Sorrentino M J, Marcus R H, Lang R M
Department of Medicine, University of Chicago Hospitals, Illinois 60637, USA.
Clin Cardiol. 1996 Mar;19(3):225-30. doi: 10.1002/clc.4960190317.
Hypotension has been found to occur in more than one-third of patients during DBSE. Unlike traditional treadmill exercise stress testing, hypotension does not appear to be associated with significant coronary artery disease or left ventricular (LV) dysfunction. Several ischemic and nonischemic mechanisms such as dynamic LV intracavitary obstruction have been implicated in the pathogenesis of hypotension and the induction of symptoms during DBSE.
The purpose of this study was the prospective evaluation of patients referred for dobutamine stress echocardiography (DBSE) to determine (1) the frequency of hypotension during DBSE, (2) the underlying mechanisms responsible for the induction of hypotension, and (3) to describe the cardiac chamber sizes and mass of patients in whom hypotension occurs.
Seventy-eight consecutive patients were studied during DBSE. Pulsed and continuous-wave Doppler echocardiography were performed at baseline and at each dobutamine infusion stage. Maximum velocities were recorded. Cardiac output was determined noninvasively at each stage in patients who developed an outflow tract gradient. Echocardiography was used to characterize LV dimensions and mass.
During dobutamine infusion, 14 of 78 (18%) patients developed a left ventricular outflow tract (LVOT) velocity > or = 2.5 m/s. Pulsed Doppler echocardiography verified that the maximal velocity originated in the LVOT. Of the patients who developed an LVOT gradient, 57% had a concomitant hypotensive response to dobutamine compared with 33% of patients without a gradient (not significant). Four of nine patients had a simultaneous fall in cardiac output. Patients who developed an LVOT gradient had smaller LV dimensions and increased wall thicknesses compared with those who did not develop a gradient.
Dobutamine stress echocardiography precipitates LVOT obstruction in certain patients. The development of a gradient corresponded with a fall in blood pressure and a decline in cardiac output in nearly half of the patients. These findings suggest that stress-induced LVOT obstruction may be responsible in part for the hemodynamic changes and symptoms experienced by these patients during exercise.
已发现超过三分之一的患者在多巴酚丁胺负荷超声心动图（DBSE）检查期间出现低血压。与传统的跑步机运动负荷试验不同，低血压似乎与严重冠状动脉疾病或左心室（LV）功能障碍无关。几种缺血性和非缺血性机制，如动态左心室内腔梗阻，已被认为与DBSE期间低血压的发病机制和症状诱发有关。
本研究的目的是对接受多巴酚丁胺负荷超声心动图（DBSE）检查的患者进行前瞻性评估，以确定（1）DBSE期间低血压的发生率，（2）诱发低血压的潜在机制，以及（3）描述发生低血压患者的心脏腔室大小和质量。
对78例连续患者进行DBSE检查。在基线和每个多巴酚丁胺输注阶段进行脉冲和连续波多普勒超声心动图检查。记录最大速度。对出现流出道梯度的患者在每个阶段进行无创心输出量测定。超声心动图用于描述左心室大小和质量。
在多巴酚丁胺输注期间，78例患者中有14例（18%）出现左心室流出道（LVOT）速度≥2.5 m/s。脉冲多普勒超声心动图证实最大速度起源于LVOT。在出现LVOT梯度的患者中，57%对多巴酚丁胺有伴随的低血压反应，而无梯度患者为33%（无显著性差异）。9例患者中有4例同时心输出量下降。与未出现梯度的患者相比，出现LVOT梯度的患者左心室尺寸较小且壁厚增加。
多巴酚丁胺负荷超声心动图在某些患者中会诱发LVOT梗阻。梯度的出现与近一半患者的血压下降和心输出量减少相对应。这些发现表明，应激诱导的LVOT梗阻可能部分导致这些患者运动期间的血流动力学变化和症状。
