Sinus Arrest - Course # 313-8
- Sinus Arrest occurs when there is a sudden absence of electrical activity initiated by the SA node. This results in a pause in the electrical activity seen on the tracing. Remember, no electrical activity = no depolarization and contraction. Hence, a drop in blood pressure.
- The longer the pause, the further the blood pressure will drop.
- A pause of six-seconds is considered a medical emergency and emergency procedures must be initiated.
- The rhythm typically will demonstrate constant R to R intervals prior to and following the pause. This pause results in the rhythm tracing presenting as irregular.
- It is important to measure the duration of the pause and report this information along with the frequency of the pauses if there are more than one.
- The pause is measured by placing your caliper tips on the last R wave just prior to the pause and the R wave immediately following the pause. Count the number of small boxes and multiply by 0.04 second. This will be reported as part of the interpretation.
Sinus Arrest - Practice Strip
- Analyze this tracing using the five steps of rhythm analysis.
- Compare your answers with the answers on the next slide.
Practice Strip - Answers
- Rhythm: Irregular
- Rate: 40 bpm
- P wave: upright and uniform
- PR interval: 0.16 sec
- QRS: 0.10 sec
- Interpretation: Sinus Arrest, 3.52 second pause
313 Sinus Arrest - Course # 313-8