Welch Allyn Means ECG Physicians Manual for CP Series Electrocardiographs - User Manual - Manual (Page 52)

MEANS Physicians Manual
Welch Allyn
52
3.17 Group 14: Irregular rhythms with P/QRS > 1.0 and PR range

30 ms
The irregularity of the ventricular rhythm combined with the constancy of the PR interval and a
higher number of P waves than QRS complexes implies that either a second degree AV block
with constant preceding conduction times (Mobitz type II) or advanced AV block with varying
conduction ratios is present. In case of Mobitz type II AV block, the longer RR intervals will
most likely be sandwiched between shorter RR intervals. This is unlikely to occur in cases
with advanced AV block with varying conduction ratios.
Say: “atrial flutter”
if: shortest PP interval < 300 ms
Say:
“atrial tachycardia”
if: 300  shortest PP interval < 370 ms
Say:
“sinus tachycardia”
if: 370

shortest PP interval < 600 ms
Say:
“sinus rhythm”
if: shortest PP interval

600 ms
Say:
“with second degree AV block, type II (Mobitz II)”
if: varying RR intervals fulfilling Mobitz II criteria
Say:
“with second degree AV block at variable conduction ratio”
if: RR intervals not fulfilling Mobitz II criteria