Multifocal atrial tachycardia is a
cardiac arrhythmia, specifically a type of
supraventricular tachycardia. It is characterized by an
electrocardiogram (ECG) strip with 3 or more P-waves of variable morphology and varying P-R intervals, plus tachycardia, which is a heart rate exceeding 100 beats per minute.
The P-waves and P-R intervals are variable due to a phenomenon called wandering atrial pacemaker (WAP). The electrical impulse is generated at a different focus within the atria of the heart each time. WAP is positive once the heart generates at least three different P-wave formations from the same ECG lead. Then, if the heart rate exceeds 100 beats per minute, the phenomenon is called multifocal atrial tachycardia.
It is mostly common in patients with lung disorders, but it can be occur after acute MI, hypokalemia, and hypomagnesemia.
It is sometimes associated with digitalis toxicity in patients with heart disease.
Its rate can be reduced by administering verapamil.
References
Dubin, Dale. Rapid Interpretation of EKG's. Edition V. Cover Publishing Company, Tampa FL.
Cecil Textbook of Medicine
