Intra-His bundle block: clinical, electrocardiographic, and electrophysiologic characteristics

Andréa, Eduardo Machado; Atié, Jacob; Maciel, Washington; Oliveira, Nilson Araújo de; Camanho, Luiz Eduardo Montenegro; Belo, Luís Gustavo; Carvalho, Hecio; Siqueira, Leonardo; Saad, Eduardo; Venâncio, Ana Cláudia

doi:10.1590/s0066-782x2002001400010

Cited by 5 publications

(4 citation statements)

References 23 publications

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“…[ 7 ] Moreover, in patients with symptomatic second-degree AV block investigated by the electrophysiologic study, 25% of patients exhibited the intra-His Wenckebach phenomenon. [ 8 ] Such evidence partly explained the Wenckebach phenomenon induced by severe MB with the hindrance of blood supply to the subnodal system in our patient.…”

Section: Discussionsupporting

confidence: 54%

Severe myocardial bridge presenting as paroxysmal atrioventricular block

Lin

Lai

Wang

et al. 2021

Journal of Postgraduate Medicine

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Chest pain complicated with electrocardiographic changes is not an uncommon scenario in emergency departments, which should be examined cautiously. We describe a 51-years-old man with a myocardial bridge of coronary artery presenting with simultaneous Mobitz type I atrioventricular block on electrocardiography. Echocardiography excluded valvular abnormality and systolic/diastolic dysfunction. Coronary angiography confirmed the diagnosis of a myocardial bridge at the middle segment of the left anterior descending artery, involving the most dominant septal perforator branch with marked systolic compression. The patient underwent coronary artery bypass grafting surgery and was followed up uneventfully at the outpatient department with medical treatment of diltiazem and clopidogrel. The present case is being reported to highlight that clinicians should be alert to such a congenital abnormality as a potential cause of repeated myocardial infarction and conduction abnormality.

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Section: Discussionsupporting

confidence: 54%

Severe myocardial bridge presenting as paroxysmal atrioventricular block

Lin

Lai

Wang

et al. 2021

Journal of Postgraduate Medicine

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“…Split His: Recording two components in the His electrogram (H1 and H2) characterizing fragmentation of the His potential with a duration longer than 25–30 ms 10 (Figure 1 ).…”

Section: Methodsmentioning

confidence: 99%

Electrophysiological study as a predictor of mortality in unexplained syncope

Pinos

Lima

Sant’Anna³

et al. 2023

Journal of Arrhythmia

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Background: Electrophysiological study can help in the diagnosis of arrhythmic syncope. According to the electrophysiological study finding, the prognosis of patients with syncope is still a matter of study. Objective:The aim of this study was to assess the survival of patients undergoing electrophysiological study according to their findings and to identify clinical and electrophysiological independent predictors of all-cause mortality.Methods: A retrospective cohort study included patients with syncope who underwent electrophysiological study from 2009 to 2018. A Cox logistic regression analysis was performed to identify independent prognostic factors for all-cause mortality. Results:We included 383 patients in our study. During a mean follow-up of 59 months, 84 (21.9%) patients died. The split His group had the worst survival compared with the control group, followed by sustained ventricular tachycardia and HV interval ≥ 70 ms, respectively (p = .001; p < .001; p = .03). The supraventricular tachycardia group showed no differences compared with the control group (p = .87). In the multivariate analysis, independent predictors of all-cause mortality were Age (OR 1.06; 1.03-1.07; p < .001); congestive heart failure (OR 1.82; 1.05-3.15; p = .033); split His (OR 3.7;; p = .016); and sustained ventricular tachycardia (OR 1.84; 1.02-3.32; p = .04). Conclusion:Split His, sustained ventricular tachycardia, and HV interval ≥ 70 ms groups had worse survivals when compared to the control group. Age, congestive heart failure, split His, and sustained ventricular tachycardia were independent predictors for all-cause mortality.

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“…Patients with underlying chronic LBBB during sinus rhythm who develop intra-His block 22–24 may actually develop a narrower (near-normal) QRS complex during complete atrioventricular block with His-escape rhythm (Figure 4). Sudden normalization of QRS morphology, taking place during complete atrioventricular block, inevitably generates cardiac memory.…”

Section: Arrhythmogenic Cardiac Memory In Bradyarrhythmia-induced Lon...mentioning

confidence: 99%

“…This sequence of events suggests that the underlying cause of ventricular fibrillation was torsades de pointes caused by cardiac memory during a sudden change in the morphology of the escape rhythm during atrioventricular block. 10 Patients with underlying chronic LBBB during sinus rhythm who develop intra-His block [22][23][24] may actually develop a narrower (near-normal) QRS complex during complete atrioventricular block with Hisescape rhythm (Figure 4). Sudden normalization of QRS morphology, taking place during complete atrioventricular block, inevitably generates cardiac memory.…”

Section: Arrhythmogenic Cardiac Memory In Bradyarrhythmia-induced Lon...mentioning

confidence: 99%

Arrhythmogenic Effects of Cardiac Memory

et al. 2022

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Cardiac memory is the term used to describe an interesting electrocardiographic phenomenon. Whenever a QRS complex is wide and abnormal, such as during ventricular pacing, the T waves will also be abnormal and will point to the opposite direction of the wide QRS. If the QRS then normalizes, such as after cessation of ventricular pacing, the T waves will normalize as well, but at a later stage. The period of cardiac memory is the phase between the sudden normalization of the QRS and the eventual and gradual return of the T waves to their baseline morphology. Cardiac memory is assumed to be an innocent electrocardiographic curiosity. However, during cardiac memory, reduction of repolarizing potassium currents increases left ventricular repolarization gradients. Therefore, when cardiac memory occurs in patients who already have a prolonged QT interval (for whatever reason), it can lead to a frank long QT syndrome with QT-related ventricular arrhythmias (torsades de pointes). These arrhythmogenic effects of cardiac memory are not generally appreciated and are reviewed here for the first time.

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Intra-His bundle block: clinical, electrocardiographic, and electrophysiologic characteristics

Abstract: Objective -To assess the clinical, electrocardiographic, and electrophysiologic characteristics of patients (pt) with intra-His bundle block undergoing an electrophysiologic study (EPS). Methods -

Cited by 5 publications

References 23 publications

Severe myocardial bridge presenting as paroxysmal atrioventricular block

Severe myocardial bridge presenting as paroxysmal atrioventricular block

Electrophysiological study as a predictor of mortality in unexplained syncope

Arrhythmogenic Effects of Cardiac Memory

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