What is the difference between normal sinus rhythm and atrial fibrillation?

Normal sinus rhythm shows regular, evenly spaced QRS complexes with a consistent P wave before each QRS, a heart rate of 60 to 100 beats per minute, and a regular rhythm. Atrial fibrillation shows an irregularly irregular rhythm with no identifiable P waves, replaced by a chaotic fibrillatory baseline. The ventricular rate varies and can be rapid, normal, or slow depending on conduction through the AV node.