Multifocal atrial tachycardia

From Wikipedia, the free encyclopedia
Jump to: navigation, search
For other uses, see MAT (disambiguation).
Multifocal atrial tachycardia
Classification and external resources
Multifocal atrial tachycardia - MAT.png
Multifocal atrial tachycardia
ICD-9 427.89
DiseasesDB 31111
MedlinePlus 000186
eMedicine article/759135

Multifocal atrial tachycardia (MAT) is a cardiac arrhythmia,[1] specifically a type of supraventricular tachycardia, that is associated with chronic obstructive pulmonary disease (COPD). Normally, the heart rate is controlled by a cluster of cells called the sinoatrial node (SA node). When a number of different clusters of cells outside of the SA node take over control of the heart rate, and the rate exceeds 100 beats per minute, that is called multifocal atrial tachycardia.

"Multifocal atrial rhythm" is the condition in the absence of tachycardia.[2]

Causes and epidemiology[edit]

It is more common in the elderly.[3]

It is mostly common in patients with lung disorders, but it can occur after acute MI, hypokalemia, and hypomagnesemia.

It is sometimes associated with digitalis toxicity in patients with heart disease.

It is most commonly associated with hypoxia and COPD. Additionally, it can be caused by theophylline toxicity, a drug with a narrow therapeutic index commonly used to treat COPD. Theophylline can cause a number of different arrhythmias when in excess, and thus further predisposes COPD patients to MAT. Toxicity often occurs following illness or co-administration of drugs which inhibit the cytochrome P450 system and thus lower its clearance from the body.

Presentation and pathophysiology[edit]

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. Narrow QRS complexes are visible as well.

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.

Treatment[edit]

Its rate may in some cases be reduced by administering verapamil.

Administration of oxygen may play a role in the treatment of some patients.[4]

References[edit]

  1. ^ Bradley DJ, Fischbach PS, Law IH, Serwer GA, Dick M (August 2001). "The clinical course of multifocal atrial tachycardia in infants and children". J. Am. Coll. Cardiol. 38 (2): 401–8. doi:10.1016/S0735-1097(01)01390-0. PMID 11499730. 
  2. ^ "ECG Learning Center - An introduction to clinical electrocardiography". Library.med.utah.edu. Retrieved 2013-04-24. 
  3. ^ McCord J, Borzak S (January 1998). "Multifocal atrial tachycardia". Chest 113 (1): 203–9. doi:10.1378/chest.113.1.203. PMID 9440591. 
  4. ^ American College of Physicians; Acp (15 June 2008). MKSAP for students four. ACP Press. pp. 37–. ISBN 978-1-934465-03-5. Retrieved 11 November 2010.