Cardiology In Critical Care
Arrhythmia Recognition
Sinus Tachycardia (ST)
Sinus Tachycardia
Sinus Tachycardia
Impulses originate in the SA node at a rate 100-160/min in adults (and up to 200 or more in children). P upright in L2 and negative in AVR with identical or slightly different size and contour from beat to beat. At very rapid rates P superimposed on preceding T. When P recognizable, P:QRS ratio 1:1. Tachycardia usually appears and subsides gradually. Vagal stimulation produces gradual slowing which reverses when pressure is released. Exercise further increases the rate.
| Heart Rate |
Rhythm | P Wave | PR Interval (in seconds) |
QRS (in seconds) |
|---|---|---|---|---|
| > 100 bpm | Regular | Before each QRS, identical | .12 to .20 | < .12 |
There have
been
Visitors to this website.