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Heart Block

What Is Heart Block?
Heart block is a problem that occurs with the heart's electrical system. This system controls the rate and rhythm of heartbeats. ("Rate" refers to the number of times your heart beats in a minute.)

With each heartbeat, an electrical signal spreads across the heart from the upper to the lower chambers. As it travels, the signal causes the heart to contract and pump blood. This process repeats with each new heartbeat.

Heart block occurs when the electrical signal is slowed or disrupted as it moves through the heart.

Heart block is a type of arrhythmia (ah-RITH-me-ah). An arrhythmia is any problem with the rate or rhythm of the heart.

You can be born with heart block or you can develop it. If you're born with it, it's called congenital (kon-JEN-i-tal) heart block. If it develops after birth, it's called acquired heart block.

Acquired heart block is more common. Damage to the heart muscle or to the heart's electrical system causes acquired heart block. Diseases, surgery, or medicines can cause this damage.

Congenital heart block may be found before or after a baby is born. If certain diseases occur during pregnancy, they may cause a baby to be born with heart block. Some congenital heart defects also may cause congenital heart block. Often, doctors don't know what causes these defects.

The three types of heart block are: first degree, second degree, and third degree. First degree is the least severe and third degree is the most severe. This is true for both congenital and acquired heart block.

Doctors use a test called an EKG (electrocardiogram) to help diagnose heart block. This test detects and records the heart's electrical activity. It records the data on a graph so the doctor can review it.

The symptoms and severity of heart block depend on which type you have. First-degree heart block rarely causes severe symptoms.

Second-degree heart block may result in the heart skipping a beat or beats. This type of heart block also can make you feel dizzy or faint.

Third-degree heart block limits the heart's ability to pump blood to the rest of the body. This type of heart block may cause fatigue (tiredness), dizziness, and fainting. Third-degree heart block requires prompt treatment, because it can be fatal.

A medical device called a pacemaker is used to treat third-degree heart block and some cases of second-degree heart block. This device uses electrical pulses to make the heart beat at a normal rate.