Ectopic Atrial Rhythm

Diagnostic criteria


  Heart rate is 60-100/minute.

  Every P wave is followed by a QRS complex.

  Since the impulse originates from an ectopic atrial focus the
P waves have a different configuration from

      that of the sinus wave.

  The recognization of differently shaped P waves in ectopic atrial rhythm may require the inspection of

      previous ECGs for comparison.

  Sometimes, the P waves may be negative in leads D2 and D3. In this case, the ectopic atrial rhythm is

      easy to diagnose. This rhythm is usually called as
coronary sinus rhythm or low atrial rhythm

      since the impulse is assumed to originate from the mouth of the coronary sinus.

  It can often be difficult to exactly localize the APC site from the surface ECG because the true P wave shape

      can be obscured by the T wave and the vagaries of the relationship between cardiac anatomy/position

      in the chest and the surface.




Ectopic Atrial Tachycardia

Diagnostic criteria


  Heart rate is > 100/minute.

  Other features are same as ectopic atrial rhythm.


Click here for left atrial rhythm






ECG 1. Ectopic atrial tachycardia in a patient with systemic arterial hypertension. P waves are negative in leads D2 and D3.

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ECG 2.
Ectopic atrial rhythm in a healthy boy of 14 years old. After 4 beats of ectopic atrial rhythm, the sinus rhythm takes over.
The R-R intervals of the
ectopic atrial rhythm are longer than the R-R intervals of the sinus rhythm.

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ECG 3.
Negative P waves in leads D2 and D3 show ectopic atrial rhythm.

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ECG 4a.
The negative P waves in leads II and III show ectopic atrial rhythm.

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ECG 4b. The ECG was recorded again a few minutes later. This time the rhythm is sinus.
In some patients, ectopic atrial rhyhtm may last for a very short time (seconds or minutes).

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ECG 5. Ectopic atrial rhythm in a 75 years-old man who had undergone coronary artery bypass surgery 2 years ago.
The ectopic atrial focus seems to be inferior and probably midline. His coronary arteries are normal.

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ECG 6. Atrial bigeminal rhythm in a 50 years-old man with normal coronary arteries.
The ectopic atrial focus is probably near the coronary sinus ostium.

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ECG 7. Above ECG is from a 64 years-old man with coronary artery disease, hypertension and aneurysm of the ascending aorta.
Runs of
ectopic atrial tachycardia with few sinus beats are seen.
P wave rate is about 115/minute.

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