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Paroxysmal atrial tachycardia (PAT) is a condition in which the upper chambers of the heart, the atria, begin to beat irregularly, sometimes producing heartbeats as fast as 200-220 beats per minute (bpm). The condition is called paroxysmal, since it occurs suddenly and without warning. In people with no abnormal heart conditions, this is usually considered not a dangerous arrhythmia, but in people who have had corrective heart surgeries especially the Fontan operation, it can be life threatening.
There are a few potential causes of PAT. Some people have additional heart tissue that acts as an extra conductor, causing the heart to occasionally produce rapid beats. This is called Wolff Parkinson White Syndrome (WPW). In other cases, a small abnormality exists in the atrial node, creating occasional racing of the heart or palpitations. Other times, the condition can be induced by people who are alcoholics, or by those who consume excess caffeine. Women who are menstruating may also experience palpitations.
It’s difficult to diagnose paroxysmal atrial tachycardia since it doesn’t happen all the time. Unless you are doing an EKG on a person while it is happening, you won’t necessarily see anything abnormal in the heart rhythm. If a person is experiencing palpitations, what usually occurs is that they wear what is called a cardiac event monitor. If they begin experiencing rapid heartbeat, they press a button, which records the “event” via several probes attached to the chest. An event monitor can be worn for several weeks in order to capture PAT episodes. Alternately, if the symptoms are occurring frequently, a 24-hour Holter monitor may be used to catch fast and extra beats.
The symptoms of paroxysmal atrial tachycardia can last for a few minutes to several hours. When rapid heartbeat remains for more than a minute or two, a person can feel out of breath, have chest pain, dizziness, have a panic attack, or faint. It is a scary thing to endure several hours of this condition, even when it does not cause pain or fainting. Dizziness and fainting can be caused by the atrial chambers not being able to fill fully, thus leading to inadequate blood supply to the body and lungs. Though this is rarely life threatening, with children who’ve undergone surgeries like the Fontan, it can result in sudden death.
If paroxysmal atrial tachycardia occurs rarely, the condition may not be treated. Doctors may instead suggest avoiding caffeinated beverages and keeping a log of occurrences. When it occurs often, doctors look for cause, and ways to treat it. Where WPW exists, doctors called electrophysiologists will perform a cardiac ablation, a non-surgical procedure done via catheterization that essentially destroys the extra tissue sending false signals to the heart to beat too rapidly. In many cases, people might require medication when PAT is occurring frequently and WPW is not present.
When paroxysmal atrial tachycardia doesn’t respond to medications, cardiac ablation may be tried, or patients can have a defibrillator implanted (similar to a pacemaker), which helps to control and regulate heart rhythms. Patients who have had the Fontan are quite likely to have this method of treatment, since for them, the heart beating at a rapid pace can be life threatening.