Prominent anterior QRS force as a manifestation of left septal fascicular block

Nakaya, Yutaka; Hiasa, Yoshikazu; Murayama, Yoshiki; Ueda, Seito; Nagao, Takashi; Niki, Toshiyuki; Mori, Hiromu; Takashima, Yasuji

doi:10.1016/s0022-0736(78)80028-4

Cited by 30 publications

(6 citation statements)

References 14 publications

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“…4 -7 In fact, the existence of midseptal fibers cannot be disregarded, and as such the functional and, probably, clinical significance of a middle or septal fascicle cannot be totally ignored either. [7][8][9] In accordance with our studies on the anatomy of the LBB, the midseptal fibers are given off in most cases by the posterior division, less frequently by the anterior division or from both, and in few cases have an independent origin from the central part of the main LBB at the site of its bifurcation. 1,2 Figure 1 shows the LBB and its divisions from human hearts, obtained by macroscopic dissection and by reconstruction of the anatomy from serial histological sections of the left septal myocardium.…”

Section: Anatomy Of the Lbb: The Middle Or Septal Fasciclesupporting

confidence: 85%

Hemiblocks Revisited

2007

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Abstract-The trifascicular nature of the intraventricular conduction system and the concept of trifascicular block and hemiblock were described by Rosenbaum and his coworkers in 1968. Since then, anatomic, pathological, electrophysiological, and clinical studies have confirmed the original description and scarce advances have been developed on the subject. In the present study, we attempt to review and redefine reliable criteria for the electrocardiographic and vectorcardiographic diagnosis of left anterior and posterior hemiblock. One of the most important problems related to hemiblocks is that they may simulate or conceal the electrocardiographic signs of myocardial infarction or myocardial ischemia and may mask or simulate ventricular hypertrophy. Illustrative examples of these associations are shown to help the interpretation of electrocardiograms. The incidence and prevalence of the hemiblocks is presented based on studies performed in hospital patients and general populations. One of the most common causes of hemiblocks is coronary artery disease, and there is a particularly frequent association between anteroseptal myocardial infarction and left anterior hemiblock. The second most important cause is arterial hypertension, followed by cardiomyopathies and Lev and Lenègre diseases. The hemiblocks may also occur in aortic heart disease and congenital cardiopathies. Left anterior hemiblock is more common in men and increases in frequency with advancing age. Evidence is presented regarding the relationship of spontaneous closure of ventricular septal defects, which may explain the finding of this and other conduction defects in young populations. Isolated left anterior hemiblock is a relatively frequent finding in subjects devoid of evidence of structural heart disease. Conversely, isolated left posterior hemiblock is a very rare finding; its prognostic significance is unknown and is commonly associated with right bundle-branch block. The most remarkable feature of this association is that the prognosis is much more serious with a great propensity to develop complete atrioventricular block and Adams-Stoke seizures. Key Words: epidemiology Ⅲ heart septal defects Ⅲ myocardial infarction Ⅲ heart block Ⅲ bundle-branch block T hirty-eight years have elapsed since Rosenbaum et al published their seminal work that put together diverse previous observations and brought about a rational and complete analytic approach to the trifascicular concept of intraventricular conduction.These conclusive studies and an exhaustive review of the preceding knowledge of the subject were first published in the Spanish monograph, 1 and later a shorter updated version was presented to acquaint the English reader with the electrocardiographic manifestations and clinical correlation of the abnormal spread of ventricular excitation. 2 A series of articles published by the same authors between 1969 and 1973 also contributed to the expansion of the recognition of this research work. As stated by Herman N. Uhley, 3 this work triggered and infl...

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Section: Anatomy Of the Lbb: The Middle Or Septal Fasciclesupporting

confidence: 85%

Hemiblocks Revisited

2007

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“…The most plausible explanation for RBBB-associated anteroseptal Q wave formation is that septal (median) fascicular block (SFB) might be concomitantly involved in the genesis of this ECG phenomenon [28, 29, 30, 31]. However, the precise mechanism by which SFB may contribute to a false-positive diagnosis of Q wave MI, particularly in the presence of RBBB, has not been identified.…”

Section: Impact Of the Level Of Rbbb On Transseptal Conduction And Itmentioning

confidence: 99%

“…However, the precise mechanism by which SFB may contribute to a false-positive diagnosis of Q wave MI, particularly in the presence of RBBB, has not been identified. Consensus on ECG criteria for the SFB is also lacking: some investigators have attributed SFB to the apparent loss of anterior forces resulting in development of transient Q waves in leads V 1 –V 2 [10, 28, 29, 32], while others have linked SFB with the apparent increase of anterior forces in the horizontal but not the frontal plane (a tall initial R wave in the right chest leads without a change in QRS axis) [31, 33]. Still others [34, 35, 36]believe that this conduction block, depending on the site of insertion of the septal, anterior, and posterior fascicles, could produce an apparent loss or gain of anterior forces.…”

Section: Impact Of the Level Of Rbbb On Transseptal Conduction And Itmentioning

confidence: 99%

False-Negative and False-Positive ECG Diagnoses of Q Wave Myocardial Infarction in the Presence of Right Bundle-Branch Block

Gussak

Wright²,

Bjerregaard

et al. 2000

Cardiology

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Right bundle-branch block (RBBB) has not traditionally been seen as an obstacle to ECG diagnosis of Q wave myocardial infarction (MI) – in clinical electrocardiography and vectorcardiography – because this conduction disturbance is not believed to cause significant alterations in the spatial orientation of initial excitation wavefronts. In the era of large-scale clinical trials, however, where serial ECG analysis is among the major diagnostic tools in MI classification, both false-positive and false-negative diagnoses of MI in the presence of RBBB have become increasingly evident. Because of the limited detectability of Q wave MI by ECG in the presence of RBBB, the electrocardiographic finding of Q wave MI should not be regarded as an independent diagnostic tool. It is best to utilize independent corroboration to establish the diagnosis of transmural infarction when RBBB is present. Further investigations are warranted to better delineate sensitivity, specificity, and predictive value of Q wave MI in the presence of RBBB.

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“…The term left septal fascicular block is not recommended because of the lack of universally accepted criteria in AHA/ACCF/HRS guideline . There are various reports about the electrocardiographic presentations of left septal fascicular block, and they mainly fall to two categories: (1) Initial QRS vector directed to the left, loss or attenuation of initial r wave in right precordial leads accompanied by loss of septal q wave, (2) The prolongation of depolarization of left septal ventricle induces the prominent anterior QRS force, a striking R wave would manifest in the right precordial leads concurrently. The causes of the discrepancies between two categories may relate to the anatomical variations of left septal fascicular branch and the individual variability of anatomical location of interventricular septum.…”

Section: Discussionmentioning

confidence: 99%

A Case Report of Different Degrees of the Left Anterior, Septal and Posterior Fascicular Branch Block

Sun

Hong

Jin

2014

Noninvasive Electrocardiol

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We present a rare case of various conduction defects involving the left anterior, septal, and posterior branch in one patient. The different degrees of block of anterior, septal, and posterior fascicular of the left bundle branch indicate pathological changes in left ventricle. However, the values of this electrocardiographic presentation indicating the left ventricular function still need more investigations.

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Prominent anterior QRS force as a manifestation of left septal fascicular block

Cited by 30 publications

References 14 publications

Hemiblocks Revisited

Hemiblocks Revisited

False-Negative and False-Positive ECG Diagnoses of Q Wave Myocardial Infarction in the Presence of Right Bundle-Branch Block

A Case Report of Different Degrees of the Left Anterior, Septal and Posterior Fascicular Branch Block

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