Jove
Visualize
Contact Us
JoVE
x logofacebook logolinkedin logoyoutube logo
ABOUT JoVE
OverviewLeadershipBlogJoVE Help Center
AUTHORS
Publishing ProcessEditorial BoardScope & PoliciesPeer ReviewFAQSubmit
LIBRARIANS
TestimonialsSubscriptionsAccessResourcesLibrary Advisory BoardFAQ
RESEARCH
JoVE JournalMethods CollectionsJoVE Encyclopedia of ExperimentsArchive
EDUCATION
JoVE CoreJoVE BusinessJoVE Science EducationJoVE Lab ManualFaculty Resource CenterFaculty Site
Terms & Conditions of Use
Privacy Policy
Policies

Related Concept Videos

Criteria for Causality: Bradford Hill Criteria - II01:28

Criteria for Causality: Bradford Hill Criteria - II

1.2K
The Bradford Hill criteria serve as guidelines for establishing causative links in epidemiological research. Beyond Strength, Consistency, Specificity, and Temporality, key criteria also include Biological Gradient, Plausibility, Coherence, Experiment, and Analogy. These principles assist scientists in assessing the likelihood of causation in complex biological contexts. Below is a summary of these concepts:
1.2K
Criteria for Causality: Bradford Hill Criteria - I01:30

Criteria for Causality: Bradford Hill Criteria - I

1.1K
The Bradford Hill criteria are a group of principles that provide a framework to determine a causal relationship between a specific factor and a disease. There are nine criteria that are pivotal in assessing causality in epidemiological studies. Here's a closer look at Strength, Consistency, Specificity, and Temporality criteria with definitions and examples:
1.1K
Electro-mechanical Systems01:19

Electro-mechanical Systems

1.6K
Electromechanical systems are intricate configurations that effectively combine electrical and mechanical elements to achieve a desired outcome. Central to many of these systems is the DC motor, a device that converts electrical energy into mechanical motion, enabling various applications ranging from simple fans to complex robotic mechanisms.
A key component of the DC motor is the armature, a rotating circuit positioned within a magnetic field. As an electric current passes through the...
1.6K
Yield Criteria for Ductile Materials under Plane Stress01:25

Yield Criteria for Ductile Materials under Plane Stress

505
In designing structural elements and machine parts using ductile materials, it is crucial to ensure that these components withstand applied stresses without yielding. Yielding is initially determined through a tensile test, which evaluates the material's response to uniaxial stress. However, tensile stress is insufficient when components face biaxial or plane stress conditions This condition requires advanced criteria to predict failure.
The Maximum Shearing Stress Criterion, also known as...
505
Criteria for Aromaticity and the Hückel 4n + 2 Rule01:20

Criteria for Aromaticity and the Hückel 4n + 2 Rule

13.0K
Like benzene, cyclobutadiene and cyclooctatetraene are cyclic compounds with alternate single and double bonds. However, their chemical behavior differs from benzene, as they are unstable and not aromatic. So, what are the structural characteristics of unsaturated compounds categorized as aromatic?  
For the first time, Eric Hückel, a German chemical physicist, derived a set of structural features for a compound to be classified as aromatic. This is now known as Hückel’s rule or the 4n +...
13.0K
Block Diagram Reduction01:22

Block Diagram Reduction

548
The process of deriving the transfer function of a control system often involves reducing its block diagram to a single block. This simplification can be achieved through a series of strategic operations, including relocating branch points and comparators. These operations preserve the overall function of the system while allowing for easier manipulation and combination of blocks.
The first step in this process is the identification and relocation of a branch point. A branch point, where a...
548

You might also read

Related Articles

Articles linked to this work by shared authors, journal, and citation graph.

Sort by
Same author

Systematic multi-domain screening of lead-specific electrocardiographic features associated with sudden cardiac death.

Journal of electrocardiology·2026
Same author

Coronary Stenosis Location, Revascularization Strategy, and Sudden Cardiac Death in Chronic and Acute Coronary Syndromes.

JACC. Cardiovascular interventions·2026
Same author

Acute atrial fibrillation and flutter treated electively: rationale and design of the randomized controlled AFFELECT trial.

European heart journal open·2026
Same author

A child with a large ostium secundum atrial septal defect, pulmonary hypertension, and the characteristic Crochetage electro-vectorcardiographic pattern.

Journal of electrocardiology·2026
Same author

Prognostic implications of intraventricular conduction disorders for the risk of sudden cardiac death in cardiac patients.

Heart rhythm·2026
Same author

Performance of the 12-lead ECG in predicting short- and long-term risk of sudden cardiac death.

NPJ digital medicine·2026

Related Experiment Video

Updated: Jan 26, 2026

Benefits of Cardiac Resynchronization Therapy in an Asynchronous Heart Failure Model Induced by Left Bundle Branch Ablation and Rapid Pacing
12:45

Benefits of Cardiac Resynchronization Therapy in an Asynchronous Heart Failure Model Induced by Left Bundle Branch Ablation and Rapid Pacing

Published on: December 11, 2017

10.9K

Re-evaluating the electro-vectorcardiographic criteria for left bundle branch block.

