Background

Apical transverse motion (ATM) is associated with electromechanical dyssynchrony in adult dilated cardiomyopathy (DCM). Bundle branch block electromechanical dyssynchrony is uncommon in pediatric DCM, but ATM and its association with ventricular function have not been characterized.

Methods

Fifty-six children with DCM were retrospectively studied. Using echocardiography, ATM was assessed visually and by speckle-tracking longitudinal displacement of the interventricular septal and left ventricular (LV) lateral walls in opposite directions. Doppler tissue imaging–derived displacement and velocities were used to time the onset and peak LV and right ventricle motion, from which intra- and interventricular delays were calculated to assess their association with ATM. The timing of aortic valve opening and closure in relation to onset and peak LV displacement was used as a measure of LV mechanical efficiency.

Results

LV ATM was observed in 35 of 56 patients (62.5%), occurring in two patterns: 45% had ATM (interventricular septum displacing toward the lateral wall and lateral wall displacing toward the mitral annulus during systole), and 18% showed reverse ATM (r-ATM; lateral wall displaced toward the apex and interventricular septum displaced toward the septal annulus during systole). Both patterns were associated with increased interventricular but not intraventricular mechanical delay (controls: 2 msec, ATM 16 msec, r-ATM 8 msec, both P < .05 vs control subjects). Patients with ATM or r-ATM had lower LV ejection fractions (19% vs 29%, P < .05) and higher mechanical inefficiency compared with those without ATM. Survival was not statistically different in those with ATM or r-ATM compared with those without ATM or r-ATM.

Conclusions

In pediatric DCM, ATM is associated with LV dysfunction, mechanical inefficiency, and interventricular mechanical delay.

中文翻译：

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扩张型心肌病患儿的心尖部横向运动与室间机械延迟和左心室功能降低相关

背景

在成人扩张型心肌病（DCM）中，心尖横向运动（ATM）与机电不同步相关。束支传导阻滞机电不同步在儿科DCM中并不常见，但是ATM及其与心室功能的关系尚未得到表征。

方法

回顾性研究了56例DCM儿童。使用超声心动图，通过视觉和通过斑点跟踪在相反方向上的室间隔和左心室（LV）侧壁的纵向位移来评估ATM。利用多普勒组织成像得出的位移和速度来确定左室起搏，左室峰值和右心室运动的时间，并据此计算出脑室内和脑室延迟，以评估其与ATM的相关性。主动脉瓣打开和关闭的时间与发作和左室峰值位移相关的时间用作左室机械效率的量度。

结果

在56例患者中的35例（62.5％）中观察到了LV ATM，其发生方式有两种：45％的患者有ATM（在收缩期室间隔向侧壁移位而侧壁向二尖瓣环移位），而18％的患者则显示了反向ATM（ r-ATM；在收缩期，侧壁向心尖移位，室间隔向室间隔移位）。两种模式均与室间隔增加有关，但与脑室内机械延迟无关（对照：2毫秒，ATM 16毫秒，r-ATM 8毫秒， 与对照组相比均P <.05）。患有ATM或r-ATM的患者左室射血分数较低（P分别为19％和29％ <.05），并且与没有ATM的机器相比，机械效率更高。与没有ATM或r-ATM的患者相比，有ATM或r-ATM的患者的生存率无统计学差异。

结论

在小儿DCM中，ATM与左室功能障碍，机械效率低下和心室机械性延迟有关。