Related Experiment Video
Updated: May 22, 2026
08:05
Optimization of Transesophageal Atrial Pacing to Assess Atrial Fibrillation Susceptibility in Mice
Published on: June 29, 2022
Pacemaker repetitive nonreentrant ventriculoatrial synchrony. Why did automatic mode switching occur?
S Serge Barold1, Roland X Stroobandt2, Frederic Van Heuverswyn2
1Florida Heart Rhythm Institute, Tampa, FL.
Journal of Electrocardiology
|May 8, 2012
Summary
Repetitive ventriculoatrial synchrony can trick dual-chamber pacemakers into switching modes unexpectedly. This occurs due to specific long and short interval patterns that activate the automatic mode switching algorithm.
Area of Science:
- Cardiology
- Biomedical Engineering
- Electrophysiology
Background:
- Dual-chamber pacemakers are crucial for managing bradycardia and heart rhythm disorders.
- Understanding pacemaker-patient interactions is vital for optimizing therapy and preventing adverse events.
Observation:
- Repetitive nonreentrant ventriculoatrial synchrony presents as alternating long and short intervals.
- This specific pacing pattern triggered automatic mode switching in a St. Jude dual-chamber pacemaker.
Findings:
- The pacemaker's algorithm requires an atrial sensed event for automatic mode switching initiation.
- Activation occurred despite the postventricular atrial period being longer than the retrograde ventriculoatrial conduction time, a seemingly paradoxical observation.
Implications:
- This clarifies a complex pacemaker behavior, aiding clinicians in troubleshooting and programming.
- Understanding these intricate timing cycles improves patient management and device efficacy.
- Facilitates better comprehension of pacemaker function in challenging electrophysiological scenarios.
Related Concept Videos
01:28Mechanism of Cardiac Arrhythmias
Arrhythmias are irregular heart rhythms occurring when the heart's electrical impulses become abnormal. These disturbances can lead to various symptoms, depending on their severity and the underlying cause. Some common factors contributing to arrhythmias include hypoxia, ischemia, electrolyte imbalances, excessive catecholamine exposure, drug toxicity, and muscle overstretching. Arrhythmias can be classified into two main types based on the rate and site of origin of abnormal heart rhythms.
01:19Conduction System of the Heart
Autorhythmicity is a term that refers to the heart's inherent ability to generate electrical signals and instigate muscle contractions. This self-regulating conduction system within the heart consists of two key components: the pacemaker cells and specialized conducting cells.
The pacemaker cells are located in two primary nodes: the sinoatrial (SA) node and the atrioventricular (AV) node. The SA node pacemaker cells can autonomously depolarize, triggering an action potential that leads to the...
The pacemaker cells are located in two primary nodes: the sinoatrial (SA) node and the atrioventricular (AV) node. The SA node pacemaker cells can autonomously depolarize, triggering an action potential that leads to the...
01:20Conduction System of the Heart
The cardiac conduction system produces and transmits electrical impulses that prompt myocardial contraction, ensuring efficient heart function. This intricate system ensures that the heart beats in a coordinated and efficient manner, beginning with the atria and then the ventricles. The conduction system optimizes cardiac output by maintaining this precise sequence, which is crucial for adequate blood circulation.
This system relies on the unique properties of nodal and Purkinje cells:...
This system relies on the unique properties of nodal and Purkinje cells:...
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...
01:29Disturbances 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...
Arrhythmias are categorized by their speed, rhythm, and origin. A slow heart...
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.