多巴酚丁胺负荷超声心动图对左心室流出道动力性梗阻的研究

The study of dynamic left ventricular outflow tract obstruction during dobutamine stress echocardiography

目的 应用多巴酚丁胺负荷超声心动图（DSE）检测左心室流出道血流速度，分析负荷后左心室流出道动力性梗阻的原因及其意义。方法 DSE检查待除外心肌缺血性疾病患者42例，分别于试验前后检测左心室流出道血流速度、压力阶差。试验中监测心电图、血压。试验后脱机分析。结果 DSE检查前42例患者左心室流出道血流速度均在正常范围，DSE达到峰值剂量后左心室流出道血流速度均增快，其中14例左心室流出道血流速度明显增快，大于215cm／s（218～627cm／s），压力阶差大于15mmHg（19．5～627．0mmHg，1mmHg=0．133kPa）。该14例患者均有左心室肥厚，其中不对称性以室间隔基底部肥厚为著者10例，对称性肥厚者4例。DSE试验仅3例同时出现心肌节段缺血改变。有明确高血压病史8例。相关分析显示，室间隔厚度与负荷后左心室流出道血流速度呈显著相关性，以室间隔基底肥厚更为显著（r=0．61，P〈0．001）。结论 DSE检测左心室流出道血流速度和压力阶差可明确左心室流出道梗阻，对基础状态左心室流出道压差正常、心室肥厚、临床症状明显者，DSE是明确左心室流出道动力性梗阻的重要手段。

Objective To evaluate the dynamic left ventricular outflow tract （LVOT） obstruction with dobutamine stress echocardiography （DSE）. Methods The flow velocity and gradient of LVOT were measured before and after DSE in 42 patients who suspected with myocardial is chemic diseases. All the patients were underwent continuous electrocardiogram and blood pressure interrogation to detect inducible hemodynamical disorder or cardiac ischemia. Results All patients had a normal flow velocity of LVOT before DSE and had an increased flow velocity under a peak dosage of DSE. The flow velocity of LVOT significantly increased in fourteen patients. The value of the flow velocity was greater than 215 cm/s （218-627 cm/s） and the gradient of LVOT was higher than 15 mm Hg （19.5-627.0 mm Hg, 1 mm Hg = 0. 133 kPa）. All of the 14 patients had left ventricular hypertrophy, including ten patients with asymmetric septal hypertrophy and four patients with symmetric septal hypertrophy. Only three patients were presented with cardiac segmental ischemia. Eight patients had confirmed hypertension. There was a significant correlation between septal thickness especially septal fundus hypertrophy and the flow velocity of LVOT（ r = 0. 61 , P 〈0. 001 ） . Conclusions The flow velocity and gradient of LVOT with DSE may be reliable parameters to determine dynamic LVOT obstruction in patients who have normal pressure in LVOT at baseline, ventricular hypertrophy and remarkable clinical symptoms. DSE is an important method as an inducement to the dynamic LVOT obstruction.