Andrés Ricardo Pérez-Riera1, Raimundo Barbosa-Barros2, Rodrigo Daminello-Raimundo1

  • 1Study Design and Scientific Writing Laboratory, ABC Faculty of Medicine, Santo André, São Paulo, Brazil.

Annals of Noninvasive Electrocardiology : the Official Journal of the International Society for Holter and Noninvasive Electrocardiology, Inc
|April 3, 2019
PubMed
Summary

This review discusses how diagnostic criteria for left bundle branch block affect treatment outcomes. Stricter criteria, including longer QRS duration and notching, better identify patients who respond to therapy. Vectorcardiography may improve diagnostic accuracy. ST/T concordance is also a debated but relevant factor. The authors suggest that current criteria may not fully capture LBBB complexity and propose further refinement.

Keywords:
QRS durationQRS notched/slurred R waves in lateral leadscardiac resynchronization therapyconcordant and appropriate discordanceleft bundle branch blockCardiac electrophysiologyElectrocardiographyResynchronization therapyVectorcardiography

Frequently Asked Questions

More Related Videos

Evaluation of Left Ventricular Structure and Function using 3D Echocardiography
06:34

Evaluation of Left Ventricular Structure and Function using 3D Echocardiography

Published on: October 28, 2020

4.6K
Mouse Embryonic Lung Culture, A System to Evaluate the Molecular Mechanisms of Branching
07:32

Mouse Embryonic Lung Culture, A System to Evaluate the Molecular Mechanisms of Branching

Published on: June 30, 2010

18.9K

Related Experiment Videos

Last Updated: Jan 26, 2026

Benefits of Cardiac Resynchronization Therapy in an Asynchronous Heart Failure Model Induced by Left Bundle Branch Ablation and Rapid Pacing
12:45

Benefits of Cardiac Resynchronization Therapy in an Asynchronous Heart Failure Model Induced by Left Bundle Branch Ablation and Rapid Pacing

Published on: December 11, 2017

10.9K
Evaluation of Left Ventricular Structure and Function using 3D Echocardiography
06:34

Evaluation of Left Ventricular Structure and Function using 3D Echocardiography

Published on: October 28, 2020

4.6K
Mouse Embryonic Lung Culture, A System to Evaluate the Molecular Mechanisms of Branching
07:32

Mouse Embryonic Lung Culture, A System to Evaluate the Molecular Mechanisms of Branching

Published on: June 30, 2010

18.9K

Area of Science:

  • Cardiac electrophysiology
  • Electrocardiography diagnostics
  • Cardiac resynchronization therapy outcomes

Background:

Left bundle branch block (LBBB) remains a clinically significant diagnosis. Prior research has shown that traditional LBBB criteria focus on QRS morphology and duration. However, these criteria may not fully capture all diagnostic nuances. No prior work had resolved the variability in response to cardiac resynchronization therapy. This gap motivated a closer look at diagnostic accuracy. Some studies suggest that stricter criteria improve patient selection for therapy. Yet, the role of ST/T concordance remains debated. Vectorcardiography may offer additional insights into LBBB morphology. This paper addresses these unresolved questions.

Purpose Of The Study:

This study aims to re-evaluate diagnostic criteria for left bundle branch block. The authors propose examining how criteria influence treatment outcomes. A specific problem is the variability in response to cardiac resynchronization therapy. The motivation comes from observed inconsistencies in patient responses. The authors suggest that stricter criteria may better identify suitable candidates. They also explore the role of vectorcardiography in refining diagnosis. The study does not propose new criteria but reviews existing ones. It focuses on how these criteria affect clinical decisions.

Main Methods:

The study uses a review approach to analyze existing literature. It synthesizes findings on diagnostic criteria for LBBB. The authors examine QRS duration and morphology as key indicators. They also consider ST/T concordance in ECG readings. Vectorcardiography data is included to assess diagnostic accuracy. The review compares different criteria sets and their prognostic value. No new experiments are performed in this work. The focus is on how diagnostic criteria impact therapy outcomes.

Main Results:

Stricter criteria, including longer QRS duration, better identify therapy responders. QRS slurring and notching are proposed as important features. ST/T concordance is linked to better outcomes in some studies. Vectorcardiography may enhance diagnostic precision in LBBB cases. No single criterion universally predicts therapy success. The review suggests that morphology alone is insufficient for diagnosis. Concordance patterns may help differentiate true LBBB from mimics. These findings suggest a need for refined diagnostic approaches.

Conclusions:

The authors propose that stricter criteria improve patient selection for therapy. They suggest that QRS morphology and duration are key indicators. Vectorcardiography may add value in diagnosing LBBB. ST/T concordance is a debated but relevant factor. The review does not propose new criteria but highlights gaps. It suggests that current criteria may not fully capture LBBB complexity. The authors emphasize the need for further refinement in diagnostic standards. Their findings align with prior studies showing variability in therapy outcomes.

Stricter criteria, including longer QRS duration and notching, better identify responders to therapy.

Vectorcardiography may enhance diagnostic accuracy by providing additional morphological insights.

ST/T concordance is linked to better therapy outcomes and may help differentiate true LBBB from mimics.

QRS slurring is proposed as a key feature in identifying true LBBB cases.

Morphology alone may not fully predict therapy success, suggesting a need for refined criteria.

The authors suggest stricter criteria and the inclusion of vectorcardiography for better diagnosis.