Right and Left Ventricular Activation Sequence in Patients with Heart Failure and Right Bundle Branch Block:
A Detailed Analysis Using Three‐Dimensional Non‐Fluoroscopic Electroanatomic Mapping System

Abstract

Degree of LV activation delay is similar between HF patients with LBBB and RBBB. Moreover, patients with RBBB have larger right-sided conduction delay compared to patients with LBBB. The assessment of these electrical abnormalities is important to understand the rationale for delivering CRT in HF patients with RBBB.

Right Bundle Branch Block and Impaired Left Ventricular Function as Evidence of a Left Ventricular Conduction Delay

“…14 Furthermore, a recent study demonstrated that LV activation spreads slowly, from the septal or anterior breakthrough site, toward the apical and lateral regions, to the posterolateral basal region and around the mitral valve, which is the latest activated zone in HF patients with either RBBB or LBBB. 21 Thus, in CRBBB patients with advanced HF, LV activation is delayed as much as in the patients with isolated LBBB. In the present study, CRT was effective for the CRBBB patients with LV dyssynchrony.…”

“…Our results were almost identical to those obtained from a study using an electro-anatomical mapping system. 21 Therefore, we think that measurement using TDI and TTI is a useful and reliable tool for evaluating the ventricular synchrony.…”

“…[18][19][20] In contrast there is little data for patients who present with nonspecific conduction delays or RBBB. 21 Thus, the relationship of CRBBB to ventricular dyssynchrony and the predictors of CRT effectiveness in CRBBB patients have not been fully clarified.…”

“…In the patients with RBBB, a single RV breakthrough site appeared in the septum, and its activation slowly spread toward the anterior region and continued so that the latest activated regions were the right lateral wall and the outflow tract. 21 The mechanism of the RV activation sequence in RBBB patients is considered to be most likely a result of cell-to-cell conduction, from the septum to the anterior wall, to the lateral wall, and finally to the outflow tract. 21 That mechanism may be responsible for the differences in the TDRV-SEPT and TDRV-LAT between the CRBBB patients and control subjects in the present study.…”

“…21 The mechanism of the RV activation sequence in RBBB patients is considered to be most likely a result of cell-to-cell conduction, from the septum to the anterior wall, to the lateral wall, and finally to the outflow tract. 21 That mechanism may be responsible for the differences in the TDRV-SEPT and TDRV-LAT between the CRBBB patients and control subjects in the present study.…”