Lesson 13 of 21 · Rhythm Recognition

Atrial Rhythms

Atrial rhythms originate above the AV node and usually produce a narrow QRS. The baseline between beats is where the diagnosis hides.

01Premature atrial contractions

PAC: an early beat with a different-looking P wave and a narrow QRS.

Irregularly irregular, no P waves, fibrillatory baseline.

4:1 flutter: obvious sawtooth waves.

2:1 flutter at 150: flutter waves hide in the QRS and T.

Clinical pearl. A regular narrow-complex tachycardia at almost exactly 150 bpm is flutter with 2:1 block until proven otherwise.

Treat the underlying lung disease and replace magnesium and potassium. Cardioversion does not work.

MAT: ≥ 3 different P-wave morphologies, irregular, rate > 100. Classic in COPD.

Regular narrow tachycardia ~180 with no visible P waves.