but PR interval will be short (< 0.12 ms). If the pacemaker occurs at the junction, the P wave and QRS complex may be exactly overlying and you may not be able to identify any P waves at all.

These ECG voltage attenuations are of extracardiac mechanism, and impact the amplitude of QRS complexes, P-waves, and T-waves, occasionally resulting also in shortening of the QRS complex and QT ...

Looking closely at the last part of the QRS complex in leads V1 and V2, P waves can be seen. This is considered a "short RP tachycardia" and is from AVNRT. Adenosine, carotid massage or vagal ...