The heart is comprised of four chambers: two upper chambers (atria) and two lower chambers (ventricles). The sinoatrial (SA) node, located near the top of the right atrium, produces electrical signals that are sent to the atrioventricular (AV) node. The AV node then sends the signals to the ventricles, which are the primary pumping chambers of the heart. When the heart is functioning well, the electrical signals are transmitted smoothly from the atria to the ventricles, causing rhythmic muscle contractions that pump blood to the rest of the body.
Heart block occurs when the electrical signals from the sinoatrial node are too slow. A heart block does not mean that blood is being blocked from the heart.
There are three types of heart block, ranging from mild to serious:
Third-degree heart block is extremely serious and requires immediate care from your doctor. First- and second-degree heart block should be diagnosed by your physician, who will help you determine the best course of treatment, if any.
Heart block often occurs when there is underlying heart disease. The causes of heart block include:
The following factors increase your chance of developing heart block. If you have any of these risk factors, tell your doctor:
If you experience any of these symptoms, do not assume it is due to heart block. These symptoms may be caused by other, less serious health conditions. If you experience any one of them, see your physician.
Your doctor will ask about your symptoms and medical history, and perform a physical exam. He or she may also refer you to a cardiologist or arrhythmia specialist.
Tests may include the following:
The course of treatment will depend on the type of heart block you have. Generally, treatment is not necessary for first-degree heart block.
Talk with your doctor about the best treatment plan for you. Treatment options include the following:
If you are diagnosed with heart block, follow your doctor's instructions .
To help reduce your chances of getting heart block, take the following steps:
RESOURCES:
American College of Cardiology
http://www.acc.org
American Heart Association
http://www.americanheart.org
Heart Rhythm Society
http://www.hrsonline.org
CANADIAN RESOURCES:
Canadian Cardiovascular Society
http://www.ccs.ca/home/index_e.aspx
Heart and Stroke Foundation of Canada
http://ww2.heartandstroke.ca
References:
Fauci AS, Braunwald E, Isselbacker KJ, et al. Harrison’s Principles of Internal Medicine . 14th ed. New York, NY: McGraw-Hill; 1998.
Gregoratos G. Indications and recommendations for pacemaker therapy. Am Fam Physician . 2005;71(8):1563-1570. Also available at: http://www.aafp.org/afp/20050415/1563.pdf . Accessed on August 20, 2005.
Heart block. American Heart Association website. Available at: http://www.americanheart.org/presenter.jhtml?identifier=4611 . Accessed on August 20, 2005.
Heart block. Heart Rhythm Society website. Available at: http://www.hrspatients.org/patients/heart_disorders/heart_block.asp . Accessed on August 20, 2005.
Last reviewed November 2008 by Michael J. Fucci, DO
Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.
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