In AVNRT, where is the P wave typically observed relative to the QRS?

In AVNRT, where is the P wave typically observed relative to the QRS?

• A. Hidden under QRS
• B. Before QRS
• C. After QRS
• D. Absent

Answer: (A)

In AVNRT, the beat that depolarizes the ventricle does so through the AV node, while the atria are activated in the opposite (retrograde) direction. That means atrial depolarization happens while the ventricle is still depolarizing, so the P wave often occurs during the QRS complex and is therefore obscured. The result is a P wave that is typically not visible because it’s hidden under the QRS. Sometimes a small retrograde deflection can be seen after the QRS, but the common finding is that the P wave is not clearly observed.

In AVNRT, the beat that depolarizes the ventricle does so through the AV node, while the atria are activated in the opposite (retrograde) direction. That means atrial depolarization happens while the ventricle is still depolarizing, so the P wave often occurs during the QRS complex and is therefore obscured. The result is a P wave that is typically not visible because it’s hidden under the QRS. Sometimes a small retrograde deflection can be seen after the QRS, but the common finding is that the P wave is not clearly observed.