Characterized by an irregular pause in the regular rhythm.
Occurs when there is a sudden absence of electrical activity in the SA node.
This results in a transient absence of a P-Wave on a rhythm strip.
One sinus impulse fails to form – sinus pause.
If more than one sinus impulse in a row fails to form – sinus arrest.
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1. Failure of the SA node to discharge an impulse.
2. Upsets the timing of the sinus node discharge, and the
underlying rhythm will not resume on time following the pause.
Rhythm: irregular – the underlying rhythm does not resume on time following the pause
Heart rate: can be normal, 60 - 100 or slow, 40 – 60
QRS: less than 0.10
P wave: only one precedes each QRS, all have same size, shape and deflection
PR interval: 0.12 - 0.20
Interpretation: Underlying rhythm with Sinus Arrest
1. If pauses are short, there may be no symptoms.
2. If pauses are long or frequent, patient may not tolerate and have
symptoms of hypotension, dizziness, syncope.
Treated only if accompanied by symptoms of hypoperfusion, treat as
symptomatic bradycardia.