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.

Rhythm P Wave PR Interval
(in seconds)
(in seconds)
> 100 bpm Regular Before each QRS, identical .12 to .20 < .12

There have been Visitors to this website.

Return to Nurse Bob's™ Page