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Bradycardia

Cross section of heart showing left atrium and SA node and AV node in right atrium.

A slow heart rate is less than 60 beats a minute. That is called bradycardia. Bradycardia can be normal. Or it can be caused by medicines. Or it can be a sign of a disease. The slow heart rate may not be constant. It can come and go. It's a concern when it is very low, or when you have symptoms.

Symptoms

Symptoms of bradycardia are:

  • Dizziness or feeling lightheaded.

  • Weakness.

  • Trouble breathing.

  • Fainting.

  • Sleepiness.

  • More trouble exercising than normal because of tiredness (fatigue).

  • Confusion or trouble concentrating.

Causes

Bradycardia can have many causes. Some can be linked to your heart. But some may be linked to other things.

Nonheart-related causes:

  • Being older.

  • A side effect of certain medicines. These include beta-blockers, calcium channel blockers, digitalis, clonidine, lithium, and medicines to treat arrhythmias, such as amiodarone.

  • Health conditions, like low thyroid (hypothyroidism) and electrolyte disorder. Other examples are low body temperature (hypothermia) and sleep apnea.

  • Athletes, especially long-distance runners, may have a slow heart rate. This can be normal.

  • Brain injury, such as stroke or bleeding inside the brain.

Heart-related causes:

  • Coronary artery disease. This includes angina or past heart attack (acute myocardial infarction).

  • Heart valve disease.

  • Heart muscle disease (cardiomyopathy).

  • Congestive heart failure.

  • Sick sinus syndrome. This is when your heart's natural pacemaker is no longer working correctly.

  • Heart block. This is when your heart's natural electrical pathways no longer work correctly.

  • Diseases that enter the heart, such as sarcoid.

  • Heart infections.

Sometimes the cause for the arrhythmia can't be found.

Bradycardia that causes symptoms is sometimes reversible. When more severe bradycardia continues, you may need a pacemaker. Bradycardia may not cause symptoms. In this case, your health care provider may decide to watch it over time.

Home care

You can care for yourself at home:

  • Go back to your normal activities when you are feeling back to normal.

  • If you have any of the symptoms of bradycardia when you exert yourself, stop. Don't exert yourself. Wait until you have seen your health care provider for an assessment.

  • Work with your provider on any lifestyle changes you need. These might mean changing your diet, stopping smoking if you are a smoker, and starting an exercise program.

Follow-up care

Follow up with your health care provider as advised.

Call 911

Call 911 right away if:

  • You have chest pain.

  • You have chest pain that spreads to the shoulder, arm, neck, or back.

  • You have trouble breathing.

  • You have a slow heart rate with dizziness or lightheadedness.

  • You fainted or lost consciousness.

When to get medical care

Contact your health care provider if:

  • You have occasional weakness.

  • You feel dizzy or lightheaded.

  • You have abnormal trouble exercising.

Online Medical Reviewer: Stacey Wojcik MBA BSN RN
Online Medical Reviewer: Steven Kang MD
Date Last Reviewed: 1/1/2025
© 2000-2025 The StayWell Company, LLC. All rights reserved. This information is not intended as a substitute for professional medical care. Always follow your healthcare professional's instructions.
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