Every 2nd P-wave doesn't produce a QRS complex (in fact, non-conducting P waves are superimposed on the preceding T wave)
QRS is wide
Mobitz I (aka Wenckebach) is where the PR interval increases until a P wave isnt conducted, but then resumes where it started. These are usually benign.
Mobitz II is where the PR interval is fixed, but P waves don't conduct in an (often) fixed ratio. These are not benign and need intervention (with a PPM)...and atropine often makes it worse!
So which one is this one?
A tricky (not trick) question!
It can be hard to tell with a 2:1 block (there isn't enough PR intervals to tell if they're getting longer or not)
Patient history and QRS are the main differentiators:
1. Patient History: Mobitz II is not benign, so a history of syncope is telling
2. QRS: 75% of blocks from Mobitz II are from pre-existing LBBB or bifasicular block - but the caveat to this is that 25% will have a normal QRS and that someone with Mobitz I may have a pre-existing bundle branch block!
Regarding the 2nd degree heart block - erring on the side of caution, she deserves a period of telemetry to try and capture a longer segment prior to dropping a beat (fixed ratios for Mobitz I or II often drift transiently into 3:1)