Bradycardia (Slow Heart Rate)

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What is Bradycardia?


Bradycardia is a type of heart rhythm disorder. It happens when someone’s heart rate falls below 50 beats per minute, which is slower than normal.

The heart’s electrical system controls when the heart contracts and pumps blood out to the body. If you have bradycardia, these signals are sluggish, or they become blocked in some way. 

Bradycardia can be caused by: 

  • Sinus node dysfunction: The heart’s natural pacemaker isn’t working properly.
  • Heart block: The electrical connection between the upper and the lower chambers of the heart doesn’t work as it’s supposed to. This causes the lower chamber that pumps blood out of the heart to beat slowly.

In some instances, a slow heart rate is normal. For example, being very athletic and physically fit can lead to the heart pumping more efficiently so it doesn’t need to beat as many times a minute to meet the body’s needs. Your heart also tends to naturally beat more slowly during sleep.

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Published: November 2018
Medical Reviewers: Mikhael F. El-Chami, MD, FACC; Martha Gulati, MD, MS, FACC, FAHA, FASPC

Infographic: Bradycardia

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