ECG RHYTHM LAB

Multifocal Atrial Tachycardia

Multiple atrial foci create changing P waves at a rapid rate.

Generated six-second Lead II example · 120 bpm target rate · not a patient recording.

Typical rate

Above 100 bpm

Regularity

Irregularly irregular

P waves

At least three distinct shapes

PR interval

Varies

QRS

Usually narrow

What to look for

Identify three P-wave shapes and varying PR intervals, with an isoelectric baseline between P waves.

Show this rhythm

Sources and limitations