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Journal ArticleDOI

Analysis of the A-V Conduction Defect in Complete Heart Block Utilizing His Bundle Electrograms

01 Mar 1970-Circulation (Lippincott Williams & Wilkins)-Vol. 41, Iss: 3, pp 437-448
TL;DR: Bilateral bundle-branch block was probably the mechanism of block in the majority of the patients with CHB; this emphasizes the clinical significance of ECG patterns indicating bilateral bundle- Branch block during normal sinus rhythm with 1:1 A-V conduction.
Abstract: Twenty-one patients with complete heart block (CHB) were studied by recording His bundle (BH) electrograms. The site of block was localized proximal or distal to the site at which the BH electrogram was recorded. Eighteen patients had block distal to the recorded BH deflection. One of these 18 patients had a narrow QRS complex indicating block within the His bundle; the other 17 had wide QRS complexes probably due to bilateral bundle-branch block. The three patients with block proximal to the His bundle are examples of A-V nodal block or block in the uppermost portion of the BH. Two of these three had normal QRS complexes; the third with a left bundle-branch block pattern demonstrated that during CHB the ECG criteria for the localization of the site of block are not dependable. The conduction time from the atrium to the BH (A-H time) was measured in the 18 patients with CHB distal to the BH and was within the normal range. With atrial pacing there was progressive lengthening of the A-H time, and Wenckebac...
Citations
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Journal ArticleDOI
TL;DR: His bundle recordings during spontaneous and induced episodes of paroxysmal supraventricular tachycardia (SVT) demonstrated that the site of reentry responsible for this arrhythmia was in the A-V node.
Abstract: His bundle recordings during spontaneous and induced episodes of paroxysmal supraventricular tachycardia (SVT) demonstrated that the site of reentry responsible for this arrhythmia was in the A-V node. In five patients studied, A-V conduction time and refractory periods were normal, but atrial premature depolarizations (APD) within a portion of the relative refractory period of the A-V node consistently produced atrial reentry—echoes or sustained SVT. In two patients, APDs falling within the A-V effective refractory period failed to excite the His bundle but still reentered within the A-V node and began SVT. It was noted that the various relationships between atrial and ventricular depolarizations on the surface ECG did not reflect different mechanisms for SVT, but only variations in A-V nodal conduction time.

224 citations

Journal ArticleDOI
TL;DR: It is demonstrated that the electrocardiographic manifestations of all three degrees of A-V block can result from conduction abnormalities present in either of these three regions, viz, A- V node, BH and the His-Purkinje system.

223 citations

Journal ArticleDOI
TL;DR: The data support the clinical observations that Mobitz II A-V blocks are associated with bilateral bundle-branch block as well as with BH lesions and demonstration of the Wenckebach cycles within the HPS (BH or either bundle branch), which cannot be determined from the surface ECG, has important clinical implications.
Abstract: Fourteen patients with conduction defects were analyzed by using bundle of His (BH) recordings. The BH electrograms were validated by BH and right atrial pacing (AP). In 12 patients with Mobitz type II A-V block, failure in impulse transmission for the dropped beats was localized distal to the recording site of the BH. Three of these 12 patients showed normal QRS complexes. In two of these three, the QRS complexes remained unchanged during intermittent periods of complete heart block (CHB), and thus represent His bundle rhythm with subsidiary pacemaker arising above the bifurcation of the BH. The A-H time in this group of 12 patients ranged from 60 to 160 msec and the H-V time ranged from 40 to 90 msec. At any atrial rate (NSR or AP) conduction time through the A-V node (A-H), and His-Purkinje system (H-V) remained constant. With increasing atrial (A) rates during AP, the number of impulses blocked distal to the BH increased. At high AP rates Wenckebach phenomenon between A and BH occurred concomitantly w...

206 citations

Journal ArticleDOI
01 Jul 1973-Chest
TL;DR: His bundle electrograms (H) were recorded in 61 patients without evidence of conduction disease on the surface electrocardiogram, in order to establish the normal range ofConduction intervals, which will be of use in assessing patients with suspected cardiac conduction Disease.

147 citations

References
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Journal ArticleDOI
TL;DR: In patients with first degree heart block during sinus rhythm the A-H time was prolonged and the H-V time was either normal or prolonged, and in higher degrees of heart block, the block was localized either in the proximal or distal A-V junction.
Abstract: His bundle electrograms were recorded in 20 patients. Conduction times from atrium to His bundle (A-H time) and His bundle to ventricle (H-V time) were measured and the sites of delay or block were localized to the proximal or distal A-V junction. On progressively increasing the atrial rate by atrial pacing, the A-H time lengthened, while the H-V time remained constant. Premature atrial beats usually resulted in prolongation of the A-H time only. In some instances, premature atrial beats also resulted in prolongation of the H-V time and aberrant ventricular conduction (change in configuration of the QRS complex). In patients with first degree heart block during sinus rhythm the A-H time was prolonged and the H-V time was either normal or prolonged. In higher degrees of heart block, the block was localized either in the proximal or distal A-V junction.

160 citations

Journal ArticleDOI
TL;DR: Several types of atypical right bundle branch block patterns described by the author earlier now appear to be caused by a combination of block of the entireright bundle branch and a part of the left branch.

143 citations

Journal ArticleDOI
TL;DR: Bundle of His pacing was used to establish a His bundle rhythm in a patient with complete heart block localized within the His bundle, and the retrograde Wenckebach phenomenon was demonstrated.
Abstract: His bundle electrograms were recorded and A-V junction pacing was achieved in 30 patients by a pervenous electrode catheter technic. His bundle pacing was achieved in 26, and A-V node pacing in five patients. Conduction time from atrium to the His bundle (A-H time) and His bundle to ventricular activation (H-V time) were measured. During His bundle pacing, the pacing impulse to ventricular activation time (PI-R) was the same as the H-V time during normal sinus rhythm and remained constant at different pacing rates. With A-V node pacing, the PI-R interval was shorter than the conduction time from atrium to the ventricle (sum of the A-H and the H-V time) but longer than the H-V time, and there was progressive lengthening of PI-R interval, with increase in pacing rates. The QRS complex remained unchanged in all ECG leads with BH and A-V node pacing from that during normal sinus rhythm. During BH pacing, the retrograde Wenckebach phenomenon was demonstrated. Bundle of His pacing was used to establish a His bundle rhythm in a patient with complete heart block localized within the His bundle. BH pacing is of value for validation of His bundle electrograms and differentiation from that of right bundle branch. Clinically, this technic has proved extremely useful in definitive diagnosis of bilateral bundle-branch block in patients with right bundle-branch block and left axis deviation and infarction.

143 citations