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Table 4. Definitions
Term Definition
Atrial fibrillation A supraventricular tachyarrhythmia with uncoordinated atrial
activation and ineffective atrial contraction
ECG characteristics include (a) irregular R-R intervals (when
atrioventricular [AV] conduction is present), (b) absence of
distinct P waves, and (c) irregular atrial activity also known as
fibrillatory waves. AF can be documented by 12 lead ECG, rhythm
strips, wearables, intracardiac electrograms, etc. but will always
require visual confirmation that the diagnosis is accurate.
Clinical AF With the increasing availability of wearable devices and other
continuous monitoring technologies, the distinction between
clinical and subclinical AF has become increasingly blurred thus
the writing group felt the term clinical AF has become less useful.
Yet, the term was kept since most of the evidence from randomized
trials that have led to guideline recommendations for the
treatment of AF refer to "clinical AF." ese trials required ECG
documentation of the arrhythmia for inclusion and a majority of
patients presented for clinical evaluation and/or therapy of the
arrhythmia.
Subclinical AF Subclinical AF refers to this arrhythmia identified in individuals
who do not have symptoms attributable to AF and in whom there
are no prior ECGs documenting AF.
is includes AF identified by implanted devices (pacemakers,
defibrillators, or implantable loop recorders) or wearable monitors.
Atrial high-rate
episodes (AHRE)
ese are defined as atrial events exceeding the programmed
detection rate limit set by the device. ese are recorded by
implanted devices but require visual inspection to confirm AF and
exclude other atrial arrhythmias, artifact or oversensing.
AF burden AF burden encompasses both frequency and duration and refers
to the amount of AF that an individual has. AF burden has
been defined differently across studies. For the purpose of this
guideline, AF burden will be defined as the durations of an episode
or as a percentage of AF duration during the monitoring period
depending on how it was defined in the individual studies.
First detected AF The first documentation of AF, regardless of prior symptoms
Paroxysmal AF AF that is intermittent and terminates within ≤7 days of onset
Persistent AF AF that is continuous and sustains for >7 days and requires
intervention. Of note, patients with persistent AF who with
therapy become paroxysmal should still be defined as persistent as
this reflects their original pattern and is a more useful to predict
outcomes and define substrate.
