Electrical Conduction of the Heart Diagram

All 12 parts on the diagram

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The pathway of the signal 8

Sinoatrial node The pacemaker: it starts each signal and sets the rhythm.
Internodal pathways They carry the signal from the first node to the second.
Bachmann’s bundle It carries the signal across to the left atrium.
Atrioventricular node It delays the signal briefly before the ventricles receive it.
Atrioventricular bundle Also called the bundle of His; it splits into two branches.
Right bundle branch It carries the signal to the Purkinje fibers of the right ventricle.
Left bundle branch It carries the signal to the Purkinje fibers of the left ventricle.
Purkinje fibers A network under the lining that spreads the signal through the ventricles.

The four chambers 4

Right atrium It receives blood from the body; the sinoatrial node is here.
Left atrium It receives blood from the lungs.
Right ventricle The pump of the pulmonary circuit: it sends blood to the lungs.
Left ventricle The pump of the systemic circuit: it sends blood to the body.

How this list was compiled: Every name and detail line was checked on 2026-09-30 against the US National Cancer Institute SEER Training Modules, Physiology of the Heart, https://training.seer.cancer.gov/anatomy/cardiovascular/heart/physiology.html; TeachMeAnatomy, The Conducting System of the Heart, https://teachmeanatomy.info/thorax/organs/heart/conducting-system/; Kenhub, Conducting system of the heart, https://www.kenhub.com/en/library/anatomy/conducting-system-of-the-heart; Wikipedia, Cardiac conduction system, text only; and Henry Gray, Anatomy of the Human Body, 1918 (public domain), https://archive.org/details/anatomyofhumanbo00grayrich. Hints and detail lines are in our own words. Licence: own work

The drawing: Drawn for this site on 2026-09-30 from plain geometry. Own original drawing; nothing traced or copied. Licence: own work

How it works

This electrical conduction of the heart diagram shows a heart cut open from the front. The nodes, bundles and fibers that carry the signal for each beat are drawn over its four chambers.

Read the full guide

The pathway, in order

Parts 1 to 8 are numbered the way the signal travels: sinoatrial node, internodal pathways and Bachmann’s bundle across the atria, atrioventricular node, atrioventricular bundle, right and left bundle branches, Purkinje fibers. Parts 9 to 12 are the four chambers.

A heart diagram with nodes

As a heart diagram with nodes it shows both: the sinoatrial node where the superior vena cava meets the right atrium, and the atrioventricular node low between the atria. This diagram of the heart's electrical conduction system is also a conduction system of heart diagram to print blank and label by hand.

The heart’s right side is on the left of the drawing, as on a person facing you.
The nodes and bundles are drawn larger than life so that each can be found.

Questions and answers

What is the pathway of the cardiac conduction system?

Sinoatrial node, then across the atria by the internodal pathways and Bachmann’s bundle, atrioventricular node, atrioventricular bundle, right and left bundle branches, and last the Purkinje fibers in the ventricle walls.

Why is the sinoatrial node called the pacemaker?

It starts each signal by itself, 70 to 80 times a minute with no nerve telling it to, and so sets the basic rhythm of the heartbeat.

What does the atrioventricular node do?

It receives the signal from the atria and delays it briefly before passing it to the atrioventricular bundle, so the atria finish emptying into the ventricles before the ventricles contract.

Is the bundle of His the same as the atrioventricular bundle?

Yes. Bundle of His is another name for the atrioventricular bundle, the short stem that carries the signal from the atrioventricular node into the wall between the ventricles, where it splits into the right and left bundle branches.

Is this the key to “correctly label the pathway for the cardiac conduction system”?

That sentence is a publisher’s labeling activity. This page shows the same pathway on a drawing of our own, with parts 1 to 8 in the order the signal travels.