Tanaka Hidekazu, Tatsumi Kazuhiro, Matsumoto Kensuke, Kawai Hiroya, Hirata Ken-ichi
Division of Cardiovascular Medicine, Department of Internal Medicine, Kobe University Graduate School of Medicine, Kobe, Japan.
Echocardiography. 2013 Oct;30(9):E292-5. doi: 10.1111/echo.12280. Epub 2013 Jun 6.
A case was 53-year-old female with dilated-phase hypertrophic cardiomyopathy. She was classified as New York Heart Association functional class III heart failure despite receiving optimal medical therapy. The electrocardiogram taken showed intraventricular conduction delay with a QRS width of 194 msec. The left ventricular (LV) end-diastolic and systolic volumes, and ejection fraction (EF) were 101 mL, 68 mL, and 32%, respectively. The patient showed no significant mechanical LV dyssynchrony as evidenced by two-dimensional (2D) speckle tracking radial strain, which is defined as the time difference between anterior-septum and posterior wall, of 105 msec (<130 msec). Three-dimensional (3D) speckle tracking radial strain was performed for more detailed LV mechanical dyssynchrony analysis. An especially important finding for 3D speckle tracking radial strain analysis was that the average time-to-peak strain of 5 septum segments at 3 different LV levels (basal-anterior-septum, basal-septum, mid-anterior-septum, mid-septum, apical-septum) was significantly shorter than that of 5 posterolateral segments at 3 different LV levels (basal-posterior, basal-lateral, mid-posterior, mid-lateral, apical-lateral). This time difference between septum and posterolateral wall was 216 msec (204 msec vs. 420 msec), which was considered to indicate significant LV mechanical dyssynchrony (≥130 msec). 12 months after cardiac resynchronization therapy (CRT), EF had improved to 47%, while end-systolic and diastolic volumes had decreased to 88 mL and 47 mL, respectively, so that the patient was classified as a responder. In conclusions, a newly developed 3D speckle tracking strain can provide a comprehensive evaluation of "true" LV mechanical dyssynchrony from pyramidal 3D data sets acquired in the same beat, thus yielding more accurate information than previously possible with the 2D speckle tracking system.
一名53岁女性患有扩张期肥厚型心肌病。尽管接受了最佳药物治疗，但她仍被归类为纽约心脏协会心功能III级心力衰竭。所做的心电图显示室内传导延迟，QRS宽度为194毫秒。左心室舒张末期和收缩末期容积以及射血分数（EF）分别为101毫升、68毫升和32%。二维（2D）斑点追踪径向应变显示该患者无明显的左心室机械不同步，该应变定义为前间隔与后壁之间的时间差，为105毫秒（<130毫秒）。进行三维（3D）斑点追踪径向应变以进行更详细的左心室机械不同步分析。3D斑点追踪径向应变分析的一个特别重要的发现是，在左心室3个不同水平（基底前间隔、基底间隔、中间前间隔、中间间隔、心尖间隔）的5个间隔节段的平均达峰应变时间明显短于左心室3个不同水平（基底后壁、基底侧壁、中间后壁、中间侧壁、心尖侧壁）的5个后外侧节段的平均达峰应变时间。间隔与后外侧壁之间的这个时间差为216毫秒（204毫秒对420毫秒），这被认为表明存在明显的左心室机械不同步（≥130毫秒）。心脏再同步治疗（CRT）12个月后，EF提高到47%，而收缩末期和舒张末期容积分别降至88毫升和47毫升，因此该患者被归类为反应者。总之，新开发的3D斑点追踪应变可以从同一心动周期采集的金字塔形3D数据集中对“真正的”左心室机械不同步进行全面评估，从而产生比以前二维斑点追踪系统所能获得的更准确的信息。
