What Is Multifocal Atrial Tachycardia?

Reviewed by James Beckerman, MD, FACC on March 16, 2020

Multifocal atrial tachycardia (MAT) is a type of irregular heartbeat in which the heart beats faster than it should. It’s one of many types of heart arrhythmias or irregular heart rhythms.

When your heart beats normally, there are between 60 and 100 beats per minute. Anytime the heart beats faster than 100 beats per minute, it’s called a tachycardia (pronounced tak-ih-KAHR-dee-uh).

This happens because the signals that control your heartbeat aren’t working right. In this type of tachycardia, those irregular signals come from three or more places in the heart’s upper chambers. That’s where MAT gets its name. “Multifocal” means having more than one focus and “atrial” refers to the heart’s two upper chambers, called atria.

Causes

Doctors don’t know exactly what causes MAT. Part of the reason it’s poorly understood is that MAT isn’t a very common type of arrhythmia.

MAT usually happens in older people, with an average age of 70. But it sometimes also happens in children or young adults. It’s more common in men and in people with one or more other health problems. These problems may include:

Sometimes MAT happens in people after major surgery. It also can happen in people who have an imbalance of electrolytes, such as magnesium or potassium. People taking certain medications used to treat heart or lung problems may be more likely to have MAT.

Diagnosis

Sometimes people with MAT have these signs:

But many times, people with MAT don’t feel like their heart isn’t beating normally or notice other signs. Doctors often find it unexpectedly in people with other health problems.

It’s hard to tell from a physical exam if a person has MAT. But this irregular heart rhythm will show up in an electrocardiogram (EKG). This test records electrical signals in the heart. If a doctor finds MAT on an EKG, your pulse also may be fast and irregular. Without an EKG, it’d be hard to tell the difference between MAT and some other type of arrhythmia.

Treatment

MAT itself isn’t usually life-threatening. But if you have it, it’s likely that you have other serious health conditions -- and those can be very serious. In most cases, the best way to treat MAT is to treat the other health problems. Once those are more controlled, the heart irregularity will likely get better.

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Treatments used by doctors to correct other arrhythmias usually don’t work to treat MAT. Sometimes MAT goes away and then comes back.

If you have an electrolyte imbalance, your doctor may start by trying to correct it. (Electrolytes include sodium, potassium, calcium, and magnesium.) Your doctor may recommend other treatments, such as beta-blockers or calcium channel blockers, depending on what other conditions you have. If you have MAT that doesn’t go away, your doctor may consider whether surgery is an option.

People with MAT often need treatment in the hospital or intensive care unit (ICU). Keep in mind that this is because of the other health problems people with MAT tend to have, not the abnormal heart rhythm itself.

WebMD Medical Reference

Sources

SOURCES:

Mayo Clinic: “Supraventricular tachycardia,” “Electrocardiogram (ECG or EKG).”

StatPearls: “Multifocal Atrial Tachycardia (MAT).”

The New England Journal of Medicine: “Multifocal Atrial Tachycardia.”

Medscape: “Multifocal Atrial Tachycardia.”

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