Table 1.

Definitions and types of atrial fibrillation

AF pattern	Definition
Clinical AF	Symptomatic ‘overt’ or asymptomatic ‘silent’ AF that is documented by surface ECG. The minimum duration of an ECG tracing of AF required to establish the diagnosis of clinical AF is ≥30 s, or a 12-lead ECG.10,16
First diagnosed AF	AF not diagnosed before, irrespective of its duration or presence/severity of AF-related symptoms.10
AHRE	Events fulfilling programmed or specified criteria for AHRE that are detected by CIEDs with an atrial lead. Need to be visually inspected.10
Subclinical AF	Includes AHRE confirmed to be AF, AFL or an AT, or AF episodes detected by insertable cardiac monitor or wearable monitor and visually confirmed.10

AHRE, atrial high-rate episode; AF, atrial fibrillation; ECG, electrocardiogram; AFL, atrial flutter; AT, atrial tachycardia; CIED, cardiac implantable electronic device; Based on 2020 ESC AFib Guidelines.¹⁰