Can You Recognize the Key to This Rhythm?
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This is a good lesson in wave form comparison. First of all, decide what
the basic rhythm is in this strip. What is the origin and what would you name it?
The origin is the Sinus Node and the name of the basic rhythm is
Sinus Tachycardia. Next, notice the atrial and ventricular rhythms are
both irregular. So you ask yourself, what is causing the irregularity?
As you go through the steps of rhythm interpretation, and you get to
the question of “do all P waves look the same”, your answer
should be no. The sinus P waves have a positive deflection, where as the
early beats have P waves with a negative deflection. These beats with
negative P waves and a shorter than normal PRI (or shorter then the sinus PRI),
are not coming from the sinus node but from the AV node. Beats coming from
the AV node are called Junctional beats; these beats are early, so they are
called Premature Junctional Contractions, or PJCs.
The correct interpretation for this rhythm is Sinus Tachycardia with PJCs.