Sinus Arrhythmia | Reference Guide

EKG Features

Rate: Normal (60-100 bpm) and rate may increase during inspiration
Rhythm: Irregular, varying with respiration
P Wave: Normal
PR Interval: Normal (0.12-0.20 sec)
QRS: Normal (0.06-0.10 sec)
Resembles Normal Sinus Rhythm with the distinction being the intervals from one cardiac complex to the next are changing as influenced by the patients respiratory pattern. Note the changing R to R Intervals.
Sinus arrhythmia is a cyclic variation on a sinus rhythm of more than 10% or 120ms due to respiratory breathing. It is common (and normal) in children. If the variation occurs independent of respiration in an adult, evaluate for sick sinus syndrome.
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