ECG changes in atrial fibrillation (AF)

Last reviewed 09/2020

The characteristic ECG changes seen in atrial fibrillation are:

  • no P waves - a irregular baseline is seen
  • irregular QRS complexes
  • normal QRS complexes
  • flutter-like waves may be seen transiently in V1

This condition is sometimes confused with atrial flutter; where the atrial rate is greater than 250 and there is a consequent atrio-ventricular block because the ventricles cannot match the atrial rate. In atrial flutter there may be a 'saw-tooth' appearance of the baseline. The QRS complexes are normal in atrial flutter.

Click here for ECG showing atrial fibrillation