A report on Atrioventricular node

Image showing the conduction system of the heart. The AV node is labelled 2.
Isolated heart conduction system showing atrioventricular node

Part of the electrical conduction system of the heart.

- Atrioventricular node
Image showing the conduction system of the heart. The AV node is labelled 2.

11 related topics with Alpha

Overall

Heart

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Muscular organ in most animals.

Muscular organ in most animals.

Human heart during an autopsy
Computer-generated animation of a beating human heart
The human heart is in the middle of the thorax, with its apex pointing to the left.
Heart being dissected showing right and left ventricles, from above
Frontal section showing papillary muscles attached to the tricuspid valve on the right and to the mitral valve on the left via chordae tendineae.
Layers of the heart wall, including visceral and parietal pericardium
The swirling pattern of myocardium helps the heart pump effectively
Arterial supply to the heart (red), with other areas labelled (blue).
Autonomic innervation of the heart
Development of the human heart during the first eight weeks (top) and the formation of the heart chambers (bottom). In this figure, the blue and red colors represent blood inflow and outflow (not venous and arterial blood). Initially, all venous blood flows from the tail/atria to the ventricles/head, a very different pattern from that of an adult.
Blood flow through the valves
The cardiac cycle as correlated to the ECG
The x-axis reflects time with a recording of the heart sounds. The y-axis represents pressure.
Transmission of a cardiac action potential through the heart's conduction system
Conduction system of the heart
The prepotential is due to a slow influx of sodium ions until the threshold is reached followed by a rapid depolarization and repolarization. The prepotential accounts for the membrane reaching threshold and initiates the spontaneous depolarization and contraction of the cell; there is no resting potential.
3D echocardiogram showing the mitral valve (right), tricuspid and mitral valves (top left) and aortic valve (top right). The closure of the heart valves causes the heart sounds.
Cardiac cycle shown against ECG
Heart and its blood vessels, by Leonardo da Vinci, 15th century
Animated heart
Elize Ryd making a heart sign at a concert in 2018
The tube-like heart (green) of the mosquito Anopheles gambiae extends horizontally across the body, interlinked with the diamond-shaped wing muscles (also green) and surrounded by pericardial cells (red). Blue depicts cell nuclei.
Basic arthropod body structure – heart shown in red
The human heart viewed from the front
The human heart viewed from behind
The coronary circulation
The human heart viewed from the front and from behind
Frontal section of the human heart
An anatomical specimen of the heart
Heart illustration with circulatory system
Animated Heart 3d Model Rendered in Computer

These generate a current that causes the heart to contract, traveling through the atrioventricular node and along the conduction system of the heart.

Heart; conduction system. 1. SA node. 2. AV node. 3. Bundle of His. 8. Septum

Electrical conduction system of the heart

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The electrical conduction system of the heart transmits signals generated usually by the sinoatrial node in the heart to cause contraction of the heart muscle.

The electrical conduction system of the heart transmits signals generated usually by the sinoatrial node in the heart to cause contraction of the heart muscle.

Heart; conduction system. 1. SA node. 2. AV node. 3. Bundle of His. 8. Septum
Overview of the system of electrical conduction which maintains the rhythmical contraction of the heart
Principle of ECG formation. Note that the red lines represent the depolarization wave, not bloodflow.
Different wave shapes generated by different parts of the heart's action potential

The pacemaking signal generated in the sinoatrial node travels through the right atrium to the atrioventricular node, along the Bundle of His and through bundle branches to cause contraction of the heart muscle.

Ventricular fibrillation (VF) showing disorganized electrical activity producing a spiked tracing on an electrocardiogram (ECG)

Arrhythmia

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Too fast or too slow.

Too fast or too slow.

Ventricular fibrillation (VF) showing disorganized electrical activity producing a spiked tracing on an electrocardiogram (ECG)
Broad classification of arrhythmias according to region of heart required to sustain the rhythm
Normal sinus rhythm, with solid black arrows pointing to normal P waves representative of normal sinus node function, followed by a pause in sinus node activity (resulting in a transient loss of heartbeats). Note that the P wave that disrupts the pause (indicated by the dashed arrow) does not look like the previous (normal) P waves – this last P wave is arising from a different part of the atrium, representing an escape rhythm.

The impulse initially causes both atria to contract, then activates the atrioventricular node (AV node), which is normally the only electrical connection between the atria and the ventricles (main pumping chambers).

Leads aVL and aVF of an electrocardiogram showing atrial fibrillation. There are irregular intervals between heart beats. No P waves are seen and there is an erratic baseline between QRS complexes. The heart rate is about 125 beats per minute.

Atrial fibrillation

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Abnormal heart rhythm (arrhythmia) characterized by rapid and irregular beating of the atrial chambers of the heart.

Abnormal heart rhythm (arrhythmia) characterized by rapid and irregular beating of the atrial chambers of the heart.

