Cardiac output changes during exercise in heart failure patients: focus on mid-exercise.

This dataset contains the raw data of the paper "Cardiac output changes during exercise in heart failure patients: focus on mid-exercise."

Aims: Peak exercise oxygen uptake (VO2 ) and cardiac output (CO) are strong prognostic indexes in heart failure (HF) but unrelated to real-life physical activity, which is associated to submaximal effort.

Methods and results: We analysed maximal cardiopulmonary exercise test with rest, mid-exercise, and peak exercise non-invasive CO measurements (inert gas rebreathing) of 231 HF patients and 265 healthy volunteers. HF patients were grouped according to exercise capacity (peak VO2 < 50% and ≥50% pred, Groups 1 and 2). To account for observed differences, data regarding VO2 , CO, stroke volume (SV), and artero-venous O2 content difference [ΔC(a-v)O2 ] were adjusted by age, gender, and body mass index. A multiple regression analysis was performed to predict peak VO2 from mid-exercise cardiopulmonary exercise test and CO parameters among HF patients. Rest VO2 was lower in HF compared with healthy subjects; meanwhile, Group 1 patients had the lowest CO and highest ΔC(a-v)O2 . At mid-exercise, Group 1 patients achieved a lower VO2 , CO, and SV [0.69 (interquartile range 0.57-0.80) L/min; 5.59 (4.83-6.67) L/min; 62 (51-73) mL] than Group 2 [0.94 (0.83-1.1) L/min; 7.6 (6.56-9.01) L/min; 77 (66-92) mL] and healthy subjects [1.15 (0.93-1.30) L/min; 9.33 (8.07-10.81) L/min; 87 (77-102) mL]. Rest to mid-exercise SV increase was lower in Group 1 than Group 2 (P = 0.001) and healthy subjects (P < 0.001). At mid-exercise, ΔC(a-v)O2 was higher in Group 2 [13.6 (11.8-15.4) mL/100 mL] vs. healthy patients [11.6 (10.4-13.2) mL/100 mL] (P = 0.002) but not different from Group 1 [13.6 (12.0-14.9) mL/100 mL]. At peak exercise, Group 1 patients achieved a lower VO2 , CO, and SV than Group 2 and healthy subjects. ΔC(a-v)O2 was the highest in Group 2. At multivariate analysis, a model comprising mid-exercise VO2 , carbon dioxide production (VCO2 ), CO, haemoglobin, and weight predicted peak VO2 , P < 0.001. Mid-exercise VO2 and CO, haemoglobin, and weight added statistically significantly to the prediction, P < 0.050.

Conclusions: Mid-exercise VO2 and CO portend peak exercise values and identify severe HF patients. Their evaluation could be clinically useful.

本数据集包含论文《心力衰竭患者运动中心输出量变化：聚焦运动中期》的原始数据。

研究目的：最大运动摄氧量（VO2）与心输出量（Cardiac Output, CO）是心力衰竭（Heart Failure, HF）患者的重要预后指标，但二者与现实生活中以亚极量运动为主的体力活动并无关联。

方法与结果：本研究纳入231名心力衰竭患者与265名健康志愿者，采用惰性气体重复呼吸法，对其静息、运动中期及极量运动阶段的无创心输出量检测数据结合最大心肺运动试验进行分析。根据运动能力将心力衰竭患者分为两组：1组为峰值摄氧量<50%预计值者，2组为峰值摄氧量≥50%预计值者。为校正混杂因素，研究对摄氧量、心输出量、每搏输出量（Stroke Volume, SV）以及动静脉血氧含量差[ΔC(a-v)O2]等指标，按年龄、性别与体质量指数进行了校正。随后开展多元回归分析，基于心力衰竭患者的运动中期心肺运动试验参数与心输出量相关指标预测其峰值摄氧量。
结果显示：心力衰竭患者的静息摄氧量低于健康受试者；其中1组患者的心输出量最低，动静脉血氧含量差最高。运动中期阶段，1组患者的摄氧量[0.69（四分位距0.57~0.80）L/min]、心输出量[5.59（4.83~6.67）L/min]与每搏输出量[62（51~73）mL]均低于2组患者[分别为0.94（0.83~1.1）L/min、7.6（6.56~9.01）L/min、77（66~92）mL]与健康受试者[分别为1.15（0.93~1.30）L/min、9.33（8.07~10.81）L/min、87（77~102）mL]。1组患者静息至运动中期的每搏输出量增幅低于2组（P=0.001）与健康受试者（P<0.001）。运动中期阶段，2组患者的动静脉血氧含量差[13.6（11.8~15.4）mL/100mL]高于健康受试者[11.6（10.4~13.2）mL/100mL]（P=0.002），但与1组患者[13.6（12.0~14.9）mL/100mL]无统计学差异。极量运动阶段，1组患者的摄氧量、心输出量与每搏输出量均低于2组患者与健康受试者；2组患者的动静脉血氧含量差最高。多元回归分析显示，包含运动中期摄氧量、二氧化碳生成量（VCO2）、心输出量、血红蛋白与体质量的预测模型可有效预测峰值摄氧量（P<0.001）；其中运动中期摄氧量、心输出量、血红蛋白与体质量对预测模型的贡献具有统计学意义（P<0.050）。

结论：运动中期的摄氧量与心输出量可预示极量运动阶段的相关指标，并可识别重度心力衰竭患者，其临床评估具有一定应用价值。