Heart Research Follow-Up Program, University of Rochester Medical Center, Rochester, NY, USA.
Am J Cardiol. 2013 Aug 15;112(4):525-9. doi: 10.1016/j.amjcard.2013.04.016. Epub 2013 May 29.
Cardiac resynchronization therapy (CRT) is effective for the treatment of patients with heart failure and a wide QRS duration, particularly left bundle branch block. However, subjects with right bundle branch block (RBBB) do not appear to benefit from CRT. The aim of this study was to determine whether patients with specific RBBB conduction patterns responded to CRT in the Multicenter Automatic Defibrillator Implantation Trial with Cardiac Resynchronization Therapy (MADIT-CRT) trial. In the present post hoc analysis, patients with RBBB who received CRT with an implantable cardioverter defibrillator (n = 132) were divided into 2 groups according to the baseline QRS morphology in the inferior and high lateral leads: group 1: left anterior fascicular block (LAFB) pattern (n = 80; 60.6%); and group 2: non-LAFB pattern (n = 52; 39.4%). Subjects with RBBB who received an implantable cardioverter defibrillator served as the control group (n = 87). The primary end point was echocardiographic response to CRT, defined as percent change in left ventricular (LV) and left atrial volumes from baseline to 1 year. The secondary end point was heart failure or death. The non-LAFB group demonstrated a significantly larger percent reduction in LV end-diastolic volume, LV end-systolic volume, and left atrial volume compared to controls (-11%, p <0.0001; -17%, p <0.0001; -15%, p <0.0001, respectively) and LAFB (-5%, p = 0.028; -7%, p = 0.019; -6%; p = 0.022; respectively) by multivariate analysis. No difference was found in the 3-year crude event rates for death or heart failure among the LAFB (22%), non-LAFB (21%), or ICD-only (20%) groups (p = NS). In conclusion, conduction patterns influence echocardiographic response to CRT in patients with RBBB, with favorable reductions in the LV and left atrial volumes in those without an LAFB conduction pattern. This echocardiographic benefit did not translate into a reduction in heart failure or death during a 3-year follow-up period.
心脏再同步治疗（CRT）对心力衰竭和宽 QRS 持续时间的患者，特别是左束支传导阻滞患者的治疗有效。然而，右束支传导阻滞（RBBB）患者似乎不能从 CRT 中获益。本研究旨在确定多中心自动除颤器植入试验中的 CRT 是否对具有特定 RBBB 传导模式的患者有效（MADIT-CRT 试验）。在本事后分析中，根据植入式心脏复律除颤器（ICD）治疗的 RBBB 患者下壁和高位侧壁导联的基线 QRS 形态，将患者分为 2 组：组 1：左前分支阻滞（LAFB）模式（n = 80；60.6%）；组 2：非 LAFB 模式（n = 52；39.4%）。RBBB 患者接受 ICD 治疗作为对照组（n = 87）。主要终点是 CRT 的超声心动图反应，定义为从基线到 1 年时左心室（LV）和左心房容积的百分比变化。次要终点是心力衰竭或死亡。非 LAFB 组与对照组相比，LV 舒张末期容积、LV 收缩末期容积和左心房容积的减少百分比显著更大（-11%，p <0.0001；-17%，p <0.0001；-15%，p <0.0001，分别）和 LAFB（-5%，p = 0.028；-7%，p = 0.019；-6%，p = 0.022；分别）。多元分析显示，LAFB（22%）、非 LAFB（21%）或 ICD 仅组（20%）在 3 年的死亡率或心力衰竭粗事件率之间无差异（p = NS）。结论：在 RBBB 患者中，传导模式影响 CRT 的超声心动图反应，无 LAFB 传导模式者 LV 和左心房容积降低有利。在 3 年的随访期间，这种超声心动图获益并未转化为心力衰竭或死亡的减少。
