大的，因此更安全，但这一点以前没有得到过验证。本研究的目的是比较大量健康受试者和不同严重程度 HF 患者在 CPET 和 6MWT 期间收集的心肺参数。
受试者佩戴允许逐口气测量心肺参数的便携式设备进行标准最大 CPET 和 6MWT。根据 CPET 峰值摄氧量（peakV̇O）将 HF 患者分为不同的组。共纳入 155 例受试者，其中 40 例为健康受试者（59±8 岁；男性占 67%），115 例为 HF 患者（69±10 岁；男性占 80%；左心室射血分数 34.6±12.0%）。HF 患者的 CPET 峰值 V̇O 为 13.5±3.5 mL/kg/min，健康受试者为 28.1±7.4 mL/kg/min（P<0.001）。HF 患者 6MWT-V̇O 为 CPET 峰值 V̇O 的 98±20%，而健康受试者为 72±20%（P<0.001）。42%病情更严重的 HF 患者（peakV̇O<12 mL/kg/min）的 6MWT-V̇O 超过 110%的 CPET 峰值 V̇O。对于通气和心率也得到了类似的结果。值得注意的是，6MWT 时 V̇O 与 CPET 峰值 V̇O 之间的关系斜率，以 6MWT 时的百分比表示，与 6MWT 时的绝对值表示的 V̇O 呈递增关系，随着运动受限程度的增加而增加。
总之，在病情更严重的 HF 患者中，6MWT 的最后 1 分钟必须被视为最大或甚至超最大运动活动。我们的研究结果应该影响 HF 患者进行 6MWT 所需的安全程序。
