Types and clinical significance of fascicular blocks.
Explore the source record for details and available documents.
Bundle-Branch Block↗
SEARCH · PubMed Health
Results for “Bundle-Branch Block”
Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
[Paroxysmal tachycardia due to a latent Wolff-Parkinson-White syndrome].
The authors studied 35 cases of Bouveret type paroxysmal tachycardia with normal baseline ECB, without any signs of Wolff-Parkinson-White syndrome. In more than half the patients, it seems that it may be stated that the paroxysmal tachycardia is related not to a reciprocal intranodal rhythm, as is said classically, but to a reciprocal rhythm using in the anterograde direction the normal pathways and in a retrograde direction a direct atrio-ventricular bundle in which only retrograde conduction is possible. This explains the absence of any patent preexcitation pattern on tracings in sinus rhythm. The authors particularly stress the value of a sign recorded at the onset of an attack of tachycardia: transient slowing of the rate of the tachycardia when functional bundle branch block is present can only be explained by the existence of a latent preexcitation bundle on the side of the "slowing bundle branch block".
Bundle-Branch Block↗
[Right branch block with left anterior hemiblock; transitory disappearance of the left anterior hemiblock].
Explore the source record for details and available documents.
Aged↗
Multiform ventricular ectopic rhythm. Evidence for multiple parasystolic activity.
Six patients whose standare electrocardiograms showed multiform ventricular ectopic rhythm were studied. All patients had advanced organic heart disease and a significant intraventricular conduction defect (left bundle branch block in five and right bundle branch block plus left anterior hemiblock in one). The ventricular arrhythmia was generally resistant to antiarrhythmic therapy. Five of the six patients died after 2 to 6 months form the period of observation from terminal heart failure. None died suddenly. The ventricular arrhythmia did not seem to be directly related to mortality in any patient. Critical analysis of several long rhythm strips in each case revealed that discharge from multiple ventricular parasytolic foci shared in the multiform ventricular activity. The concurrent discharge of a minimum of three parasytolic foci and a maximum of six foci was found in the same case with a total of 24 parasystolic foci in the six patients. There was a remarkable constancy of the QRS configuration of all parasytolic foci over periods of observation of up to 16 months. However, 22 out of 24 parasystolic rhythms showed significant variation in the apparent rhythm or the administration of drugs. Fourteen parasytolic foci showed evidence of exit block, some of which were exaples of a rapid parasystole with a high degree of exit block. The study suggests that multiform ventricular ectopic rhythm may, in part, be due to the concurrent discharge of multiple parasystolic foci.
Aged↗
[Ventricular extrasystoles presenting a pattern of left bundle branch block. Vectorcardiographic analysis of the initial phase of ventricular depolarization].
Explore the source record for details and available documents.
Adult↗
Lack of sensing by demand pacemakers due to intraventricular conduction defects.
A previously unrecognized form of failure of normally functioning noncompetitive R-inhibited or R-triggered pacemakers to sense is described in 30 patients. The failure was produced by the delayed arrival of ventricular depolarization due to intraventricular conduction disturbances at the site of pacemaker sensing electrodes. These patinets with late activation of the right ventricle exhibited right bundle branch block (RBBB) during conducted sinus beats or had ectopic beats arising from the left ventricle. In both these situations, several late occurring QRS complexes were not sensed by the pacemaker electrodes in the right ventricular apex (RVA) and thereby the R-inhibited pacemaker spike discharged into the initial portion of the QRS complex. Activation of the RVA was delayed up to 65 msec in sinus beats with RBBB and even longer in premature beats arising from the left ventricle. The depolarization front of such beats reached the myocardium around the right ventricular pacemaker electrodes late in the QRS and thereby were not sensed up to 65 msec after the QRS onset as seen on the surface electrocardiogram (ECG). It was found in this study that if the inscription of such QRS complexes began up to 65 msec before the next due pacemaker impulse, these complexes were not sensed, allowing discharge of normally functioning R-inhibited pacemakers within the QRS which mimicked pacemaker malfunction. Failure to sense due to this phenomenon was observed in patients with noncompetitive pacemakers, both R-inhibited and R-triggered; temporary and permanent; with unipolar as well as bipolar electrodes. Similarly, patients with left ventricular epicardial electrodes and left bundle branch block in sinus beats also exhibited this phenomenon. Complete evaluation proved that pacemaker function was normal in the entire patient group. Recognition that failure to sense was the result of intraventricular conduction disorder prevented the untimely replacement of the pulse generator. This phenomenon of nonsensing by noncompetitive pacemakers should be considered in the presence of wide QRS complexes before the pacemaker is concluded to be malfunctioning.
