Heart and Vascular Institute, University of Pittsburgh, Pittsburgh, PA, USA.
J Cardiovasc Transl Res. 2013 Jun;6(3):425-9. doi: 10.1007/s12265-013-9457-0. Epub 2013 Mar 19.
Electrocardiographic left bundle branch block (LBBB) may be due to intrinsic disease of the left bundle branch or induced by right ventricular apical (RVA) pacing. Prior reports clearly delineate the derogatory impact of LBBB on left ventricular (LV) mechanical function but suggest equivalent impact between varieties. We hypothesized that their effects were disparate and performed a within-patient comparison to test this notion. Patients (n = 20) with heart failure, intrinsic LBBB, and an implanted pacing device with right atrial and RVA leads were studied. Each patient underwent transthoracic three-dimensional speckle-tracking echocardiography during atrial pacing (intrinsic LBBB) and short atrioventricular delay atrial-RVA pacing, and these studies were compared. Relative to intrinsic LBBB, RVA pacing-induced LBBB produced greater intra-LV and interventricular dyssynchrony, a deterioration in LV function, and a shift in the site of latest activation. In patients with heart failure and LBBB, acute RVA pacing induces greater mechanical dyssynchrony and further impairs LV function.
心电图左束支传导阻滞（LBBB）可能是由于左束支的固有疾病或右心室心尖部（RVA）起搏引起的。先前的报告明确说明了 LBBB 对左心室（LV）机械功能的不良影响，但表明不同类型的影响相当。我们假设它们的影响是不同的，并进行了患者内比较来验证这一观点。研究了 20 例心力衰竭、固有 LBBB 和植入具有右心房和 RVA 导联的起搏装置的患者。每位患者均在心房起搏（固有 LBBB）和短房室延迟心房-RVA 起搏期间接受经胸三维斑点追踪超声心动图检查，并对这些研究进行了比较。与固有 LBBB 相比，RVA 起搏诱导的 LBBB 导致更大的 LV 内和室间不同步，LV 功能恶化，以及最晚激活部位的转移。在心力衰竭和 LBBB 的患者中，急性 RVA 起搏会引起更大的机械不同步，并进一步损害 LV 功能。
