Lee H H, Dávila-Román V G, Ludbrook P A, Courtois M, Walsh J F, Delano D A, Rubin P J, Gropler R J
Department of Internal Medicine, Washington University School of Medicine, St Louis, Mo, USA.
Circulation. 1997 Nov 4;96(9):2884-91. doi: 10.1161/01.cir.96.9.2884.
Contractile reserve, improvement in contractile function during inotropic stimulation, is a proposed marker of viable myocardium. This study was designed to address, in patients with left ventricular dysfunction due to chronic coronary artery disease, whether contractile reserve depends on myocardial blood flow.
We studied 19 patients, at rest and during dobutamine, with 2D echocardiography for regional mechanical function and PET for regional myocardial blood flow ([(15)O]water) and oxygen consumption ([11C]acetate). Of 166 myocardial segments, 21 had normal systolic function, 56 were dysfunctional but contractile reserve-positive, and 89 were dysfunctional and contractile reserve-negative. Myocardial blood flow at rest was lower in contractile reserve-negative (0.41+/-0.18 mL x g(-1) x min(-1)) than in contractile reserve-positive (0.50+/-0.22 mL x g(-1) x min(-1)) and normal segments (0.55+/-0.20 mL x g(-1) x min(-1), P<.009). After dobutamine infusion, blood flow increased less in contractile reserve-negative (0.63+/-0.38 mL x g(-1) x min(-1)) than in contractile reserve-positive (1.28+/-0.65 mL x g(-1) x min(-1)) and normal segments (1.93+/-0.83 mL x g(-1) x min(-1), P<.0001). Likewise, myocardial oxygen consumption was lower at rest in contractile reserve-negative (clearance rate of [11C]acetate, 0.043+/-0.012 min(-1)) than in contractile reserve-positive (0.048+/-0.01 min(-1)) and normal segments (0.058+/-0.008 min(-1), P<.02). Myocardial oxygen consumption with dobutamine increased less in contractile reserve-negative (0.060+/-0.013 min(-1)) than in contractile reserve-positive (0.077+/-0.016 min(-1)) and normal segments (0.092+/-0.024 min(-1), P<.0001). Of segments defined as viable by PET, 54% were contractile reserve-negative and exhibited lower blood flow with dobutamine (0.72+/-0.36 mL x g(-1) x min(-1)) than with viable, contractile reserve-positive segments (1.29+/-0.70 mL x g(-1) x min(-1), P<.0001).
Contractile reserve depends, in part, on the level of myocardial blood flow at rest and during inotropic stimulation.
收缩储备，即变力刺激期间收缩功能的改善，是一种被提出的存活心肌标志物。本研究旨在探讨在慢性冠状动脉疾病导致左心室功能障碍的患者中，收缩储备是否依赖于心肌血流。
我们对19例患者在静息状态和多巴酚丁胺输注期间进行了研究，采用二维超声心动图评估局部机械功能，采用正电子发射断层扫描（PET）评估局部心肌血流（[¹⁵O]水）和氧消耗（[¹¹C]乙酸盐）。在166个心肌节段中，21个节段收缩功能正常，56个节段功能异常但收缩储备阳性，89个节段功能异常且收缩储备阴性。收缩储备阴性节段静息时的心肌血流（0.41±0.18 mL·g⁻¹·min⁻¹）低于收缩储备阳性节段（0.50±0.22 mL·g⁻¹·min⁻¹）和正常节段（0.55±0.20 mL·g⁻¹·min⁻¹，P<0.009）。多巴酚丁胺输注后，收缩储备阴性节段的血流增加量（0.63±0.38 mL·g⁻¹·min⁻¹）低于收缩储备阳性节段（1.28±0.65 mL·g⁻¹·min⁻¹）和正常节段（1.93±0.83 mL·g⁻¹·min⁻¹，P<0.0001）。同样，收缩储备阴性节段静息时的心肌氧消耗（[¹¹C]乙酸盐清除率，0.043±0.012 min⁻¹）低于收缩储备阳性节段（0.048±0.01 min⁻¹）和正常节段（0.058±0.008 min⁻¹，P<0.02）。多巴酚丁胺刺激下收缩储备阴性节段的心肌氧消耗增加量（0.060±0.013 min⁻¹）低于收缩储备阳性节段（0.077±0.016 min⁻¹）和正常节段（0.092±0.024 min⁻¹，P<0.0001）。在PET定义为存活的节段中，54%为收缩储备阴性，多巴酚丁胺刺激下其血流（0.72±0.36 mL·g⁻¹·min⁻¹）低于存活且收缩储备阳性的节段（1.29±0.70 mL·g⁻¹·min⁻¹，P<0.0001）。
收缩储备部分取决于静息状态和变力刺激期间的心肌血流水平。
