Heart Disease Health Center

What is bradycardia?

Having bradycardia (say "bray-dee-KAR-dee-uh") means that your heart beats very slowly. For most people, a heart rate of 60 to 100 beats a minute while at rest is considered normal. If your heart beats less than 60 times a minute, it is slower than normal.

A slow heart rate can be normal and healthy. Or it could be a sign of a problem with the heart?s electrical system .

For some people, a slow heart rate does not cause any problems. It can be a sign of being very fit. Healthy young adults and athletes often have heart rates of less than 60 beats a minute.

In other people, bradycardia is a sign of a problem with the heart?s electrical system. It means that the heart's natural pacemaker is not working right or that the electrical pathways of the heart are disrupted. In severe forms of bradycardia, the heart beats so slowly that it does not pump enough blood to meet the body's needs. This can cause symptoms and can be life-threatening.

Men and women age 65 and older are most likely to develop a slow heart rate that needs treatment. As a person ages, the electrical system of the heart often does not function normally.

What causes bradycardia?

Bradycardia can be caused by:

• Changes in the heart that are the result of aging.
• Diseases that damage the heart's electrical system. These include coronary artery disease, heart attack, and infections such as endocarditis and myocarditis.
• Conditions that can slow electrical impulses through the heart. Examples include having a low thyroid level (hypothyroidism) or an electrolyte imbalance, such as too much potassium in the blood.
• Some medicines for treating heart problems or high blood pressure, such as beta-blockers, antiarrhythmics, and digoxin.

What are the symptoms?

A very slow heart rate may cause you to:

• Feel dizzy or lightheaded.
• Feel short of breath and find it harder to exercise.
• Feel tired.
• Have chest pain or a feeling that your heart is pounding or fluttering (palpitations).
• Feel confused or have trouble concentrating.
• Faint, if a slow heart rate causes a drop in blood pressure.

Some people don't have symptoms, or their symptoms are so mild that they think they are just part of getting older.

You can find out how fast your heart is beating by taking your pulse . If your heartbeat is slow or uneven, talk to your doctor.

How is bradycardia diagnosed?

Your doctor may be able to diagnose bradycardia by doing a physical exam, asking questions about your past health, and doing an electrocardiogram (EKG or ECG). An EKG measures the electrical signals that control heart rhythm.

But bradycardia often comes and goes, so a standard EKG done in the doctor?s office may not find it. An EKG can identify bradycardia only if you are actually having it during the test.