Which of the following is NOT a pattern of retrograde atrial depolarization in junctional escape rhythm?

Which of the following is NOT a pattern of retrograde atrial depolarization in junctional escape rhythm?

• A. Inverted P wave after the QRS complex
• B. Inverted P wave within the QRS complex
• C. Upright P wave after the QRS complex
• D. Inverted P wave before the QRS complex

Answer: (C)

In a junctional escape rhythm, the origin of impulse generation is typically from the AV node or junctional area, which can lead to distinct characteristics in the P wave morphology in relation to the QRS complex.

When assessing the P wave display in this scenario, several patterns can emerge based on the timing and direction of atrial depolarization relative to the ventricular depolarization represented by the QRS complex. In the specific context of inversion in the P wave, it is crucial to note that the atria can depolarize retrogradely (backwards) when the junctional focus takes over.

The option indicating an upright P wave after the QRS complex is a unique characteristic that generally doesn't fit into the patterns observed in junctional rhythms, where atrial depolarization is typically retrograde and thus would present as inverted waves if they appear at all. Inverted P waves may appear after the QRS, within the QRS, or even before the QRS, but not in an upright orientation when depolarization occurs retrogradely following a junctional escape rhythm.

Therefore, the option specifying an upright P wave after the QRS complex stands out as not being a pattern associated with retrograde atrial depolarization, distinguishing