Heart block is a problem in the electrical signals in the heart.
Normally, the heart beat starts in an area in the top chambers of the heart (atria). This area is the heart's pacemaker. The electrical signals travel to the lower chambers of the heart (ventricles). This keeps the heart beat steady and regular.
Heart block occurs when the electrical signal is slowed down or does not reach the bottom chambers of the heart. Your heart may beat slowly, or it may skip beats. Heart block may resolve on its own, or it may be permanent and require treatment.
There are three degrees of heart block. First-degree heart block is the mildest type and third-degree is the most severe.
First-degree heart block:
Second-degree heart block:
Third-degree heart block:
AV Block; Arrhythmia; First-degree heart block; Second-degree heart block; Mobitz type 1; Wenckebach's block; Mobitz type II; Third-degree heart block
Heart block may be caused by:
You may have heart block because you were born with it. You are more at risk for this if:
Talk to your health care provider about your symptoms. The symptoms are different for first, second, and third-degree heart block.
You may not have any symptoms for first-degree heart block. You may not know you have heart block until it shows up on a test called an electrocardiogram (ECG).
If you have second-degree or third-degree heart block, symptoms may include:
Exams and Tests
Your health care provider will most likely send you to a heart doctor (cardiologist) to check for heart block.
The cardiologist will talk to you about your medical history and the medicines you are taking. The cardiologist will also:
The treatment for heart block depends the type of heart block you have and the cause.
If you do not have serious symptoms and have a milder type of heart block, you will most likely need to:
If you have second- or third-degree heart block, you may need a pacemaker to help your heart beat regularly.
With regular monitoring and treatment, you should be able to keep up most of all of your usual activities.
Heart block may increase the risk for:
If you have a pacemaker, you cannot be near magnetic fields. You need to let people know that you have a pacemaker.
When to Contact a Medical Professional
Call your health care provider if you feel:
Call your provider if you have signs of heart failure:
American Heart Association. Conduction disorders. October, 2012. www.heart.org/HEARTORG/Conditions/Arrhythmia/AboutArrhythmia/Conduction-Disorders_UCM_302046_Article.jsp. Accessed January 8, 2015.
Olgin JE, Zipes DP. Specific arrhythmias. In: Mann DL, Zipes DP, Libby P, Bonow RO, Braunwald E, eds. Braunwald's Heart Disease: A Textbook of Cardiovascular Medicine. 10th ed. Philadelphia, PA: Elsevier Saunders; 2015:chap 37.
Review Date: 5/4/2015
Reviewed By: Larry A. Weinrauch MD, Assistant Professor of Medicine, Harvard Medical School, Cardiovascular Disease and Clinical Outcomes Research, Watertown, MA. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, 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. Call 911 for all medical emergencies. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites. © 1997- A.D.A.M., Inc. Any duplication or distribution of the information contained herein is strictly prohibited.