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Heart Disease Health Center

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Heart Block, Congenital

It is possible that the main title of the report Heart Block, Congenital is not the name you expected. Please check the synonyms listing to find the alternate name(s) and disorder subdivision(s) covered by this report.


  • Atrioventricular (AV) Block

Disorder Subdivisions

  • First Degree Congenital Heart Block
  • Second Degree Con. Heart Block (Wenckebach [Mobitz I]; Mobitz II; included)
  • Third Degree Congenital (Complete) Heart Block

General Discussion

Congenital heart block is characterized by interference with the transfer of the electrical nerve impulses (conduction) that regulate the normal, rhythmic, pumping action of the heart muscle (heart block). The severity of such conduction abnormalities varies among affected individuals.

The normal heart has four chambers. The two upper chambers are the atria and the two lower chambers are the ventricles. Within the right atrium of a normal heart is a natural pacemaker that initiates and controls the heartbeat. The electrical stimulus travels from the pacemaker (sinoatrial or SA node) to the ventricles along a very specific path consisting of conducting tissue and known as the AV (atrioventricular) node. As long as the electrical impulse is transmitted normally, the heart behaves normally.

If the transmission of the signal is impeded, the blocked transmission is known as a heart block or an AV block. If the heart block occurs in the fetus or newborn, the condition is known as congenital heart block. This condition has nothing at all to do with the flow of blood or with the blockage of a major or minor coronary artery. It is an electrical problem rather than a hydraulic one.

Heart blocks are categorized according to the degree of impairment of the patient. The categories are first, second and third degree heart block.


American Heart Association
7272 Greenville Avenue
Dallas, TX 75231
Tel: (214)784-7212
Fax: (214)784-1307
Tel: (800)242-8721

NIH/National Heart, Lung and Blood Institute
P.O. Box 30105
Bethesda, MD 20892-0105
Tel: (301)592-8573
Fax: (301)251-1223

Kids With Heart ~ National Association for Children's Heart Disorders, Inc.
1578 Careful Dr.
Green Bay, WI 54304
Tel: (920)498-0058
Fax: (920)498-0058
Tel: (800)538-5390

Little Hearts, Inc.
P.O. Box 171
110 Court Street, Suite 3A
Cromwell, CT 06416
Tel: (860)635-0006
Fax: (860)635-0006
Tel: (866)435-4673

Genetic and Rare Diseases (GARD) Information Center
PO Box 8126
Gaithersburg, MD 20898-8126
Tel: (301)251-4925
Fax: (301)251-4911
Tel: (888)205-2311
TDD: (888)205-3223

Fetal Hope Foundation
9786 South Holland Street
Littleton, CO 80127
Tel: (303)932-0553
Tel: (877)789-4673

For a Complete Report:

This is an abstract of a report from the National Organization for Rare Disorders (NORD). A copy of the complete report can be downloaded free from the NORD website for registered users. The complete report contains additional information including symptoms, causes, affected population, related disorders, standard and investigational therapies (if available), and references from medical literature. For a full-text version of this topic, go to and click on Rare Disease Database under "Rare Disease Information".

The information provided in this report is not intended for diagnostic purposes. It is provided for informational purposes only. NORD recommends that affected individuals seek the advice or counsel of their own personal physicians.

It is possible that the title of this topic is not the name you selected. Please check the Synonyms listing to find the alternate name(s) and Disorder Subdivision(s) covered by this report

This disease entry is based upon medical information available through the date at the end of the topic. Since NORD's resources are limited, it is not possible to keep every entry in the Rare Disease Database completely current and accurate. Please check with the agencies listed in the Resources section for the most current information about this disorder.

For additional information and assistance about rare disorders, please contact the National Organization for Rare Disorders at P.O. Box 1968, Danbury, CT 06813-1968; phone (203) 744-0100; web site or email

Last Updated: 4/12/2008
Copyright 1988, 1989, 1997, 1998, 2006 National Organization for Rare Disorders, Inc.

WebMD Medical Reference from the National Organization for Rare Disorders

Last Updated: May 28, 2015
This information is not intended to replace the advice of a doctor. Healthwise disclaims any liability for the decisions you make based on this information.

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