Objectives We investigated echocardiographic characteristics,pathogeny,and clinical values of midventricular obstruction(MVO). Methods The study population included 73 patients. MVO was diagnosed when the peak midcavitary gradient was estimated to be≧25mm Hg. Results MVO was identified in 25 patients with hypertrophic cardiomyopathy(HCM)and 48 with non-HCM. Peak systolic velocity obtained by continuous-wave Doppler averaged 3.11 m/s and appeared as either a "late-peaking"or a "spike and dome" configuration. No significant difference were found at MVO(3.08±0.74 VS 3.09±0.70,P=0.97),and significant difference were found at heart rate(74.04±8.56 VS 92.12±20.96,P=0.01),interventricular septum thickness (19.12±7.27 vs 11.63±2.07,P≤0.01)and left atriaum dimension(42.16±5.70 vs 39.14±5.95,=0.04)between HCM and non-HCM. In non-HCM patients,25 were hypertension,4 had sigmoid left ventricular septum,19 had unstable hemodynamics. Conclusions Echocardiography plays an important role for diagnosing MVO. Hypertension,unstable hemodynamics,excessive sympathetic activation,and inotropic agents are the main causes for MVO.% 目的分析左室腔中部梗阻（MVO）的超声心动图特点，探讨超声心动图诊断MVO及其病因的临床价值。方法对73例左室腔中部血流速度≥2.5m/s（最大压差≥25mm Hg）患者资料进行分析。结果（1）25例肥厚型心肌病（HCM）与48例非HCM患者左室腔中部均测及特征性收缩中期失落呈刀锋状频谱图，左室中部平均流速3.11 m/s。（2）HCM组与非HCM组比，室间隔厚度（19.12±7.27）mm与（11.63±2.07）mm，差异有统计学意义（P<0.01）；左房大小（42.16±5.70）mm与（39.14±5.95）mm，差异有统计学意义（P=0.04）；左室腔中部流速（3.08±0.74）m/s与（3.09±0.70）m/s，差异无统计学意义（P=0.97）；非HCM组心室率（92.12±20.96）次/min，显著快于HCM组的（74.04±8.56）次/min，差异有统计学意义（P=0.01）；非HCM组出现低血压及使用去甲肾上腺素、多巴胺者明显多于HCM组。（3）分析非HCM致MVO原因，高血压25例，S形室间隔4例，其他血流动力学不稳定19例。结论超声心动图对诊断MVO具有重要价值。高血压心脏病、血流动力学不稳定、交感过度激活及正性肌力药是非HCM致MVO的主要原因。
展开▼
