ABSTRACT
Atrial fibrillation (AF) is a cardiac rhythm which has irregular undulations of the baseline
electrocardiogram (ECG) of varying amplitude, contour, and spacing known as fibrillation
waves, with the atrial rate between 350 and 600 beats per minute. The fibrillatory waves are
seen best in leads V1, II, III, and a ventricular fibrillation (VF). The fibrillation waves may
be large and coarse, or they may be fine with an almost flat ECG baseline. The ventricular
rate in AF is irregular unless complete atrioventricular (AV) block or dissociation is present.
The contour of the QRS complex in AF is normal unless there is prior bundle branch block,
an intraventricular conduction defect, or aberrant ventricular conduction.