Aged↗
Prognostic value of early changes in the frontal QRS-T angle in patients with heart failure and left bundle branch block undergoing cardiac resynchronization therapy.
BACKGROUND: Cardiac resynchronization therapy (CRT) reduces morbidity and mortality in selected patients with heart failure (HF). The frontal QRS-T angle (FQTA), reflecting ventricular depolarization-repolarization heterogeneity, has been associated with major adverse cardiovascular events (MACE). We aimed to assess the prognostic value of changes in the FQTA after CRT in predicting long-term MACE. METHODS: A total of 223 consecutive HF patients with left bundle branch block who underwent CRT between 2018 and 2022 were retrospectively analyzed. The FQTA was measured before and after CRT, and the change (ΔFQTA) was calculated. Receiver operating characteristic (ROC) analysis was performed to determine the optimal cutoff value for predicting the primary outcome, MACE. Patients were subsequently stratified according to this cutoff value. Independent predictors were identified using multivariable Cox proportional hazards regression analysis. RESULTS: ROC analysis identified 22.5° as the optimal cutoff value for predicting MACE (AUC: 0.711; 95% CI: 0.642-0.781; p < 0.001). During a mean follow-up of 34.6 ± 17.6 months, patients with ΔFQTA <22.5° had a significantly higher incidence of MACE compared with those with greater angle reduction (44.7% vs. 11.9%; p < 0.001). In multivariable Cox regression analysis, chronic kidney disease (HR: 2.517; p = 0.002) and ΔFQTA <22.5° (HR: 4.56; p < 0.001) were independently associated with MACE. CONCLUSION: A greater reduction in FQTA after CRT is associated with improved long-term outcomes and may serve as a practical electrocardiographic marker for risk stratification.
Humans↗
Intracardiac electrography in children and young adults.
The interpretation of IE recorded in children has been hampered by a lack of agreement regarding normal values. We recorded IE in 158 children and young adults (ages, three days to 33 years) to define the various conduction intervals in normal and disease states. The HBP was recorded in 156 subjects. In 85 subjects with normal conduction indicated by surface ECG, including 19 subjects with normal hearts, there were no statistically significant age-related differences in internodal, A-V nodal, or His-Purkinje conduction intervals. Therapeutic levels of digitalis did not alter the conduction intervals. In 11 subjects with first degree A-V block and in five subjects with congenital complete A-V block, the site of block as determined by IE could not be predicted from the surface ECG. No abnormalities in conduction intervals were found in 18 subjects with right bundle branch block (surgically induced in 17 cases). Intracardiac electrography with recording of the HBP was found to be a safe, informative technique for electrophysiologic investigations in children and young adults.
Adolescent↗
Tachyarrhythmias and transient cerebral ischemic attacks.
Explore the source record for details and available documents.
Arrhythmia, Sinus↗
Effects of lidocaine on impulse formation and conduction defects in man.
