Expert ECG Quiz 10 Answer

1. Normal sinus rhythm
2. Premature ventricular contractions
3. Atrial echo beats

Atrial echo beats (a.k.a. "reciprocal beats") occur when a premature ventricular complex is conducted backward (retrograde) across the AV node back to the atrium (a.k.a "ventriculoatrial conduction"). This requires two conduction pathways within the AV node (a.k.a. "dual AV nodal physiology") similar to what occurs in AVNRT.

The PVC conducts back to the atrium though the slow AV nodal pathway and then results in conduction back down the AV node to create the narrow-complex "echo beat". The P wave preceding the echo beat will have a junctional morphology, usually inverted in lead II (different than the sinus P wave).

Echo beats can also happen through the accessory pathway in a person with Wolff-Parkinson-White syndrome.

Related Topic Reviews: Premature Ventricular Contractions