Healthcare Library

Cardiac conduction system

A network of specialized muscle cells is found in the heart's walls. These muscle cells send signals to the rest of the heart muscle causing a contraction. This group of muscle cells is called the cardiac conduction system. The main parts of the system are the SA node, AV node, bundle of HIS, bundle branches, and Purkinje fibers. Let's follow a signal through the contraction process. The SA node starts the sequence by causing the atrial muscles to contract. That's why doctors sometimes call it the anatomical pacemaker. Next, the signal travels to the AV node, through the bundle of HIS, down the bundle branches, and through the Purkinje fibers, causing the ventricles to contract. This signal creates an electrical current that can be seen on a graph called an electrocardiogram, or EKG. Doctors use an EKG to see how well the cardiac conduction system works. Any changes on the EKG can mean serious problems.

Cardiac conduction system

Review Date: 5/16/2018

Reviewed By: Michael A. Chen, MD, PhD, Associate Professor of Medicine, Division of Cardiology, Harborview Medical Center, University of Washington Medical School, Seattle, WA. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.

The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed medical professional should be consulted for diagnosis and treatment of any and all medical conditions. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites. © 1997- A.D.A.M., a business unit of Ebix, Inc. Any duplication or distribution of the information contained herein is strictly prohibited.

Animations

Browse All

Videos

Browse All

In-Depth Animations

Browse All

A.D.A.M. content is best viewed in IE9 or above, Firefox and Google Chrome browser.
Content is best viewed in IE9 or above, Firefox and Google Chrome browser.

ways to give

view all

news room

view all

healthcare library

view all
Event Calendar

Hunterdon Healthcare offers an array of educational events, including childbirth, healthy living and fitness classes.

LEARN MORE
Health and Wellness Centers

Where health and fitness meet to help you stay healthy at every age.

LEARN MORE
Heart & Vascular

Heart and Vascular Services Department brings world-class cardiovascular care to our community.

LEARN MORE