Cardiac arrhythmias

Cardiac dysrhythmia is an abnormal heart beat:

• rhythm may be irregular in its pacing or the heart rate may be low or high
  • some dysrhythmias are potentially life threatening while other dysrhythmias (such as sinus arrhythmia) are a normal variant

Heart rate and origin (atria or ventricles) are used to help classify cardiac dysrhythmias.

Tachycardia is a fast (over 100 beats per minute) heart rhythm

• tachycardias can originate in the atria or ventricles.

Dysrhythmias that originate in the atria are termed supraventricular dysrhythmias (supraventricular means above the ventricles).

• these dysrhythmias include:
  • atrial flutter
  • atrial fibrillation
  • paroxysmal supraventricular tachycardia
  • atrial tachycarda
  • sinus tachycardia

Ventricular dysrhythmias originate in the ventricles and include:

• ventricular fibrillation
• ventricular ectopics
• ventricular tachycardia

Bradycardia is a slow (under 60 beats per minute) heart rhythm.

Bradyarrhythmias are slow heart rhythms arising from disease in the cardiac electrical conduction system.

Bradyarrhythmias include:

• sinus bradycardia
• atrioventricular conduction block
• sick sinus syndrome

A premature beat is an extra beat, occurring earlier than normal - it is termed an ectopic beat and may be atrial or ventricular in origin

• despite being an extra beat, patients may indicate feeling a "skipped beat"