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

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

• Chest tightness
• Light-headedness
• Fainting
• Sensation of feeling the heart beat (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

An examination shows a fast irregular heartbeat, usually of 100 to 130 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 -- allow you to start recording if symptoms occur
• If you are in the hospital, your heart rhythm will be monitored 24 hours a day

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 medications, such as theophylline, which can increase the heart rate
• Taking medicines to slow the heart rate (if the heart rate is too fast), such as such as calcium channel blockers (verapamil, diltiazem) or beta-blockers

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

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

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

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

Olgin JE, Zipes DP. Specific arrhythmias: diagnosis and treatment. In: Bonow RO, Mann DL, Zipes DP, Libby P, eds. Braunwald's Heart Disease: A Textbook of Cardiovascular Medicine. 9th ed. St. Louis, Mo: WB Saunders; 2011:chap 39.

Zimetbaum P. Cardiac arrhythmia with supraventricular origin. In: Goldman L, Schafer AI, eds. Cecil Medicine. 24th ed. Philadelphia, Pa: Saunders Elsevier; 2011:chap 64.