Cardiology In Critical Care
Normal Sinus Rhythem
Normal Sinus Rhythm
Impulses originate in the SA node regularly at a rate 60-100 per minute in adults and at faster rates in older children (90-110), small children (100-120) and infants (120-160). P waves upright in L2 and negative in AVR and of uniform size and contour from beat to beat. PR interval 0.12-0.20 sec and constant when A-V conduction normal; PR prolonged and/or variable when A-V block present. Each P followed by QRS with resulting P:QRS ratio 1:1 QRS ratio 1:1. QRS less than 0.11 sec or QRS wide and bizarre when bundle branch block present. RR intervals may be slightly irregular especially in the young and elderly.
|Rhythm||P Wave||PR Interval
|60 - 100 bpm||Regular||Before each QRS, identical||.12 to .20||< .12|
There have been Visitors to this website.
Return to Nurse Bob's™ Page