Engels Elien B, Poels Thomas T, Houthuizen Patrick, de Jaegere Peter P T, Maessen Jos G, Vernooy Kevin, Prinzen Frits W
Department of Physiology, CARIM School for Cardiovascular Diseases, Maastricht University, Maastricht, The Netherlands.
Department of Cardiothoracic Surgery, Maastricht University Medical Center, Maastricht, The Netherlands.
Europace. 2016 Dec;18(suppl 4):iv44-iv52. doi: 10.1093/europace/euw350.
Left bundle branch block (LBBB) is induced in approximately one-third of all transcatheter aortic valve implantation (TAVI) procedures. We investigated electrophysiological remodelling in patients with TAVI-induced LBBB.
This retrospective study comprises 107 patients with initially narrow QRS complex of whom 40 did not and 67 did develop persistent LBBB after TAVI. 12-lead electrocardiograms (ECGs) taken before TAVI, within 24 hours ('acute'), and 1-12 months after TAVI ('chronic') were used to reconstruct vectorcardiograms. From these vectorcardiograms, QRS and T-wave area were calculated as comprehensive indices of depolarization and repolarization abnormalities, respectively. TAVI-induced LBBB resulted in significant acute depolarization and repolarization changes while further repolarization changes were observed with longer lasting LBBB. The amount of long-term repolarization changes (remodelling) was highly variable between patients. The change in T-wave area between acute and chronic LBBB ranged from +57% to - 77%. After dividing the LBBB cohort into tertiles based on the change in T-wave area, only baseline QRS area was larger in the tertile with no significant change in T-wave area. During longer lasting LBBB, the spatial vector gradient (SVG) changed orientation towards the direction of the QRS-vector, indicating that later-activated regions developed shorter action potential duration.
This study in patients with TAVI-induced LBBB shows that repolarization changes develop within months after onset of LBBB, and that these changes are highly variable between individual patients.
在所有经导管主动脉瓣植入术（TAVI）中，约三分之一的患者会诱发左束支传导阻滞（LBBB）。我们研究了TAVI诱发LBBB患者的电生理重塑情况。
这项回顾性研究纳入了107例初始QRS波群狭窄的患者，其中40例在TAVI后未发生持续性LBBB，67例发生了持续性LBBB。利用TAVI术前、术后24小时内（“急性期”）以及术后1 - 12个月（“慢性期”）的12导联心电图（ECG）重建向量心电图。从这些向量心电图中，分别计算QRS波群和T波面积，作为去极化和复极化异常的综合指标。TAVI诱发的LBBB导致显著的急性去极化和复极化改变，而随着LBBB持续时间延长，还观察到进一步的复极化改变。患者之间长期复极化改变（重塑）的程度差异很大。急性和慢性LBBB之间T波面积的变化范围为 +57%至 -77%。根据T波面积变化将LBBB队列分为三分位数后，只有T波面积无显著变化的三分位数中的基线QRS波群面积更大。在持续时间更长的LBBB期间，空间向量梯度（SVG）的方向朝着QRS向量的方向改变，表明较晚激活的区域动作电位时程缩短。
这项针对TAVI诱发LBBB患者的研究表明，LBBB发作后数月内会出现复极化改变，且这些改变在个体患者之间差异很大。
