Related Experiment Video
Updated: May 30, 2026
10:17
Real-Time Cardiac Mapping with a Noninvasive Imageless Electrocardiographic Imaging System
Published on: April 11, 2025
Ventricular repolarization during uni and biventricular pacing in normal subjects.
Abdel J Fuenmayor1, María Eugenia Delgado
1Electrophysiology and Arrhythmias Section, Cardiovascular Research Institute Abdel M. Fuenmayor P, University of The Andes, Mérida, Venezuela. ajf@cantv.net
International Journal of Cardiology
|August 20, 2011
Summary
Cardiac pacing affects the depolarization-repolarization process (D-REPP). Biventricular pacing causes less D-REPP disturbance than single-chamber pacing, impacting intervals like QRS and QT.
Area of Science:
- Cardiology
- Electrophysiology
Background:
- Cardiac depolarization-repolarization (D-REPP) can vary with pacing mode and lead placement.
- Understanding these variations is crucial for optimizing cardiac pacing strategies.
Purpose of the Study:
- To evaluate how different cardiac pacing modes (right, left, biventricular) influence D-REPP.
- To compare electrophysiological intervals during pacing versus sinus rhythm.
Main Methods:
- 31 patients with normal cardiac function were studied.
- 12-lead ECGs were recorded during right, left, and biventricular pacing.
- Measurements included QRS, QT, corrected QT (cQT), peak-to-end of T wave (PETW), and PETW/QT ratio.
Main Results:
- All pacing modes increased D-REPP intervals compared to sinus rhythm.
- Right and left ventricular pacing similarly increased intervals.
- Biventricular pacing also increased intervals, but to a lesser extent than univentricular pacing.
Conclusions:
- Cardiac pacing significantly alters D-REPP in patients without structural heart disease.
- Univentricular pacing (right or left) showed no significant differences.
- Biventricular pacing results in less perturbation of the cardiac depolarization-repolarization process.
Related Concept Videos
01:19Electrophysiology of Normal Cardiac Rhythm
The normal cardiac rhythm is a synchronized electrical activity that facilitates the regular and coordinated contraction of the heart muscle. This process is essential for efficient blood circulation throughout the body. The fundamental elements involved in establishing and maintaining this rhythm include the unique electrical properties of cardiac muscle cells, the sinoatrial (SA) node's pacemaker function, the specialized conducting system, and the ionic mechanisms underlying each phase of...
01:30Cardiac 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
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
01:18Dysrhythmias 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...
01:25ECG 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...
01:25Correlation 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...
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...
01:29Dysrhythmias 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.