Related Experiment Video
Updated: Oct 15, 2025
04:22
Author Spotlight: Advancing Human Cardiac Anatomy Through Multi-Scale Analysis of Hearts
Published on: June 28, 2024
646
Atrioventricular Conduction: Physiology and Autonomic Influences
Eric N Prystowsky1, Jasen L Gilge2
1Cardiac Arrhythmia Service, St. Vincent Hospital, 8333 Naab Road, Indianapolis, IN 46260, USA; Duke University Medical Center, Durham, NC, USA.
Cardiac Electrophysiology Clinics
|October 25, 2021
Summary
Sudden heart block often indicates increased vagal tone affecting the atrioventricular (AV) node. However, heart block with activity suggests a His-Purkinje system issue, influenced by autonomic nervous system changes.
Area of Science:
- Cardiology
- Electrophysiology
- Autonomic Nervous System
Background:
- Atrioventricular (AV) nodal conduction exhibits decremental properties and is sensitive to autonomic tone.
- His-Purkinje system (HPS) conduction relies on fast-channel tissue, showing less dependence on autonomic variations.
Purpose of the Study:
- To differentiate the origins of heart block based on autonomic influences.
- To correlate specific patterns of heart block with the affected cardiac conduction system.
Main Methods:
- Analysis of electrophysiological principles governing AV nodal and HPS conduction.
- Correlation of clinical presentations of heart block with underlying autonomic tone.
Main Results:
- Sudden heart block during stable sinus rhythm, especially with preceding rate slowing, typically implicates the AV node due to increased vagal tone.
- Heart block accompanied by His-Purkinje system activity strongly suggests block within the HPS.
- Enhanced sympathetic and reduced vagal tone can promote AV and atrioventricular node reentry.
Conclusions:
- Autonomic tone significantly impacts AV nodal function, serving as a key differentiator for heart block etiology.
- Understanding the interplay between autonomic tone and conduction system properties is crucial for diagnosing heart block.
Related Concept Videos
01:19Conduction System of the Heart
10.7K
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...
10.7K
01:19Electrophysiology of Normal Cardiac Rhythm
7.5K
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...
7.5K
01:31Regulation of Heart Rates
2.7K
The regulation of heart rate is a complex process controlled by the autonomic nervous system (ANS), hormonal influences, and intrinsic cardiac mechanisms. The ANS has two main components: the sympathetic nervous system (SNS) and the parasympathetic nervous system (PNS).
The SNS increases heart rate through the release of norepinephrine and epinephrine, which act on beta-1 adrenergic receptors in the heart. This action increases the rate of depolarization in the sinoatrial (SA) node, the heart's...
The SNS increases heart rate through the release of norepinephrine and epinephrine, which act on beta-1 adrenergic receptors in the heart. This action increases the rate of depolarization in the sinoatrial (SA) node, the heart's...
2.7K
01:29Pathophysiology of Cardiac Performance
889
Typical heart performance is influenced by heart rate, rhythm, myocardial contraction, and metabolism or blood flow. The cardiac muscle exhibits distinct electrophysiological features, including pacemaker activity and calcium channel control, which play a vital role in the heart's response to various drugs. The autonomic nervous system, comprising the sympathetic and parasympathetic branches, regulates heart rate. Sympathetic activation increases heart rate, while parasympathetic activation...
889
01:28Mechanism of Cardiac Arrhythmias
1.2K
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.
1.2K
01:13The Cardiac Cycle
92.0K
The heart beats rhythmically in a sequence called the cardiac cycle—a rapid coordination of contraction (systole) and relaxation (diastole).
The Process
Electrical signals—sent from the sinoatrial (SA) node in the right atrial wall to the atrioventricular (AV) node between the right atrium and right ventricle—cause both atria to simultaneously contract. When the signal reaches the AV node, it pauses for approximately a tenth of a second, allowing the atria to contract and...
The Process
Electrical signals—sent from the sinoatrial (SA) node in the right atrial wall to the atrioventricular (AV) node between the right atrium and right ventricle—cause both atria to simultaneously contract. When the signal reaches the AV node, it pauses for approximately a tenth of a second, allowing the atria to contract and...
92.0K