Heart block · Watch
2nd Degree AV Block, Mobitz I (Wenckebach)
● Live · lead II25 mm/s · 10 mm/mV
II
10-second rhythm strip · count the boxes
RateAtrial normal; ventricular slightly slower
RegularityRegularly irregular (grouped beating)
P wavesNormal, regular P-P
PR intervalProgressively lengthens until a P fails to conduct
QRSNarrow
Key features
- 'Longer, longer, longer, drop, then you have a Wenckebach'
- R-R interval shortens before the dropped beat
- The PR after the pause is the shortest