Fibrillation atriale · ECG

Definition

Atrial fibrillation is disorganised atrial activity; a typical ECG shows irregular RR intervals.

Examination or reading method

Check calibration and artefacts; assess several leads, atrial activity, RR intervals and QRS width.

Morphological description

Describe absent repeating P waves, possible fibrillatory activity and ventricular rate.

Causes and diagnostic direction

Associated conditions include hypertension, cardiac or valve disease, thyroid disorders, alcohol exposure and acute illness.

Differential diagnoses

Variable-conduction flutter, ectopy and multifocal atrial tachycardia may be irregular; seek organised atrial activity.

Associated findings

Assess palpitations, dyspnoea, presyncope and cardiac disease; ECG confirmation and clinical assessment guide investigation.

Red flags

Hypotension, ischaemic pain, respiratory distress or acute neurological deficit requires urgent assessment.

Pitfalls and limitations

Artefact may mimic fibrillation; an irregular pulse or automatic alert cannot replace ECG confirmation.

Take-home message

Recognise irregularity and absent organised atrial activity, then confirm the reading and assess the patient.

Sources

Documentary review: 2026-10-15

Atrial fibrillation · ECG