ECG: Atrial Fibrillation

An ECG strip shows the presence of atrial fibrillation, which involves rapid uncoordinated contraction of the atria. Atrial fibrillation is indicated by a very rapid (350 to 450 beats per minute) rate and an erratic rhythm. The ventricular (QRS) rate is normal. A normal ECG strip is shown at the bottom for comparison.

(From D Dubin, Rapid Interpretation of EKGs, 1996, Cover Inc., p. 95, 160; with permission.)