双频谱多普勒超声成像技术评价左心室乳头肌与附着室壁心肌机械力学时空关联性

目的运用双频谱多普勒超声成像技术评价左心室二尖瓣乳头肌与附着室壁心肌机械力学时空关联性。 方法选择2012年5至6月四川省人民医院经体格检查、心电图和超声心动图检查结果无异常，无高血压、心肌梗死、心脏瓣膜疾病及其他心血管疾病相关病史的健康志愿者112名。应用双频谱多普勒超声成像技术于心尖左心室长轴切面或心尖四腔心切面和心尖二腔心切面同步获取左心室二尖瓣前外侧乳头肌（APM）、后内侧乳头肌（PPM）中段及其乳头肌基底部所附着心室壁的心肌组织运动速度频谱，在同一心动周期内同步测量对应两位点心肌组织运动速度收缩期峰值速度（s′）、舒张早期峰值速度（e′）、舒张晚期峰值速度（a′），以心电图R波峰尖为时间起点，记录其对应达峰时间St、Et、At。采用配对t检验分别比较APM、PPM与其基底段附着室壁心肌组织、APM与PPM的s′、e′、a′、St、Et、At差异；采用Pearson相关分析分析APM、PPM与其基底段附着室壁心肌组织s′、e′、a′、St、Et、At的相关性及APM与PPM的St、Et、At的相关性。 结果与其基底段附着室壁心肌组织比较，APM的e′、a′均较高、s′均较低，且差异均有统计学意义（t值分别为-2.75、7.76、2.65，P均<0.01）；与其基底段附着室壁心肌组织比较，PPM的e′、a′均较高，且差异均有统计学意义（t值分别为11.74、3.31，P均<0.01）；s′的差异无统计学意义。与其基底部附着室壁心肌组织比较，APM、PPM的Et较小，且差异有统计学意义（t值分别为-8.57、-8.36，P均<0.01）；St、At的差异均无统计学意义。与APM比较，PPM的s′较低，St较长，且差异均有统计学意义（t值分别为2.74、-7.34，P均<0.01）；而e′、a′、Et、At差异均无统计学意义。APM与其基底段附着室壁s′、e′、a′均呈显著正相关（r=0.83、0.77、0.66，P均为0.000）；PPM与其基底段附着室壁s′、e′、a′也均呈显著正相关（r=0.86、0.81、0.79，P均为0.000）。APM与其基底段附着室壁St、Et、At均呈显著正相关（r=0.80、0.98、0.98，P均为0.000）；PPM与其基底段附着室壁St、Et、At也均呈显著正相关（r=0.82、0.99、1.00，P均为0.000）。APM与PPM的St、Et、At均呈显著正相关（r=0.34、0.91、0.88，P均为0.000）。 结论左心室APM、PPM与其附着室壁心肌运动状态存在一致的时空变化规律，两者间舒张期和收缩期心肌峰值运动速度存在差异；两组乳头肌间舒张期心肌峰值运动速度和达峰时间具有较高的同步性和相关性，收缩期心肌运动状态存在明显差异。

The spatio-temporal correlation of papillary muscular mechanics and adjacent left ventricular wall assessed by dual pulse-wave Doppler ultrasound imaging

ObjectiveTo study the spatio-temporal correlation of papillary muscular (PM) mechanics and adjacent left ventricle (LV) wall using ultrasonic dual pulse-wave Doppler (dual-PW) imaging. MethodsIn the study, 112 healthy volunteers without abnormalities on physical examination, electrocardiogram and echocardiogram and medical history of hypertension, myocardial infarction, valvular heart disease and other cardiovascular diseases were enrolled in May and June 2012 at Sichuan Provincial People′s Hospital. The velocity spectrum of tissue motion were synchronized and obtained at both the middle of PM and the bottom of its adjacent LV wall using dual-PW in the apical left ventricular long axis, four-chamber and two-chamber views. The measurements were simultaneously performed in the same cardiac cycle at two corresponding points for tissue velocity peak systolic velocity (s′), peak early diastolic velocity (e′), and late diastolic velocity (a′). And peak of R-wave on ECG was taken as the start point, which was used to record the time to peak of St, Et, At. ResultsCompared with the corresponding LV wall, it was significantly higher in e′ and a′, and s′ was significantly lower at anterolateral papillary muscle (APM) (t=-2.75, 7.76, 2.65, all P<0.01). Compared with the corresponding LV wall, it was significantly higher in e′ and a′ at posteromedial papillary muscle (PPM) (t=11.74, 3.31, both P<0.01), and there were not significant statistical difference in s′. Compared with the corresponding LV wall, it was much earlier for time to peak velocity at papillary muscle during the early diastole in two groups (t=-8.57, -8.36, both P<0.01). Compared with the anterolateral papillary muscle, it was longer for the systolic time to peak velocity of posterolateral papillary muscles, and lower for peak systolic velocity (t=2.74, -7.34, both P<0.01), and there were not significant statistical difference in St and At. There were significant correlations between diastolic peak velocity and time to peak velocity as well as between papillary muscles and the corresponding LV wall. There was a significant positive correlation of diastolic time to peak velocity between two PM groups. ConclusionsThere is a corresponding spatio-temporal relationship of myocardial mechanics between PM and adjacent LV wall. Meanwhile, tissue movement of PM were shown with a higher synchronization and correlation during diastole.