Histopathological examination of concept of left hemiblock.

Demoulin, J. C.; Kulbertus, H

doi:10.1136/hrt.34.8.807

Cited by 211 publications

(77 citation statements)

References 17 publications

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“…In 20 of the 32 hearts a portion of the His bundle traveled within the inferior margin of the membranous septum and then along the subjacent left side of the crest of the muscular IV septum (figs. [3][4][5]. In these hearts the LBB origin varied markedly in total width from 2 to 14 mm; the LBB regularly originated from the His bundle at the left septal endocardium.…”

Section: Methodsmentioning

confidence: 99%

Anatomical configuration of the His bundle and bundle branches in the human heart.

Massing¹,

James²

1976

Circulation

262

110

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The relationships among the His bundle, the origin of both bundle branches, and the interventricular (IV) septum were examined histologically in 32 human hearts, and the entire bundle branch systems were delineated in 13 of these. The His bundle in five hearts traversed the right IV septal crest, and the LBB origin was a very narrow stem (maximum 1.5 mm in cross-section) crossing from right to left through the inferior margin of the membranous septum. Proximal LBB anatomy was extremely variable, demonstrating multiple fiber groups which fanned out over the entire left septal surface. The LBB did not divide into two discrete divisions without multiple interconnections. The RBB formed an obtuse angle with the His bundle in 27 of 32 hearts. In those five hearts with "right-sided His bundles," the right bundle branch was a direct continuation. The clinical, electrophysiologic, and electrocardiographic implications of these anatomical observations are discussed.

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Section: Methodsmentioning

confidence: 99%

Anatomical configuration of the His bundle and bundle branches in the human heart.

Massing¹,

James²

1976

Circulation

262

110

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“…In 1972, Demoulin et al reported their histopathological findings in human patients without known cardiac disease, showing that the LBB emerges from the His bundle between the non-coronary and right-coronary aortic cusps and runs as a 6-10-mm wide ribbon-like structure inferiorly and slightly anteriorly over the septal subendocardium. 5 With considerable variation, the fibers of the LBB quickly separate to form fasciculi in anterior, posterior and often septal main radiations (Figure 1). The LBB enables fast activation of the left ventricle (LV) because it ends in a rich peripheral Purkinje network that couples with individual (sub)endocardial myocardial cells.…”

Section: Lbbbmentioning

confidence: 99%

Cardiac Resynchronization Therapy - Refocus on the Electrical Substrate -

Strik

Ploux

Vernooy

et al. 2011

Circ J

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Circulation Journal Official Journal of the Japanese Circulation Society http://www. j-circ.or.jp s its name suggests, cardiac resynchronization therapy (CRT) aims to treat the electrical substrate in symptomatic heart failure (HF) patients with reduced LV ejection fraction (EF) and wide QRS complex. A recent metaanalysis pooled more than 3,000 CRT patients from 6 trials and reported a reduction in all-cause mortality of 29% and a reduction in the number of new hospitalizations for worsening HF of 37%. 1 Nevertheless, a QRS duration >120 ms has proven to be a moderate predictor of CRT efficacy, as 30-50% of implanted patients do not respond to the therapy. This has sparked major efforts into identifying patients who benefit from CRT by investigating mechanical dyssynchrony. However, the relatively slow improvement in CRT efficacy in recent years has renewed interest in the electrical substrate. It has become increasingly clear that left bundle branch block (LBBB) is the hallmark conduction disease that is treatable by CRT, as evidenced by efficacy of CRT in canine hearts with isolated LBBB and in CRT patients with LBBB compared to CRT patients with other conduction disorders. 2, 3 In this review we will explore current knowledge concerning the electrical substrate in CRT candidates and apply this to current CRT practice. We will then discuss why the electrical substrate is both essential and sufficient for successful CRT. We will show that this is true if the electrical substrate is defined more accurately than just by duration of the QRS complex. LBBBA century has passed since Eppinger and Tothberger first described LBBB by associating distinctive electrophysiological changes with the destruction of only a small region in the interventricular septum in the canine heart. 4 The typical QRSmorphology changes seen in the esophageal-to-rectal lead in the dogs were directly extrapolated to leads II and III in human patients. This misinterpretation caused LBBB to be erroneously diagnosed as right bundle branch block (RBBB) and vice versa in the first quarter of the past century.It was only until decades after the rectification that the anatomy of the left bundle branch (LBB) and the significance of its dysfunction were investigated in detail. In 1972, Demoulin et al reported their histopathological findings in human patients without known cardiac disease, showing that the LBB emerges from the His bundle between the non-coronary and right-coronary aortic cusps and runs as a 6-10-mm wide ribbon-like structure inferiorly and slightly anteriorly over the septal subendocardium. 5 With considerable variation, the fibers of the LBB quickly separate to form fasciculi in anterior, posterior and often septal main radiations (Figure 1). The LBB enables fast activation of the left ventricle (LV) because it ends in a rich peripheral Purkinje network that couples with individual (sub)endocardial myocardial cells. 6 Extensive electrical mapping in isolated human hearts with an intact LBB showed up to 3 LV endocardial breakthrough si...

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“…It is the opinion of the panel that, in the presence of a SNRT >2 s or CSNRT >1 s, sinus node dysfunction may be the cause of syncope. [170] , is still the most clinically useful, albeit being a simplification [171,172] . Also patients with bifascicular block (right bundle branch block plus left anterior or left posterior fascicular block, or left bundle branch block) are at higher risk of developing highdegree AV block.…”

Section: Task Force Report 1273mentioning

confidence: 99%