Online ACLS Course

Chapter 15 : Unstable Tachycardia

Tachycardia is when the heart rate or rhythm is too fast (>100 beats/min).  Increase in heart rate causes less blood to be pumped through the systemic and pulmonary systems. Low blood flow will cause less oxygen to flow to the heart and brain and less oxygen to the heart can lead to Ischemia and MI.   Unstable tachycardia is when the heart rate is too fast causing unstable conditions and symptoms caused by >150bpm.  Some symptoms may include:

  • Hypotension
  • Altered mental status
  • Shock
  • Chest pain or discomfort
  • Acute heart failure

The rhythms for unstable tachycardia include:

  • Atrial fibrillation
  • Atrial flutter
  • SVT
  • Monomorphic VT
  • Polymorphic VT
  • Wide-Complex tachycardia of uncertain type
Video Demonstration

Unstable Tachycardia

Atrial fibrillation is when the heart beats do not occur at the same intervals.  It is known as the quivering of the muscles and involves both the atriums of the heart.

atrial fibrillation

Atrial flutter is abnormal heart rhythm causing fast irregular heartbeat.  Starts in the atrium and can lead to atrial fibrillation. Usually has a ‘saw-toothed’ appearance.

atrial flutter

Supraventricular Tachycardia (SVT) is a rapid and narrow heartbeat that starts in the atria or AV node.