Endocardial activation of left bundle branch block.

Abstract

Endocardial catheter mapping was performed in 18 patients with left bundle branch block (LBBB). Four patients had no organic heart disease (group I), six had cardiomyopathy (group LI), and eight had coronary artery disease and previous infarction (group III). Twelve patients had one septal site of left ventricular endocardial breakthrough, while six had two left ventricular endocardial breakthrough sites, with one site always being septal. There was no significant difference among the groups with respect to time of left ventricular breakthrough (group I, 44 msec after the onset of the QRS complex; group II, 58 msec; and group III, 51 msec). Total left ventricular endocardial activation time was significantly longer in group 111 (1 19 msec) than group 1 (81 msec; p < .05) and group 11 (61 msec; p < .001). Duration of total right ventricular endocardial activation was 36 msec (seven patients). The final site of right ventricular activation was at 44 msec after the onset of the QRS complex. We conclude that (1) right ventricular activation occurs before initiation of left ventricular activation in patients with LBBB, (2) left ventricular endocardial activation in patients with LBBB most likely occurs as a result of right-to-left transseptal activation, (3) left ventricular endocardial activation sequence in patients with LBBB is heterogenous, and (4) patients with coronary artery disease and LBBB have significantly longer total left ventricular endocardial activation times than patients with no organic heart disease or those with cardiomyopathies. Circulation 69, No. 5, 914-923, 1984. OUR PRESENT UNDERSTANDING of ventricular activation in man is based on data derived from studies involving preparations in vitro and canine preparations and from intraoperative epicardial mapping of the human heart in a small number of patients. standing of ventricular activation in the human heart with left bundle branch block (LBBB) in vivo is therefore limited by several factors. These include differences between the anatomic and functional properties

Automatic Global and Regional Phase Analysis from Gated Myocardial Perfusion SPECT Imaging: Application to the Characterization of Ventricular Contraction in Patients with Left Bundle Branch Block

“…To validate the dyssynergy measurements, we chose patients with LBBB. In these patients, mechanical contraction of the LV had been shown to occur earlier in the cardiac cycle at the septal wall and later in other regions of the myocardium because the slower electrical impulse propagation through the conduction system caused increasingly delayed activation, with the latest activation site most often located in the inferior or lateral wall (32). Consequently, increased values for the dyssynchrony measurements should be more prevalent in the LBBB group, and regional measures should demonstrate a clear pattern of propagation of mechanical contraction from the septal to the lateral wall.…”

Cardiac Resynchronization Therapy - Refocus on the Electrical Substrate -

“…8 The heterogeneous activation patterns could be the result of (1) the varying anatomy of the LBB as shown in Figure 1, (2) variability in the location of LBB disease, being either proximal or distal or (3) the fact that cellular uncoupling as a consequence of LV hypertrophy can give rise to a LBBB-like QRS complex. Surprisingly, there is very little information about the nature of LBBB or about the eliciting factors (other than myocardial infarction).…”

Results of the randomized studies on cardiac resynchronization therapy and the reevaluation of the cardiac ventricular activation in left bundle branch block

“…Vassallo és mtsai [17] 1984-ben 18, BTSzB-ben szenvedő betegben endocardialis potenciáltérképeket rögzítettek és a kamrai aktiváció időpontjait izochron vonalakkal ábrázolták. A QRS szélessége betegeikben átlagosan 158 ms volt, tehát a valós BTSzB-kritériumoknak megfeleltek.…”