Premature Atrial Contractions typically present as which feature?

• A. Early beats with different P waves and a compensatory pause
• B. Frequent early beats with no P waves
• C. Wide QRS after an early beat
• D. Early beats with similar P waves and a compensatory pause

Answer: (D)

Premature atrial contractions happen when atrial tissue fires a heartbeat earlier than expected. That premature beat comes with a P wave that accompanies the early QRS; the P wave is often visible and, in many cases, looks similar to the normal sinus P waves because the impulse originates in the atria in a way that produces atrial activation like the baseline rhythm. The QRS that follows is usually narrow, since ventricular conduction isn’t disrupted. The premature beat resets the timing enough that a pause occurs before the next regular beat, which is described as a compensatory pause in this context. In short, you see an early beat with a P wave that resembles the normal P waves, followed by a pause before the rhythm resumes.