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Multifocal atrial tachycardia

Chaotic atrial tachycardia

 

Multifocal atrial tachycardia (MAT) is a rapid heart rate. It occurs when too many signals (electrical impulses) are sent from the upper heart (atria) to the lower heart (ventricles).

Causes

 

The human heart gives off electrical impulses, or signals, which tell it to beat. Normally, these signals begin in an area of the upper right chamber called the sinoatrial node (sinus node or SA node). This node is considered the heart's "natural pacemaker." It helps control the heartbeat. When the heart detects a signal, it contracts (or beats).

The normal heart rate in adults is about 60 to 100 beats per minute. The normal heart rate is faster in children.

In MAT, many locations in the atria fire signals at the same time. Too many signals lead to a rapid heart rate. It most often ranges between 100 to 130 beats per minute or more in adults. The rapid heart rate causes the heart to work too hard and not move blood efficiently. If the heartbeat is very fast, there is less time for the heart chamber to fill with blood between beats. Therefore, not enough blood is pumped to the brain and the rest of the body with each contraction.

MAT is most common in people age 50 and over. It is often seen in people with conditions that lower the amount of oxygen in the blood. These conditions include:

  • Bacterial pneumonia
  • Chronic obstructive pulmonary disease (COPD)
  • Congestive heart failure
  • Lung cancer
  • Lung failure
  • Pulmonary embolism

You may be at higher risk for MAT if you have:

  • Coronary heart disease
  • Diabetes
  • Had surgery within the last 6 weeks
  • Overdosed on the drug theophylline
  • Sepsis

When the heart rate is less than 100 beats per minute, the arrhythmia is called "wandering atrial pacemaker."

 

Symptoms

 

Some people may have no symptoms. When symptoms occur, they can include:

  • Chest tightness
  • Lightheadedness
  • Fainting
  • Sensation of feeling the heart is beating irregularly or too fast (palpitations)
  • Shortness of breath
  • Weight loss and failure to thrive in infants

Other symptoms that can occur with this disease:

  • Breathing difficulty when lying down
  • Dizziness

 

Exams and Tests

 

A physical exam shows a fast irregular heartbeat of over 100 beats per minute. Blood pressure is normal or low. There may be signs of poor circulation.

Tests to diagnose MAT include:

  • ECG
  • Electrophysiologic study (EPS)

Heart monitors are used to record the rapid heartbeat. These include:

  • 24-hour Holter monitor
  • Portable, long-term loop recorders that allow you to start recording if symptoms occur

If you are in the hospital, your heart rhythm will be monitored 24 hours a day, at least at first.

 

Treatment

 

If you have a condition that can lead to MAT, that condition should be treated first.

Treatment for MAT includes:

  • Improving blood oxygen levels
  • Giving magnesium or potassium through a vein
  • Stopping medicines, such as theophylline, which can increase heart rate
  • Taking medicines to slow the heart rate (if the heart rate is too fast), such as calcium channel blockers (verapamil, diltiazem) or beta-blockers

 

Outlook (Prognosis)

 

MAT can be controlled if the condition that causes the rapid heartbeat is treated and controlled.

 

Possible Complications

 

Complications may include:

  • Cardiomyopathy
  • Congestive heart failure
  • Reduced pumping action of the heart

 

When to Contact a Medical Professional

 

Call your health care provider if:

  • You have a rapid or irregular heartbeat with other MAT symptoms
  • You have MAT and your symptoms get worse, do not improve with treatment, or you develop new symptoms

 

Prevention

 

To reduce the risk of developing MAT, treat the disorders that cause it right away.

 

 

References

Olgin JE, Zipes DP. Specific arrhythmias: diagnosis and treatment. In: Bonow RO, Mann DL, Zipes DP, Libby P, Braunwald E, eds. Braunwald's Heart Disease: A Textbook of Cardiovascular Medicine. 10th ed. Philadelphia, PA: Elsevier Saunders; 2015:chap 37.

Zimetbaum P. Cardiac arrhythmia with supraventricular origin. In: Goldman L, Schafer AI, eds. Goldman's Cecil Medicine. 25th ed. Philadelphia, PA: Elsevier Saunders; 2016:chap 64.

 
  • Heart, section through the middle

    Heart, section through the middle - illustration

    The interior of the heart is composed of valves, chambers, and associated vessels.

    Heart, section through the middle

    illustration

  • Heart, front view

    Heart, front view - illustration

    The external structures of the heart include the ventricles, atria, arteries and veins. Arteries carry blood away from the heart while veins carry blood into the heart. The vessels colored blue indicate the transport of blood with relatively low content of oxygen and high content of carbon dioxide. The vessels colored red indicate the transport of blood with relatively high content of oxygen and low content of carbon dioxide.

    Heart, front view

    illustration

  • Conduction system of the heart

    Conduction system of the heart - illustration

    The intrinsic conduction system sets the basic rhythm of the beating heart by generating impulses which stimulate the heart to contract.

    Conduction system of the heart

    illustration

    • Heart, section through the middle

      Heart, section through the middle - illustration

      The interior of the heart is composed of valves, chambers, and associated vessels.

      Heart, section through the middle

      illustration

    • Heart, front view

      Heart, front view - illustration

      The external structures of the heart include the ventricles, atria, arteries and veins. Arteries carry blood away from the heart while veins carry blood into the heart. The vessels colored blue indicate the transport of blood with relatively low content of oxygen and high content of carbon dioxide. The vessels colored red indicate the transport of blood with relatively high content of oxygen and low content of carbon dioxide.

      Heart, front view

      illustration

    • Conduction system of the heart

      Conduction system of the heart - illustration

      The intrinsic conduction system sets the basic rhythm of the beating heart by generating impulses which stimulate the heart to contract.

      Conduction system of the heart

      illustration

    A Closer Look

     

      Tests for Multifocal atrial tachycardia

       

       

      Review Date: 5/5/2016

      Reviewed By: Michael A. Chen, MD, PhD, Associate Professor of Medicine, Division of Cardiology, Harborview Medical Center, University of Washington Medical School, Seattle, WA. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.

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