Siddiqui Tariq S, Dawn Buddhadeb, Stoddard Marcus F
Division of Cardiology, Department of Medicine, University of Louisville, Louisville, Kentucky 40292, USA.
J Am Soc Echocardiogr. 2006 Sep;19(9):1144-9. doi: 10.1016/j.echo.2006.04.018.
The mechanism of hypotension during dobutamine stress (DS) echocardiography is unknown. The role of left ventricular outflow tract (OT) or midcavitary (MID) obstruction provoked during stress in this process remains controversial. We hypothesized that left ventricular OT obstruction would account for hypotension as opposed to MID obstruction.
Multiplane DS transesophageal echocardiography (TEE) was performed in 142 adult patients who displayed no resting obstruction or DS-provoked ischemia. TEE was used to identify the precise site of obstruction. Dobutamine was infused from 5 to 40 microg/kg/min and atropine as needed. Continuous wave Doppler was performed from appropriate views to assess for obstruction.
Ventricular obstruction was provoked at the OT in 13 patients, MID in 10 patients, and at both sites in 4 patients. A total of 115 patients without dobutamine-induced obstruction served as control subjects. Systolic blood pressure at rest was similar in all groups, but decreased to a greater magnitude from rest to peak stress in the OT (-20 +/- 40 mm Hg) and MID (-29 +/- 38 mm Hg) groups as compared with the control group (8 +/- 30 mm Hg). A hypotensive response (ie, decrease in systolic blood pressure > or = 20 mm Hg from baseline to peak stress) was significantly greater in OT (69%, P = .001) and MID (60%, P < .05) groups as compared with the control group (19%). Heart rate and ejection fraction at rest or peak did not differ among groups. Among clinical and hemodynamic variables, left ventricular OT (relative risk 5.9; 95% confidence interval 1.9-18; P < .002) and MID (relative risk 3.6; 95% confidence interval 1.1-12; P < .05) obstructions were the only predictors for a hypotensive response.
Hypotension during DS TEE occurs commonly when ventricular obstruction is provoked. These data support a causal relationship between a provoked ventricular obstruction and hypotension during DS TEE.
多巴酚丁胺负荷试验（DS）超声心动图检查期间发生低血压的机制尚不清楚。应激过程中引发的左心室流出道（OT）或心腔中部（MID）梗阻在此过程中的作用仍存在争议。我们假设左心室OT梗阻而非MID梗阻是导致低血压的原因。
对142例静息时无梗阻或DS诱发缺血的成年患者进行多平面DS经食管超声心动图（TEE）检查。TEE用于确定梗阻的确切部位。多巴酚丁胺以5至40微克/千克/分钟的速度静脉输注，并根据需要使用阿托品。从适当的视图进行连续波多普勒检查以评估梗阻情况。
13例患者在OT处诱发心室梗阻，10例患者在MID处诱发梗阻，4例患者在两个部位均诱发梗阻。共有115例未发生多巴酚丁胺诱发梗阻的患者作为对照。所有组静息时的收缩压相似，但与对照组（8±30毫米汞柱）相比，OT组（-20±40毫米汞柱）和MID组（-29±38毫米汞柱）从静息到应激峰值时收缩压下降幅度更大。与对照组（19%）相比，OT组（69%，P = 0.001）和MID组（60%，P < 0.05）的低血压反应（即收缩压从基线到应激峰值下降≥20毫米汞柱）明显更常见。各组静息或峰值时的心率和射血分数无差异。在临床和血流动力学变量中，左心室OT梗阻（相对风险5.9；95%置信区间1.9 - 18；P < 0.002）和MID梗阻（相对风险3.6；95%置信区间1.1 - 12；P < 0.05）是低血压反应的唯一预测因素。
DS TEE检查期间，当诱发心室梗阻时低血压很常见。这些数据支持DS TEE检查期间诱发的心室梗阻与低血压之间存在因果关系。
