About Bradycardia (Slow Heartbeat)

Bradycardia means your heart rhythm is slow or irregular. It can cause dizziness or shortness of breath during normal activities or light exercise. A pacemaker, like those pioneered by Medtronic, can regulate your heart's rhythm and let you get back to your normal pursuits.


Bradycardia is defined as a slow or irregular heart rhythm, usually less 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.


Common causes of bradycardia include:

  • A hereditary heart defect
  • Certain illnesses or heart medications
  • The natural ageing process
  • Scar tissue from a heart attack
  • Sick sinus syndrome (or 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


Symptoms of bradycardia include dizziness, fainting, extreme tiredness and shortness of breath.

Risk Factors

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 aged 65 or older
  • Have recently had heart surgery


Only your doctor can tell if you have bradycardia and how far the condition has progressed. To rule out or confirm the diagnosis of bradycardia, one or several of these diagnostic tests may be ordered depending upon the suspected heart rhythm problem:

  • Electrocardiogram (ECG)
  • Exercise ECG or stress test
  • Holter monitor (24 to 72 hour ECG)
  • Tilt table test
  • Electrophysiology (EP) study

Your doctor may also use a monitoring device to better understand the cause of unexplained fainting episodes. These monitoring devices include:

Information on this site should not be used as a substitute for talking with your doctor. Always talk with your doctor about diagnosis and treatment information.

Last updated: 18 Jan 2012

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