Pathophysiology
         
Atrial Fibrillation        

An irregularly irregular rhythm in which P waves are NOT present. R-R intervals are variable. Absence of a clear isoelectric baseline. QRS complexes are often < 120 ms unless there is a pre-existing bundle branch block, accessory pathway, or rate related aberrant conduction. Fibrillatory “f”waves are often present and can be either fine (amplitude < 0.5mm) or coarse (amplitude >0.5mm). Be aware that coarse “f” waves can sometimes mimic p-waves and be misinterpreted.

Rhythm Strip
Atrial Fibrillation Rhythm Strip

Atrial fibrillation with slow ventricular response (33 BPM).

12 Lead EKG
Atrial Fibrillation 12 Lead EKG
Rhythm Strip
Atrial Fibrillation Rhythm Strip_fig2

Atrial fibrillation with fast ventricular response (148 BPM).

12 Lead EKG
Atrial Fibrillation 12 Lead EKG_fig2
Rhythm Strip
Atrial Fibrillation Rhythm Strip_fig3

Atrial fibrillation with controlled ventricular response (76 BPM)

12 Lead EKG
Atrial Fibrillation 12 Lead EKG_fig3