The acute electrophysiologic effects of a bolus injection of 100 mg. of lidocaine were investigated in 39 patients with impulse formation and conduction defects by means of His-bundle recording and were correlated with plasma lidocaine levels. The effects of therapeutic plasma levels on conduction intervals and refractory periods were subsequently studied during sinus rhythm and atrial pacing. The sinus-node function was studied by measurement of the sino-atrial recovery time. Seventeen patients had conduction defects in or distal to the His bundle, six exclusively proximal to the His bundle, and nine at both levels. Nine patients had pre-existent sinus-node malfunction. Ten out of 39 patients suffered from acute myocardial infarction. Two patients were studied twice because of changed A-V conduction. Intravenous injection of 100 mg. of lidocaine within 20 seconds produced peak arterial plasma levels (mean 26.6 mug per milliliter) 60 seconds after the beginning of the injection. Seven out of 26 patients showed transient progression of their pre-existent infra-His conduction impairment, coincident with peak plasma levels, apparently due to drug toxicity. Even at therapeutic plasma levels, five out of 26 patients showed decremental intraventricular conduction during atrial pacing when compared to control tracings. His-Purkinje refractoriness was not shortened in these patients and increased in two. Lidocaine had no effect on ventricular automaticity in three patients with complete heart block. Lidocaine had no consistent effects on sinus rate, SART, atrial refractoriness, or A-V nodal conduction as measured by pooled AH intervals and the Wenckebach point, and on A-V nodal refractoriness. It is concluded that lidocaine is safe in patients with high degrees of A-V nodal block and in patients with impulse formation disturbances. However, patients with intraventricular conduction defects are prone to deterioration of their conduction disturbance due to drug toxicity. The drug should be given to such patients preferably if monitoring and pacemaker facilities are available and by the intramuscular route to avoid peak plasma levels.
Adult↗
Feasibility and efficacy of left bundle branch area pacing guided by modified chest lead 1.
BACKGROUND: Left bundle branch area pacing (LBBAP) typically requires 12‑lead electrocardiogram (ECG) measurements using an electrophysiology (EP) recording system. However, a simplified approach using modified chest lead 1 (MCL1) is potentially feasible. This study aimed to compare the success rate and pacing outcomes of LBBAP guided by MCL1 with those guided by the 12‑lead ECG using an EP recording system. METHODS: This retrospective, single-center study included patients with preserved left ventricular ejection fraction who underwent LBBAP for bradyarrhythmia. LBBAP was either guided by 12‑lead ECG using an EP recording system or by MCL1. In the MCL1 group, a follow-up examination with a 12‑lead ECG using an EP recording system was conducted within one week postoperatively. RESULTS: A total of 65 patients underwent LBBAP (EP recording system group: n = 35; MCL1 group: n = 30). The overall success rate of LBBAP was 84.6%, with no significant difference between groups (88.5% vs. 80.0%, p = 0.49). No significant differences were observed in the paced QRS duration (140.4 ± 8.0 vs. 141.9 ± 13.1 ms, p = 0.54), V6-V1 interpeak interval (39.7 ± 16.5 vs. 38.3 ± 15.6 ms, p = 0.79), or V6 R-wave peak time (69.8 ± 12.3 vs. 71.5 ± 12.1 ms, p = 0.68). CONCLUSIONS: MCL1-guided LBBAP was feasible and achieved a high success rate, with outcomes comparable to those of conventional EP recording system-guided implantation. This simplified approach may reduce procedural complexity and may allow LBBAP implantation without the routine use of an EP recording system.
Humans↗
Ultra-high-frequency ECG quantifies residual electrical dyssynchrony during left bundle branch area pacing in patients with wide QRS: a paired within-patient study.
