Normal sinus rhythm is characterized by which ECG feature?

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Multiple Choice

Normal sinus rhythm is characterized by which ECG feature?

In normal sinus rhythm, atrial activation starts at the sinus node and the atrial depolarization produces a normal, upright P wave that precedes every QRS complex. This consistent, properly shaped P wave is the hallmark of a sinus-origin rhythm, typically with a normal PR interval as well. So the best descriptor is a normal P wave: it shows that atrial depolarization is occurring from the SA node and pacing the rhythm correctly. If the P waves were inverted, that would suggest atrial activation coming from a non-sinus source. Absent P waves points to rhythms where atrial depolarization isn’t seen (such as junctional rhythms or atrial fibrillation). A biphasic P wave isn’t the defining feature of normal sinus rhythm.

In normal sinus rhythm, atrial activation starts at the sinus node and the atrial depolarization produces a normal, upright P wave that precedes every QRS complex. This consistent, properly shaped P wave is the hallmark of a sinus-origin rhythm, typically with a normal PR interval as well. So the best descriptor is a normal P wave: it shows that atrial depolarization is occurring from the SA node and pacing the rhythm correctly.

If the P waves were inverted, that would suggest atrial activation coming from a non-sinus source. Absent P waves points to rhythms where atrial depolarization isn’t seen (such as junctional rhythms or atrial fibrillation). A biphasic P wave isn’t the defining feature of normal sinus rhythm.

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