van Dijk J, Mannaerts H F J, Germans T, Hauer H A, Knaapen P, Visser C A, Kamp O
Neth Heart J. 2006 Nov;14(11):372-380.
Left bundle branch block (LBBB) is related to abnormal cardiac conduction and mechanical asynchrony and is associated with hypertension and coronary artery disease. Improved evaluation of left ventricular (LV) mechanical asynchrony is needed, because of the increasing number of patients with LBBB and heart failure. In this paper, we describe tissue Doppler imaging (TDI), strain (rate) imaging and tissue tracking in LBBB patients. A variety of patterns of mechanical activation can be observed in LBBB patients. A recent development, referred to as tissue synchronisation imaging, colour codes TDI time-to-peak systolic velocities of segments and displays mechanical asynchrony. Furthermore, real-time 3D echocardiography provides new regional information about mechanical asynchrony. Contained in an LV model and projected on a bull's eye plot, this modality helps to display the spatial distribution of mechanical asynchrony. Finally, segmental time-to-peak circumferential strain curves, produced by cardiac magnetic resonance imaging, provide additional quantification of LV mechanical asynchrony. Effects of LBBB on regional and global cardiac function are impressive, myocardial involvement seems to play a role and with the help of these novel imaging modalities, new insights continue to develop.
左束支传导阻滞（LBBB）与心脏传导异常和机械性不同步有关，且与高血压和冠状动脉疾病相关。鉴于LBBB患者和心力衰竭患者数量不断增加，需要对左心室（LV）机械性不同步进行更好的评估。在本文中，我们描述了LBBB患者的组织多普勒成像（TDI）、应变（率）成像和组织追踪。在LBBB患者中可观察到多种机械激活模式。最近发展起来的一种方法，即组织同步成像，通过颜色编码各节段的TDI收缩期峰值速度时间，并显示机械性不同步情况。此外，实时三维超声心动图提供了有关机械性不同步的新的区域信息。包含在左心室模型中并投影到靶心图上，这种方法有助于显示机械性不同步的空间分布。最后，心脏磁共振成像生成的节段性峰值圆周应变曲线提供了左心室机械性不同步的额外量化指标。LBBB对局部和整体心脏功能的影响显著，心肌受累似乎起了作用，借助这些新的成像方法，新的见解不断涌现。
