4:1 atrioventricular (AV) block.
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Atrial Flutter↗
Biomedical subjects
Takakazu Katoh
Publications and source records attributed to Takakazu Katoh.
Atrial escape-capture bigeminy in dominant atrial rhythm with 2:1 exit block.
A 27-year-old woman with atrial bigeminy is reported in whom long PP intervals alternate with short PP intervals. All P waves are negative in lead II and all PR intervals measure 0.12 s. In the 12-lead electrocardiogram, however, these P waves were definitely different in configuration from each other, and were divided into two groups. Namely, these negative P waves are divided into those of dominant atrial rhythm J1 with 2:1 exit block, and those of atrial escape J2. Long J1-J2 intervals alternate with short J2-J1 intervals. These electrocardiographic findings show the presence of atrial escape-capture bigeminy. Such atrial escape-capture bigeminy in dominant atrial rhythm with 2:1 exit block has never been reported before.
Adult↗
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.
Adolescent↗
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.
Aged↗
Alternating reversed wenckebach periodicity: Concealed electrotonic conduction as a possible mechanism.
Electrocardiograms were taken from a 67-year-old man with 2:1 atrioventricular block in whom alternating reversed Wenckebach periodicity was found. Long PR intervals of alternately conducted P waves progressively shortened until an alternate P wave was blocked. After an alternate P wave was blocked, the next alternate P wave was conducted to the ventricles with a markedly long PR interval. Then long PR intervals of alternately conducted P waves progressively shortened again until an alternate P wave was blocked. This is the first report on alternating reversed Wenckebach periodicity. It seems that concealed electrotonic conduction of alternately blocked impulses occurred as a possible mechanism.
Aged↗
Double ventricular response caused by longitudinal dissociation in the his bundle.
Electrocardiograms were taken from a 36-year-old woman with normal sinus rhythm in which 4 types of QRS complexes and 2 types of fusion QRS complexes were found in configuration. To interpret this arrhythmia, we proposed 3 unique mechanisms: a) double ventricular response through the fast pathway mainly directing to the right bundle branch and the slow pathway mainly directing to the left bundle branch, b) longitudinal dissociation in the His bundle, and c) transverse conduction in the lower edge of the dissociation. Although functional longitudinal dissociation in the atrioventricular node has been reported, longitudinal dissociation in the His bundle is a rare arrhythmia.
Adult↗
Apparent bradycardia-dependent advanced second-degree atrioventricular block.
A 65-year-old man with repeated chest discomfort and dizzy spells was transferred by an emergency car. On the way to hospital, his pulse was palpable as regular 4 to 5 beats followed by an unpalpable period of about 4 s. His electrocardiographic monitor showed that 4 to 5 sinus QRS complexes were followed by consecutive 3 to 4 blocked sinus P waves, which occurred repeatedly. When PP intervals gradually shortened during inspiration, sinus impulses were conducted to the ventricles, whereas when PP intervals lengthened during expiration, 3 to 4 sinus impulses were blocked in succession. An attempt was made to explain the mechanism for such apparent bradycardia-dependent atrioventricular block by using the concepts of periodic increases in vagal tone due to respiration and concealed electrotonic conduction of blocked impulses. Such a peculiar form of advanced second-degree atrioventricular block has never been reported before.
Aged↗
"Sinus node" reentrant tachycardia associated with respiration.
A 77-year-old woman (case 1) and a 57-year-old woman (case 2) with paroxysmal "sinus tachycardia" are reported in whom the tachycardia repeatedly occurred associated with respiration. In both cases, reentrant P' waves are almost the same in configuration as sinus P waves, and P'R intervals are also the same in length as PR intervals. In case 1, the tachycardia was initiated during inspiration, and was terminated during expiration; showing tachycardia-dependent initiation. On the contrary, in case 2, the tachycardia was initiated during expiration, and was terminated during inspiration; showing apparent bradycardia-dependent initiation. Although exact diagnosis was not made by electrophysiologic studies, attempts were made to explain the mechanism of such unique tachyarrhythmias associated with respiration by using the concept of sinus node reentrant tachycardia as a possible mechanism.
Adrenergic beta-1 Receptor Antagonists↗