Related Experiment Video

Updated: Jan 2, 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

Progression of incomplete toward complete left bundle branch block: A clinical and electrocardiographic analysis

Ellie Senesael1, Simon Calle1, Victor Kamoen1

  • 1Department of Cardiology, University Hospital Gent, Gent, Belgium.

Annals of Noninvasive Electrocardiology : the Official Journal of the International Society for Holter and Noninvasive Electrocardiology, Inc
|December 12, 2019
PubMed

Insights

Incomplete left bundle branch block (iLBBB) can progress to complete left bundle branch block (cLBBB) in up to one-third of patients. QRS notching/slurring in lateral leads is a key predictor of this progression.

Area of Science:

  • Cardiology
  • Electrophysiology
  • Internal Medicine

Background:

  • Complete left bundle branch block (cLBBB) is linked to poor cardiovascular outcomes.
  • The clinical significance of incomplete left bundle branch block (iLBBB) remains less understood.
  • This study examines the characteristics and prognosis of iLBBB patients, including progression to cLBBB.

Purpose of the Study:

  • To investigate the patient profile of incomplete left bundle branch block (iLBBB).
  • To assess the outcome and progression rate of iLBBB to complete left bundle branch block (cLBBB).
  • To identify predictors for iLBBB progression to cLBBB.

Main Methods:

  • Retrospective analysis of 321 patients diagnosed with iLBBB between July 2013 and April 2018.
  • Evaluation of echocardiographic and electrocardiographic data at diagnosis and during follow-up.
  • Assessment of progression to non-strict and strict cLBBB.

Main Results:

  • During a median follow-up of 21 months, 33% progressed to non-strict cLBBB and 27% to strict cLBBB.
  • Patients progressing to cLBBB were older with reduced ejection fraction and more QRS notching/slurring.
  • QRS notching/slurring in lateral leads independently predicted progression (OR 4.64 for non-strict, OR 9.6 for strict cLBBB).

Conclusions:

  • Up to one-third of iLBBB patients may progress to cLBBB within two years.
  • QRS notching/slurring in lateral leads is the strongest predictor of progression from iLBBB to cLBBB.
  • Identifying these predictors aids in risk stratification and management of iLBBB patients.
Abstract

Keywords:
QRS notchingcomplete left bundle branch blockincomplete left bundle branch block

More Related Videos

Real-Time Cardiac Mapping with a Noninvasive Imageless Electrocardiographic Imaging System10:17

Real-Time Cardiac Mapping with a Noninvasive Imageless Electrocardiographic Imaging System

Published on: April 11, 2025

1.5K
Evaluation of Left Ventricular Structure and Function using 3D Echocardiography06:34

Evaluation of Left Ventricular Structure and Function using 3D Echocardiography

Published on: October 28, 2020

4.5K

Related Concept Videos

Dysrhythmias IV: Characteristics of Bradyarrhythmias01:18

Dysrhythmias IV: Characteristics of Bradyarrhythmias

Bradyarrhythmias are cardiac rhythm disorders characterized by a slower-than-normal heart rate, typically defined as fewer than 60 beats per minute. Some of which are discussed here:Sinus BradycardiaSinus bradycardia presents a heart rate lower than 60 beats per minute, with a regular rhythm originating from the SA node. The ECG typically shows normal P waves preceding each QRS complex, a normal PR interval (0.12 to 0.20 seconds), and a normal QRS duration (0.06 to 0.10 seconds).First-Degree AV...
411
Electrocardiogram Fundamentals01:28

Electrocardiogram Fundamentals

Introduction
An electrocardiogram (ECG) is a diagnostic tool for identifying cardiac conditions such as arrhythmias, conduction abnormalities, and myocardial ischemia.
Definition
An electrocardiogram (ECG) visualizes the heart's electrical activity by tracing the electrical movement associated with each heartbeat on a graph or monitor. As the heart beats, an electrical wave passes through it, correlating with the cardiac cycle events.
Parts of an ECG
An ECG utilizes electrodes on the skin...
1.3K
Mitral Stenosis II: Clinical features and Diagnostic Tests01:23

Mitral Stenosis II: Clinical features and Diagnostic Tests

Mitral stenosis is a heart condition in which the mitral valve, which allows blood to flow from the left atrium to the left ventricle, becomes narrowed or stenotic. This narrowing hinders blood flow and leads to clinical symptoms requiring specific medical evaluations and management strategies. The following overview outlines the clinical symptoms, assessments, diagnostic findings, prevention methods, and treatments for mitral stenosis.Clinical ManifestationsDyspnea (shortness of breath): This...
175
Correlation between ECG and Cardiac Cycle01:25

Correlation between ECG and Cardiac Cycle

The electrical signals recorded on an electrocardiogram (ECG) occur before the mechanical processes of contraction and relaxation during the cardiac cycle.
A cardiac action potential originates in the SA node and spreads throughout the atria and the AV node in approximately 0.03 seconds. This results in the P wave in an ECG and triggers atrial contraction. The action potential is then briefly slowed at the AV node, allowing the atria to contract and fill the ventricles with blood before...
11.4K
Electrocardiogram01:29

Electrocardiogram

An electrocardiogram (ECG or EKG) is a critical diagnostic tool that records the electrical signals produced by the heart during each heartbeat. This recording is achieved through electrodes placed strategically on the arms, legs, and chest. The electrocardiograph amplifies these signals and produces 12 distinct tracings, offering a comprehensive understanding of the heart's electrical activity.
Three major waveforms are present in a typical ECG recording: the P wave, the QRS complex, and...
5.2K
ECG Interpretation of Arrhythmias II: Atrial, Junctional and Ventricular Arrhythmias01:25

ECG Interpretation of Arrhythmias II: Atrial, Junctional and Ventricular Arrhythmias

Arrhythmia is a condition characterized by an irregular heart rhythm, with ECG changes that differ based on its origin and nature. The types of arrhythmias discussed below include atrial, junctional, and ventricular arrhythmias.Atrial ArrhythmiasPremature Atrial Complexes (PACs): PACs are early atrial beats caused by stress, caffeine, alcohol, electrolyte imbalances, hypoxia, hyperthyroidism, or certain medications (e.g., bronchodilators and decongestants). The ECG shows early P waves with an...
394