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PubMed1976

[Ischemic lesions of the left branch of the bundle of His. Their relation of left hemiblock].

The term "hemiblock of the left branch of the bundle of His" seems to a histologist to be too precise to be accepted without reservation. Ten cases with septal infarction, with or without left intraventricular conduction problems, were studied by serial sectioning of the heart; these are used as a basis for a discussion of the concepts of electrocardiography, and its implications in the prognosis of patients with myocardial necrosis.

Bundle of His↗
PubMed1976

[Tachycardia-dependent paroxysmal block in the bundle of His. Electrophysiological demonstration].

The authors report the case of a patient who presented with angina of effort followed by transient loss of consciousness or syncope. Clinical examination yielded little information. The electrocardiogram showed signs of an old antero-septal infarct, and a slightly prolonged PR interval at 0.22 s. A recording of the activity of the bundle of His showed a double H potential, whose two components were separated by an interval of 80 ms. This interval increased progressively under the influence of atrial stimulation. At a critical frequency of 125/mn, a complete block below the bundle of His was produced; this only reverted after slowing or cessation of stimulation. The same phenomenon occurred at rates between 125/mn and 150/mn. By contrast stimulation at 170/mn was followed by a 2:1 block below the bundle of His. It is to be presumed that the complete A-V block was occasioned by latent conduction of the impulse in the injured area. If the rate was increased yet again, the level of the block became displaced to the upper limit of this area. The absence of latent conduction then allowed the abnormal fibres to recover. The present study thus demonstrates the existance of a special type of paroxysmal A-V block: a bundle block which is dependant upon tachycardia.

Aged↗
PubMed1976

["Habitual" left branch block alternating with 2 "disguised" bracnch block].

Two cases of alternating left bundle branch block and "masquerading block" (with left bundle branch morphology in the stnadard leads and right bundle branch block morphology in the precordial leads) were studied by serial tracings and his bundle electrocardiography. In case 1 "the masquerading" block was associated with a first degree AV block related to a prolongation of HV interval. This case is to our knowledge the first cas of alternating bundle branch block in which his bundle activity was recorded in man. In case 2, the patient had atrial fibrilation and His bundle recordings were performed while differents degrees of left bundle branch block were present: The mechanism of the alternation and the concept of "masquerading" block are discussed. It is suggested that this type of block represents a right bundle branch block associated with severe lesions of the "left system".

Aged↗
PubMed1977

Wolff-Parkinson-White syndrome type A obscured by left bundle branch block.

2 patients are presented whom the presence of left bundel branch block obscured the signs of the Wolff--Parkison--White syndrome expected with a bypass on the left side of the heart. While it was possible to infer the presence of both disorders from the surface ECGS, electrophysiological studies proved invaluable in defining the precise situation in both cases. When atypical electrocardiographic appearances are observed in the Wolff-Parkinson-White syndrome, careful investigation may reveal the cause to be bundle branch block on the same side of the hear as the anomalous pathway. In both patients there was in addition evidence of sinoatrial disease, which was associated with the occurrence of arrythmias, and this was also confirmed with intracardiac studies.

Adult↗
PubMed1977

Clinical judgement is not sufficient for the management of conduction defects (indications for diagnostic electrophysiologic studies).

Although analysis of the surface electrocardiograms is usually sufficient in the diagnosis and management of patients with cardiac arrhythmias, electrophysiologic studies can improve diagnostic, therapeutic, and prognostic decisions. Indications for electrophysiologic studies appear to include the following: (1) asymptomatic patients with chronic second degree AV block, both type I and type II with or without bundle branch block; (2) asymptomatic patients with complete AV block; (3) symptomatic patients with bundle branch block and 1:1 AV conduction; (4) patients with bundle branch block complicating acute myocardial infarction; (5) patients with electrocardiograms suggesting pseudo AV block; (6) symptomatic patients with sinus bradycardia, in whom the causal relationship is not clear enough to justify pacing therapy; (7) patients with frequent, troublesome paroxysmal supraventricular tachycardia; (8) patients with Wolff-Parkinson-White syndrome and frequent paroxysmal supraventricular tachycardia; (9) patients with recurrent paroxysmal ventricular tachycardia; (10) patients with syncope or severe dizziness in whom the causal mechanism is not defined.

Arrhythmia, Sinus↗
PubMed1977

Atypical 2nd degree AV block due to bilateral bundle branch block with Wenckebach phenomenon and concealed conduction in the bundle branch system.

A case of bilateral bundle branch block is described with the following features: -- 2nd degree infranodal AV block due to bilateral, intermittently synchronous "phase 3" bundle branch block; -- occasional AV conduction failure due to concealed His bundle extrasystoles; -- right bundle branch block pattern due to retrograde activation from the left bundle branch; -- QRS complexes having normal duration due to uniform slow conduction in both bundle branches; -- Wenckebach phenomenon in the right bundle branch; -- concealed conduction in both branches. The above interpretations are based on the use of His bundle recordings, results of right atrial stimulation and of pharmacological testing. Determinations of the lengths of all H--H intervals, whether H was followed by a ventricular response or blocked, permitted insight into the mechanism of 2nd degree AV block with varying (right and left) bundle branch block.

Aged↗
PubMed1977

Echo ICT.

Explore the source record for details and available documents.

Bundle-Branch Block↗
PubMed1979

[State of the heart conduction system in the sick sinus syndrome (according to the recording of the bundle of His potentials and the atrial stimulation test)].

It was established that the presence of Samoilov-Wenckebach's periods and prolongation of the H--V interval at low frequency of the imposed rhythm as well as periods of asystolia of more than 1,200 msec are most typical for these patients. An attempt was made to determine the type of cardiac stimulation indicated for such patients from the character of the disorders of rhythm observed in them and the initial frequency of their own cardiac contractions.

Action Potentials↗
PubMed1979

[Treatment of severe ventricular arrhythmia by means of repeated cardiac stimulation].

The overdrive pacing method is widely used now in clinical practice for prevention and treatment of severe ventricular disorders of the cardiac rhythm. The mechanisms of arrhythmia suppression by means of this stimulation is analysed. Indications are determined for the choice of the site of stimulation and optimal impulce frequency in ischemic heart disease, and overdosage with digitalis drugs, as well as in myocardiopathy.

Adult↗