The diagnosis of AF requires rhythm documentation using an electrocardiogram (ECG) showing the typical pattern of AF: Absolutely irregular RR intervals and no discernible, distinct P waves. ECG-documented AF was the entry criterion in trials forming the evidence for these guidelines. By accepted convention, an episode lasting at least 30 s is diagnostic. Individuals with AF may be symptomatic or asymptomatic (‘silent AF’)
The diagnosis of AF in a patient is based on the patient’s clinical history and physical examination and is confirmed by ECG, ambulatory rhythm monitoring (eg, telemetry, Holter monitor, event recorders), implanted loop recorders, pacemak- ers or defibrillators, or, in rare cases, by electrophysiological study.