Diagnostic criteria

  Sinus node cannot produce an impulse at the expected time.

      On the ECG, this is seen as a long isoelectric line between the last QRS complex and

      the first P wave following the pause.

  In sinus arrest (sinus standstill),
the pause is NOT a multiple of the P-P interval that preceded

      the pause.

      In sinoatrial exit block, the pause is a multiple of the P-P interval that preceded the pause.

  If sinus arrest lasts long enough, then atrial, nodal or ventricular
escape beat (or rhythm) may be seen.



Causes

  Increased vagal tone

  Carotid sinus hypersensitivity

  Sleep apnea

  Sick sinus syndrome

  Myocardial ischemia / infarction



Links to similar ECGs

  Can J Rural Med 2012;17:110-113 - Answer.

  Int Arch Med 2012;5:11.

  Korean J Anesthesiol 2010;59(Suppl):S137-S140.

  BMJ Case Rep. 2011 Apr 13;2011. pii: bcr1120103519.





ECG 1. Sinus arrest in an adult. After the first 5
P waves no P waves follow at the expected time . The first P wave after the
sinus arrest
came lately.

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ECG 2. Sinus arrest in a 3 years old boy. Children have a higher resting heart rate when compared to adults. After the first 3
P waves there comes P wave at the expected time . The PP interval of the first P wave after the sinus arrest is NOT a
multiple of the P-P interval that preceded the pause (there is no sinoatrial exit block) Sinus arrest can be due to increased
vagal tone.

Pediatric cardiologist Dr. Mahmut Gokdemir has donated this ECG to our website.

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ECG 3a. The tracing above has been recorded 30 seconds before sinus arrest during a passive tilt table test.
Heart rate is 56/minute.


This ECG has been donated by Dorota Zysko.

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ECG 3b. The same patient's tracing 15 seconds before sinus arrest shows sinus bradycardia. Heart rate is 37/minute.


This ECG has been donated by Dorota Zysko.

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ECG 3c. The same patient during vasovagal syncope at the 24th minute of the passive tilt table test. The rhythm tracing shows
sinus arrest longer than 5 seconds. The resultant decrease in cerebral perfusion results in jerking movements which in turn
caused
artifacts .

This ECG has been donated by Dorota Zysko.

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ECG 3d. The heart rate increased to 44/minute 15 seconds after syncope.

This ECG has been donated by Dorota Zysko.

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ECG 4a. The ECG above belongs to a 74 years-old woman complaining of dizziness. The ECG is normal.
She has normal coronary arteries.

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ECG 4b. The same patient's ECG (limb leads) on a different day shows
sinus arrest .

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ECG 4c. The same patient's ECG (chest leads) on a different day shows
sinus arrest .

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ECG 4d. The above tracings are from the Holter recording of the same patient. This time, there are longer periods of sinus arrest.
In both tracings above,
the first 4 P waves are regular . Then a sinus arrest of 2.5 seconds occur in the upper tracing and
a nodal escape beat arises which has no P wave preceding it . In the bottom tracing the pause is longer this time (3.7 seconds).
Again the sinus arrest is long enough and
a nodal escape beat arises which has no P wave preceding it .

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