Cases reported "Bundle-Branch Block"

Filter by keywords:



Filtering documents. Please wait...

1/3. Atypical atrioventricular Wenckebach periodicity caused by conduction through triple atrioventricular junctional pathway as a probable mechanism.

    Electrocardiograms were taken from an 84-year-old man with right bundle branch block in whom atypical atrioventricular Wenckebach periodicity was frequently occurred. The electrocardiographic findings as mentioned below suggested that the atypical periodicity was caused by conduction through triple atrioventricular junctional pathways as a probable mechanism. When a P wave was blocked after a markedly prolonged PR interval of 0.64 s, the RP interval containing this blocked P wave ranged between 0.84 s and 0.86 s, and the next P wave was followed by a QRS complex of the same configuration, with the PR interval of 0.35 s. On the other hand, when a P wave was blocked after a PR interval of 0.49 s or 0.52 s, the RP interval containing this blocked P wave was comparatively long, ie, 0.95 s or 0.98 s, and the next P wave was followed by a QRS complex of somewhat different configuration showing borderline left axis deviation, with a shorter PR interval of 0.21 s or 0.23 s. These findings suggest that longitudinal dissociation occurred not only in the atrioventricular junction but also in the His bundle. This is the first report suggesting triple atrioventricular junctional pathways probably associated with longitudinal dissociation in the His bundle.
- - - - - - - - - -
ranking = 1
keywords = periodicity
(Clic here for more details about this article)

2/3. Apparent bradycardia-dependent right bundle branch block associated with atypical atrioventricular Wenckebach periodicity as a possible mechanism.

    The Holter monitor electrocardiogram was taken from a 15-year-old male athlete. Intermittent right bundle branch block frequently occurred at rest. When sinus cycles gradually lengthened, sinus impulses were conducted to the ventricles with right bundle branch block (RBBB) in succession. When, thereafter, sinus cycles gradually shortened, sinus impulses were conducted without RBBB. However, it seems that these findings do not show true bradycardia-dependent RBBB. Atypical atrioventricular Wenckebach periodicity was occasionally found in which sudden shift from the period of comparatively short PR intervals to the period of long PR intervals occurred. In the Wenckebach periodicity, when a QRS complex occurs after a much longer pause, RBBB was not found, while when it occurs after a much shorter period, RBBB was found. This suggests that this case may be apparent bradycardia-dependent RBBB, namely, a form of tachycardia-dependent RBBB. This is the first report suggesting apparent bradycardia-dependent bundle branch block associated with gradual lengthening of sinus cycles, as a possible mechanism.
- - - - - - - - - -
ranking = 1
keywords = periodicity
(Clic here for more details about this article)

3/3. Atrioventricular alternating Wenckebach periodicity: conduction patterns in multilevel block.

    Atrioventricular (A-V) conduction patterns were analyzed in three patients with atrial pacing-induced alternating Wenckebach periodicity. These cases were unique because in each (1) separate levels of block responsible for the conduction disturbance were located above and below the His bundle recording site, and (2) there were several departures from the simple alternating Wenckebach pattern. Apparent supernormal conduction, temporary 1:1 conduction and a specific form of gap in A-V conduction resulted from the interplay of many factors including a simple mathematic relation of the blocking ratio at the two levels, the characteristics of the Wenckebach cycles, and the cycle length-dependent features of refractory periods at the different sites. The findings indicate that (1) delay in proximal impulse transmission is usually the critical factor in overcoming prolonged distal refractoriness and producing variable conduction atterns during the course of alternating Wenckebach periodicity; (2) many irregularities in alternating Wenckebach periodicity can be explained by known electrophysiologic mechanisms; and (3) simple mathematic equations alone are too rigid to reflect properly the dynamic process underlying this conduction disturbance.
- - - - - - - - - -
ranking = 1.1666666666667
keywords = periodicity
(Clic here for more details about this article)


Leave a message about 'Bundle-Branch Block'


We do not evaluate or guarantee the accuracy of any content in this site. Click here for the full disclaimer.