Diagnostic criteria

  Heart rate is > 100/minute and irregular.

      This feature differentiates it from the wandering atrial pacemaker.

  Every P wave is followed by a QRS complex.

  Since the impulses originate from multiple ectopic atrial foci,

      there are P waves with
at least 3 different configurations.

  Since the impulses originate from multiple ectopic atrial foci the P-P, PR ve R-R intervals
differ.

  MAT is usually misdiagnosed as atrial fibrillation since P waves with different shapes may be

      mistaken for fibrillation waves.

  Usually observed in patients with severe respiratory failure or in intensive care unit patients.





ECG 1. Multifocal atrial tachycardia. Heart rate is above 100/minute. There are P waves with at least 3 different shapes.

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ECG 2. This ECG is from a patient with chronic obstructive pulmonary disease (COPD). The presence of
P waves with different
shapes
and tachycardia confirm that the rhythm is multifocal atrial tachycardia (MAT). This arrhythmia may be easily confused
with atrial fibrillation. In MAT, there is only one P wave between two consecutive QRS complexes. On the other hand, there
are more than one P wave between two consecutive QRS complexes in patients with atrial fibrillation.

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ECG 3. The ECG above belongs to another patient with COPD. The rhythm is multifocal atrial tachycardia (MAT).
As seen in this simultaneous 12-lead ECG,
it may not be possible to see P waves with at least 3 different shapes in all leads.


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ECG 4. MAT in another patient with COPD. The presence of P waves with at least 3 different shapes is enough for diagnosis.


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ECG 5. MAT in another patient under CPAP therapy.
The presence of P waves with at least 3 different shapes is enough for diagnosis.


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ECG 6. The ECG above belongs to a 78 years-old woman with chronic obstructive pulmonary disease. She was under
mechanical ventilation. The ECG was recorded 3 hours after cardiac arrest.
P waves with at least 3 different shapes suggest
multifocal atrial tachycardia. In addition,
bidirectional PVC is also seen.


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ECG 7. Ashman phenomenon in a patient with multifocal atrial tachycardia. There are
P waves with more than 3 different shapes .
Aberrantly conducted beats
may be seen consecutively. Aberration follows the long-short cycle.

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