BACKGROUND: Left bundle branch area pacing (LBBAP) may restore a more physiological pattern of ventricular activation in patients with conduction delay; however, QRS narrowing alone may incompletely characterize electrical resynchronization. Ultra-high-frequency ECG (UHF-ECG) provides quantitative markers of ventricular activation timing and dyssynchrony. OBJECTIVE: To quantify paired OFF-to-ON changes in conventional ECG and UHF-ECG metrics during LBBAP in patients with baseline wide QRS and to assess the relationship between paced R-wave peak time (RWPT) and residual UHF-ECG dyssynchrony. METHODS: In this prospective single-center paired study, 21 patients with bradycardia and baseline wide QRS underwent standard ECG and UHF-ECG assessment during intrinsic rhythm (pacing OFF) and during LBBAP (pacing ON). Endpoints included QRS duration, signed VED16, absolute VED16 (|VED16|), mean ventricular delay (meanVD), and a clinically interpretable distance-to-normal metric defined as dist = max(|VED16|-20, 0). Paired changes were summarized as medians with bootstrap 95% confidence intervals and tested using the Wilcoxon signed-rank test. Associations between paced RWPT and residual dyssynchrony during pacing were evaluated using Pearson and Spearman correlation coefficients. RESULTS: LBBAP significantly narrowed QRS duration from 136.8 [130.2-153.6] ms during intrinsic rhythm to 116.0 [107.8-125.6] ms during pacing (median Δ -21.0 ms; 95% CI -33.9 to -18.6; p < 0.001). Signed VED16 did not change significantly (median Δ 0.4 ms; p = 1.000), consistent with the mixed conduction-phenotype composition of the cohort. In contrast, severity-oriented UHF-ECG endpoints improved: |VED16| decreased numerically (median Δ -5.2 ms; p = 0.070), whereas dist decreased significantly (median Δ -0.7 ms; 95% CI -14.4 to 0.0; p = 0.015). The proportion of patients within the normal dyssynchrony band (|VED16| ≤ 20 ms) increased from 7/21 (33.3%) to 12/21 (57.1%). Median paced RWPT was 66.6 [58.6-74.6] ms, and shorter RWPT correlated with lower residual |VED16| during pacing (Pearson r = -0.45, p = 0.038). CONCLUSIONS: In patients with baseline wide QRS, LBBAP produces marked QRS narrowing, whereas UHF-ECG provides complementary quantification of residual electrical dyssynchrony. Severity-oriented UHF-ECG endpoints, particularly a distance-to-normal metric, may offer an interpretable mechanistic framework beyond conventional ECG alone. Shorter paced RWPT was associated with lower residual dyssynchrony during pacing, supporting physiological coherence between procedural and high-resolution electrocardiographic markers.
Humans↗
Characteristics of ventricular extrasystoles and their prognostic importance: a reappraisal of their method of classification.
The concept of two different types of extrasystoles, parasystolic and coupled, depends upon two distinguishing characteristics of these beats. The characteristics of the parasystolic extrasystoles are the invariability of the ectopic cycle together with their independence from the basic rhythm. Coupled extrasystoles demonstrate a dependence upon the basic rhythm although they may express some degree of ectopic variability. The degree of variation of the interectopic interval or its common denominator measures the irregularity of the ectopic parasystolic rhythm. The variation of coupling intervals describes the dependence of the ectopic beat upon the basic rhythm. In a study of 719 electrocardiograms with ventricular extrasystoles, about one-third of the extrasystoles appeared intermediate between these types since they had both variable coupling intervals and variable interectopic intervals. Some of these had total variability of coupling intervals and of the interectopic intervals (random non-parasystolic coupling), and others had limited variation of coupling intervals when expressed in relationship to the total duration of electrical diastole (approximate non-parasystolic coupling). Both these ectopic types appeared to be associated with cardiac disease, and repetitive ventricular extrasystoles. Left bundle branch type extra-with fixed coupling. There were no obvious relationships between the contour and the type of coupling of ventricular extrasystoles. Left bundle branch type extrasystoles with vertical or right axis were the most frequent, particularly in normal subjects, but in the presence of cardiac disease there were more electrocardiograms with right bundle branch type extrasystoles. Extrasystoles in the presence of underlying conduction defects were usually of opposite configuration to this defect. The contour of uniform extrasystoles did not appear to predispose to serious ventricular arrhythmias but multiformity of extrasystoles was an important prognostic indicator. It is suggested that variability of contour and coupling are important signs of inhomogenous conduction and may precede the onset of severe ventricular arrhythmias. Random nonparasystolic coupling and marked multiformity indicate a more sinister arrhythmic state.
Bundle of His↗
[Arrhythmias in acute myocardial infarct. Personal experience with follow-up of a group of 122 patients hospitalized in the period 1974-1975].
Explore the source record for details and available documents.
Acute Disease↗
[Disorders of intracardiac conduction in anesthesia-resuscitation].
Explore the source record for details and available documents.
Anesthesia, General↗
Procainamide-induced lupus syndrome in siblings.
Explore the source record for details and available documents.
Aged↗