Prolonged mean VO2 response time in systolic heart failure: an indicator of impaired right ventricular-pulmonary vascular function.
Prolonged mean VO2 response time in systolic heart failure: an indicator of impaired right ventricular-pulmonary vascular function.
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DOI：
10.1161/circheartfailure.112.000157
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发表时间：
2013-05
期刊：
影响因子：
--
通讯作者：
Lewis GD
中科院分区：
文献类型：
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作者：
Chatterjee NA;Murphy RM;Malhotra R;Dhakal BP;Baggish AL;Pappagianopoulos PP;Hough SS;Semigran MJ;Lewis GD
在左心室收缩功能障碍(LVSD)患者中，运动开始时摄氧量(VO2)增加的速度不足以满足代谢需求。为了从机制上深入了解LVSD的延迟VO2动力学，我们同时评估了运动中的血流动力学测量、呼吸参数和外周氧气利用。对42例有症状的LVSD患者(平均年龄59±2岁，左心室射血分数(LVEF)30±1%)和17例对照组(LVEF 68±1%)进行最大立位功率心肺运动试验(CPET)。静息和运动时进行血流动力学监测和首次核素脑室造影术。用平均反应时间来量化VO2动力学，与对照组相比，LVSD患者的平均反应时间明显延长(±3秒对45±5秒(S)，p=0.004)。在LVSD患者中，MRT与早期运动时较高的双室充盈压和较低的心输出量相关。与≥60S组相比，运动时右室-肺血管(RV-PV)功能受损程度更大，表现为右室射血分数降低(35±2vs.45±2%，p=0.03)，跨肺梯度与心输出量之比增大(3.7vs.2.2，p<；0.001)，呼吸机死腔分数增加(17±1vs.12±2%，p=0.03)。相比之下，MRT与LVEF(休息、运动)、PaO2、血红蛋白或静息肺功能测试结果无关。LVSD患者开始运动时的延迟摄氧量(即MRT≥60s)与RV-PV功能受损密切相关，可能是心力衰竭患者在体力活动中无法增强RV性能的重要替代指标。
In patients with left ventricular systolic dysfunction (LVSD), the rate at which oxygen uptake (VO2) increases upon initiation of exercise is inadequate to match metabolic demands. To gain mechanistic insights into delayed VO2 kinetics in LVSD we simultaneously assessed hemodynamic measurements, ventilatory parameters, and peripheral oxygen utilization during exercise. 42 patients with symptomatic LVSD (age 59±2 years [mean±SEM], LV ejection fraction (LVEF) 30±1%) and 17 controls (LVEF 68±1%) underwent maximum upright cycle ergometry cardiopulmonary exercise testing (CPET). Hemodynamic monitoring and first-pass radionuclide ventriculography were performed at rest and during exercise. VO2 kinetics were quantified by mean response time (MRT), which was significantly longer in patients with LVSD compared to controls (64±3 vs. 45±5 seconds (s), p =0.004). In LVSD patients, MRT was associated with higher biventricular filling pressures and reduced cardiac output during early exercise. LVSD patients with MRT≥60s, compared to LVSD subjects with MRT<60s, demonstrated greater impairment in right ventricular-pulmonary vascular (RV-PV) function during exercise as evidenced by lower RVEF (35±2 vs. 45±2%, p=0.03), steeper increment in trans-pulmonary gradient relative to cardiac output (3.7 vs. 2.2, p<0.001), and increased ventilatory dead-space fraction (17±1 vs. 12±2%, p=0.03). In contrast, MRT was not associated with LVEF (rest, exercise), PaO2, hemoglobin, or resting pulmonary function test results. Delayed oxygen uptake upon initiation of exercise (i.e. MRT ≥60s) in LVSD is closely related to impaired RV-PV function and may represent an important surrogate for inability to augment RV performance during physical activity in patients with HF.