saw-tooth ECG

Last reviewed 01/2018

These include:

  • if the P waves are about 300 per minute, and there is a 3:1 block, then the ECG will have a characteristic saw-tooth appearance
  • if atrial flutter is associated with a 2:1 block, P waves are difficult to recognise because of the superposition of the preceding T waves
  • flutter waves are most clearly seen in V1, II, III & aVF
  • an uncertain diagnosis can be confirmed if carotid sinus pressure results in an increase in the uncoupling of the atria and ventricles, revealing the flutter waves
  • always consider atrial flutter if a patient has a regular tachycardia of 150

Click here for an ECG example of atrial flutter