What is Bradycardia? Slow Heart Rate


Bradycardia is a slow or irregular heart rhythm, usually fewer than 60 beats per minute. At this rate, the heart is not able to pump enough oxygen-rich blood to your body during normal activity or exercise. As a result, you may feel dizzy or have chronic lack of energy, shortness of breath, or even fainting spells.


Bradycardia can occur for several reasons. Common causes of bradycardia include:

  • Congenital heart disease (i.e., condition you were born with)
  • Certain side effects or heart medications
  • The natural aging process
  • Scar tissue from a heart attack
  • Sick sinus syndrome, also called sinus node dysfunction (the heart’s natural pacemaker not functioning correctly)
  • Heart block (the electrical impulse that travels from the upper to the lower chamber of the heart is irregular or blocked)


When your heart beats too slowly you may experience various symptoms. These symptoms including dizziness, fainting, chronic lack of energy, and shortness of breath, help your doctor access the severity of your heart condition and determine the appropriate treatment for you.

  • Dizziness
  • Chronic lack of energy
  • Shortness of breath
  • Fainting


Your risk of developing an abnormally slow heart rate (bradycardia) is greater if you:

  • Have certain types of heart disease
  • Are taking certain medicines
  • Are age 65 or older
  • Have recently had heart surgery


The treatment strategy for bradycardia is dependent on what is causing the slower than normal heart rate as well as the patient’s symptoms. If another medical problem, such as hypothyroidism, is causing a slow heart rate, treating it may indirectly affect bradycardia.

Treating these problems with new medicines, or adjusting the doses of the medicines you are currently taking, may restore a normal heartbeat.

If the damage within the heart’s electrical system is causing a slow heart rate, you may be eligible for an implantable heart device called a pacemaker.

Pacemakers are small devices that are implanted under the skin, most often below your collarbone on the left or right side of your chest, to help restore the heart’s rhythm.

By sending tiny electrical signals to the heart to increase the heart rate, a pacemaker can relieve the symptoms of bradycardia.