Related Experiment Video

Updated: Aug 17, 2026

Methods for ECG Evaluation of Indicators of Cardiac Risk, and Susceptibility to Aconitine-induced Arrhythmias in Rats Following Status Epilepticus
08:28

Methods for ECG Evaluation of Indicators of Cardiac Risk, and Susceptibility to Aconitine-induced Arrhythmias in Rats Following Status Epilepticus

Published on: April 5, 2011

QRS duration does not predict occurrence of ventricular tachyarrhythmias in patients with implanted

Alfred E Buxton1, Michael O Sweeney, Mark S Wathen

  • 1Cardiology Division, Department of Medicine, Brown Medical School, Providence, Rhode Island 02905, USA.

Journal of the American College of Cardiology
|July 19, 2005
PubMed

Insights

QRS duration and ECG conduction abnormalities do not reliably predict ventricular arrhythmias in coronary artery disease patients with implantable cardioverter-defibrillators. Further prospective studies are needed to clarify the utility of QRS duration for predicting these events.

Area of Science:

  • Cardiology
  • Electrophysiology
  • Medical Devices

Background:

  • QRS duration (QRSd) on ECG correlates with mortality in coronary artery disease (CAD) patients at high risk for sudden death.
  • The relationship between QRSd and the risk of ventricular tachyarrhythmias (VT/VF) in CAD patients is not well-defined.

Purpose of the Study:

  • To investigate the correlation between QRS duration and the occurrence of ventricular arrhythmias in CAD patients receiving implantable cardioverter-defibrillators (ICDs).

Main Methods:

  • Retrospective analysis of the PainFREE Rx II trial data.
  • Correlated QRS duration and ECG conduction abnormalities with VT/VF occurrence in 431 CAD patients with ICDs.

Main Results:

  • No significant difference in VT/VF occurrence was observed between patients with QRSd ≤120 ms and those with QRSd >120 ms (22% vs. 23%, p=NS).
  • Left bundle branch block (LBBB) was associated with a lower likelihood of VT/VF compared to QRSd <120 ms.
  • Right bundle branch block (RBBB) and non-specific intraventricular conduction delay (IVCD) did not show a different risk for tachyarrhythmias compared to narrow QRS complexes.

Conclusions:

  • QRS duration and ECG conduction abnormalities are not effective predictors of ICD benefit in this patient population.
  • Further prospective evaluation is required to determine the utility of QRS duration in predicting VT/VF events in CAD patients.
Abstract

More Related Videos

In Vivo Surface Electrocardiography for Adult Zebrafish09:13

In Vivo Surface Electrocardiography for Adult Zebrafish

Published on: August 1, 2019

Related Concept Videos

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...
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...
Disturbances in Heart Rhythm01:29

Disturbances in Heart Rhythm

Arrhythmia or dysrhythmia refers to an abnormal heart rhythm caused by a defect in the heart's conduction system. It can cause the heart to beat irregularly, too quickly, or too slowly, leading to symptoms like chest pain, shortness of breath, and fainting. Factors such as stress, caffeine, alcohol, nicotine, cocaine, certain drugs, congenital defects, diseases, and electrolyte abnormalities can trigger arrhythmias.
Arrhythmias are categorized by their speed, rhythm, and origin. A slow heart...
Dysrhythmias III: Characteristics of Dysrhythmias01:29

Dysrhythmias III: Characteristics of Dysrhythmias

Dysrhythmias, also known as arrhythmias, are irregular heart rhythms that result from abnormal electrical activity in the heart, affecting its ability to circulate blood efficiently. Tachyarrhythmias, a subset of dysrhythmias, are characterized by abnormally fast heart rates exceeding 100 beats per minute. Here are some types of tachyarrhythmias with their distinct ECG features:Sinus Tachycardia:Sinus tachycardia presents a regular heart rhythm with an increased rate of 101-180 beats per minute.
Dysrhythmias II: Classification of Tachyarrhythmias01:28

Dysrhythmias II: Classification of Tachyarrhythmias

Tachyarrhythmias are a type of dysrhythmia where the heart rate exceeds 100 beats per minute. Here are some common types of tachyarrhythmias:Sinus TachycardiaSinus tachycardia originates from increased impulses from the sinus node, leading to an elevated heart rate. It is often triggered by stress, fever, or exercise.Patients may experience palpitations, a sensation of a racing heart, dizziness, and chest discomfort.Causes and Risk Factors: Common causes include physical exertion, emotional...
Cardiac Action Potential01:30

Cardiac Action Potential

Cardiac action potentials are essential for proper heart function, enabling the rhythmic contractions needed for adequate blood circulation. Nodal cells and Purkinje fibers, specialized for electrical conduction, generate these action potentials.
The cardiac action potential process involves a series of phases characterized by the movement of ions across the cardiac cell membranes, leading to the depolarization and repolarization of the cardiac myocytes.
Ionic Basis of Cardiac Action Potentials