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Heart Rhythm Disorders: Abnormal Heart Rhythms

Normal heart rhythm

A normal heart beat is caused by an electrical signal running from top to bottom in the heart. This electrical signal tells the heart when and how to beat. The normal electrical signal:

  • Starts at the top of the heart (the sinus node)
  • Spreads its message across both upper chambers of the heart (the right and left atria)
  • Travels through the gateway between the upper and lower chambers of the heart (the AV node)
  • Reaches the bottom of the heart
  • Spreads the signal to both lower chambers (the right and left ventricles)

When an electrical signal follows this normal pathway, the heart beats in a regular, organized rhythm. It maintains the teamwork between the upper and lower heart chambers. Normally, the upper chambers beat first, followed by the lower chambers. The normal heart rate is about 60 to 100 beats per minute.

Abnormal heart rhythms

Abnormal heart rhythms involve the heart’s electrical system and sometimes its structure. Both children and adults can have abnormal rhythms. Some abnormal rhythms are inherited. Learn more about the types of abnormal heart rhythms, risks, symptoms and treatment.

Patient education – video links

How The Heart Works (ACC)  
Common Heart Problems (HRS) Select Electrical System and other topics from the dropdown menu.

Patient education – narrative information

The Heart's Electrical System (HRS)
The Normal Heart (HRS)