Understanding Third-Degree Heart Block
Heart block is a condition in which the electrical wiring system of the heart does not work properly. Sometimes it can result in a slow heartbeat that is either regular or irregular. This may cause symptoms.
With third-degree heart block, electrical signals are not relayed from the upper chambers of the heart (atria) to the lower chambers (ventricles). The signaling system in the lower chambers may take over as a backup, but this does not work well. People with third-degree heart block usually have a very slow heartbeat. Their heart does not do a good job of sending blood throughout the body. They usually have symptoms.
Third-degree heart block is sometimes called complete heart block.
What causes third-degree heart block?
Third-degree heart block may be caused by:
Damage to the heart from surgery
Damage to the heart muscle from a heart attack
Other types of heart disease that result in heart muscle damage
Heart valve disease
Other diseases, including rheumatic fever and sarcoidosis
In addition, some babies are born with heart block. Heart block may also run in families.
What are the symptoms of third-degree heart block?
Symptoms of third-degree heart block may include:
Lightheadedness, faintness, or dizziness
Shortness of breath
How is third-degree heart block treated?
Third-degree heart block is a serious condition that needs to be treated right away. Treatments for third-degree heart block include:
Taking medicines to increase the heart rate for the short-term (acutely)
Stopping medicines, if they are causing the heart block
Getting a pacemaker
What are the complications of third-degree heart block?
Third-degree heart block may cause a sudden loss of consciousness. It also may cause the heart to suddenly stop beating (sudden cardiac arrest).
When should I call my healthcare provider?
Call your healthcare provider right away if you have any of these:
Shortness of breath
Weakness, dizziness, or fainting
Unusual drowsiness or confusion
Pain that gets worse
Symptoms that don’t get better with treatment, or symptoms that get worse
March 21, 2017
Ferri F. Heart Block, Complete. In: Ferri F, editor. Ferri's Clinical Advisor 2016. Philadelphia: Elsevier; 2016. p. 568-9., Sauer WH. Congenital third degree (complete) atrioventricular block. Up To Date. October 26 ed: Up To Date; 2015. p. 10., Sauer WH. Etiology of atrioventricular block. Up To Date. October 30 ed: Up To Date; 2014. p. 9., Sauer WH. Third degree (complete) atrioventricular block. Up To Date. August 10 ed: Up To Date; 2015. p. 14.
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