Leads aVL and aVF of an electrocardiogram showing atrial fibrillation. There are irregular intervals between heart beats. No P waves are seen and there is an erratic baseline between QRS complexes. The heart rate is about 125 beats per minute.
Normal rhythm tracing (top) Atrial fibrillation (bottom)
How a stroke can occur during atrial fibrillation
Non-modifiable risk factors (top left box) and modifiable risk factors (bottom left box) for atrial fibrillation. The main outcomes of atrial fibrillation are in the right box. BMI=Body Mass Index.
A 12-lead ECG showing atrial fibrillation at approximately 132 beats per minute
Diagram of normal sinus rhythm as seen on ECG. In atrial fibrillation the P waves, which represent depolarization of the top of the heart, are absent.
ECG of atrial fibrillation (top) and normal sinus rhythm (bottom). The purple arrow indicates a P wave, which is lost in atrial fibrillation.
3D Medical Animation still shot of Left Atrial Appendage Occlusion

These disorganized waves conduct intermittently through the atrioventricular node, leading to irregular activation of the ventricles that generate the heartbeat.

An example of an ECG tracing typical of uncommon AV nodal reentrant tachycardia. Highlighted in yellow is the P wave that falls after the QRS complex.

AV nodal reentrant tachycardia

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Type of abnormal fast heart rhythm.

Type of abnormal fast heart rhythm.

An example of an ECG tracing typical of uncommon AV nodal reentrant tachycardia. Highlighted in yellow is the P wave that falls after the QRS complex.
During typical AVNRT, electrical impulses travel down the slow pathway of the AV node and back up the fast pathway.
AVNRT termination following administration of adenosine

AVNRT occurs when a reentrant circuit forms within or just next to the atrioventricular node.

Atrial flutter with varying A-V conduction (5:1 and 4:1)

Atrial flutter

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Common abnormal heart rhythm that starts in the atrial chambers of the heart.

Common abnormal heart rhythm that starts in the atrial chambers of the heart.

Atrial flutter with varying A-V conduction (5:1 and 4:1)
Type I atrial flutter, counterclockwise rotation with 3:1 and 4:1 AV nodal block.
Atrial flutter with a two to one block. Note the P waves hiding in the T waves in leads V1 and V2

Impulses from the atria are conducted to the ventricles through the atrio-ventricular node (AV node).

Sinoatrial node shown at 1. The rest of the conduction system of the heart is shown in blue.

Sinoatrial node

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Group of cells known as pacemaker cells, located in the wall of the right atrium of the heart.

Group of cells known as pacemaker cells, located in the wall of the right atrium of the heart.

Sinoatrial node shown at 1. The rest of the conduction system of the heart is shown in blue.
Figure 2: Low magnification stained image of the SA node (center-right on image) and its surrounding tissue. The SA node surrounds the sinoatrial nodal artery, seen as the open lumen. Cardiac muscle cells of the right atrium can be seen to the left of the node, and fat tissue to the right.
Figure 3: Sinoatrial node action potential waveform, outlining major ion currents involved (downward deflection indicates ions moving into the cell, upwards deflection indicates ions flowing out of the cell).
Schematic representation of the atrioventricular bundle

Other cells within the heart (including the Purkinje fibers and atrioventricular node) can also initiate action potentials; however, they do so at a slower rate and therefore, if the SA node is functioning properly, its action potentials usually override those that would be produced by other tissues.

Sternocostal surface of heart.

Atrioventricular nodal branch

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Sternocostal surface of heart.

The atrioventricular nodal branch is a coronary artery that feeds the atrioventricular node, necessary for the excitation of the ventricles.

Representative electrocardiogram recordings of the different degrees of heart block

Atrioventricular block

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Type of heart block that occurs when the electrical signal traveling from the atria, or the upper chambers of the heart, to ventricles, or the lower chambers of the heart, is impaired.

Type of heart block that occurs when the electrical signal traveling from the atria, or the upper chambers of the heart, to ventricles, or the lower chambers of the heart, is impaired.

Representative electrocardiogram recordings of the different degrees of heart block
Electrical conduction pathway of the heart.
Normal ECG tracing for a single contraction of the heart.
ECG tracing in relation to normal depolarization and contraction of the heart. Red tracing indicates pathway of electrical depolarization. Blue tracing indicates resulting ECG tracing.

The signal travels from the SA node to the ventricles through the atrioventricular node (AV node).

Koch's triangle

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Anatomical area located in the superficial paraseptal endocardium of the right atrium, which its boundaries are the coronary sinus orifice, tendon of Todaro, and septal leaflet of the right atrioventricular valve.

Anatomical area located in the superficial paraseptal endocardium of the right atrium, which its boundaries are the coronary sinus orifice, tendon of Todaro, and septal leaflet of the right atrioventricular valve.

It is anatomically significant because the atrioventricular node is located at the apex of the triangle.