Bleeker Gabe B, Kaandorp Theodorus A M, Lamb Hildo J, Boersma Eric, Steendijk Paul, de Roos Albert, van der Wall Ernst E, Schalij Martin J, Bax Jeroen J
Department of Cardiology, Leiden University Medical Center, Leiden, The Netherlands.
Circulation. 2006 Feb 21;113(7):969-76. doi: 10.1161/CIRCULATIONAHA.105.543678. Epub 2006 Feb 13.
Currently, one third of patients treated with cardiac resynchronization therapy (CRT) do not respond. Nonresponse to CRT may be explained by the presence of scar tissue in the posterolateral left ventricular (LV) segments, which may result in ineffective LV pacing and inadequate LV resynchronization. In the present study, the relationship between transmural posterolateral scar tissue and response to CRT was evaluated.
Forty consecutive patients with end-stage heart failure (NYHA class III/IV), LV ejection fraction < or =35%, QRS duration >120 ms, left bundle-branch block, and chronic coronary artery disease were included. The localization and transmurality of scar tissue were evaluated with contrast-enhanced MRI. Next, LV dyssynchrony was assessed at baseline and immediately after implantation with tissue Doppler imaging. Clinical parameters, LV volumes, and LV ejection fraction were assessed at baseline and at a 6-month follow-up. Fourteen patients (35%) had a transmural (>50% of LV wall thickness) posterolateral scar. In contrast to patients without posterolateral scar tissue, these patients showed a low response rate (14% versus 81%; P<0.05) and did not show improvement in clinical or echocardiographic parameters. In addition, LV dyssynchrony remained unchanged after CRT implantation (84+/-46 versus 78+/-41 ms; P=NS). Patients without posterolateral scar tissue and severe baseline dyssynchrony (> or =65 ms) showed an excellent response rate of 95% compared with patients with a posterolateral scar and/or absent LV dyssynchrony (11%).
CRT does not reduce LV dyssynchrony in patients with transmural scar tissue in the posterolateral LV segments, resulting in clinical and echocardiographic nonresponse to CRT.
目前，接受心脏再同步治疗（CRT）的患者中有三分之一无反应。CRT无反应可能是由于左心室（LV）后外侧节段存在瘢痕组织，这可能导致LV起搏无效和LV再同步不足。在本研究中，评估了透壁性后外侧瘢痕组织与CRT反应之间的关系。
纳入40例终末期心力衰竭（纽约心脏协会III/IV级）、LV射血分数≤35%、QRS时限>120 ms、左束支传导阻滞且患有慢性冠状动脉疾病的连续患者。用对比增强MRI评估瘢痕组织的定位和透壁性。接下来，在基线和植入后即刻用组织多普勒成像评估LV不同步。在基线和6个月随访时评估临床参数、LV容积和LV射血分数。14例患者（35%）有透壁性（>LV壁厚度的50%）后外侧瘢痕。与没有后外侧瘢痕组织的患者相比，这些患者的反应率较低（14%对81%；P<0.05），并且临床或超声心动图参数没有改善。此外，CRT植入后LV不同步仍未改变（84±46对78±41 ms；P=无显著性差异）。没有后外侧瘢痕组织且基线严重不同步（≥65 ms）的患者显示出95%的优异反应率，而有后外侧瘢痕和/或无LV不同步的患者为11%。
CRT不能减少LV后外侧节段有透壁瘢痕组织患者的LV不同步，导致临床和超声心动图对CRT无反应。
