Paroxysmal atrial tachycardia is a type of arrhythmia (irregular heartbeat). Paroxysmal means that the episode of arrhythmia begins and ends abruptly. Atrial means that arrhythmia originates in the atria or upper chambers of your heart. Tachycardia means that the heart is beating abnormally fast. Paroxysmal atrial tachycardia (PAT) is also known as paroxysmal supraventricular (meaning above the ventricles) tachycardia (PSVT).
Other types of tachycardia that originate in the atria include atrial fibrillation, atrial flutter, and Wolff-Parkinson-White syndrome.
PAT can cause an adult’s heart rate to increase from 60 to 100 beat beats per minute to 130 to 230 beats per minute. Infants and children normally have higher heart rates than adults—100 to 130 beats per minute. When an infant or child has PAT, his or her heart rate will be greater than 220 beats per minute (Bradley, et al., 2001). PAT is the most common form of tachycardia in infants and children.
In most cases this condition is not life threatening. However, it is uncomfortable and can be alarming. In rare instances, some people with Wolff-Parkinson-White syndrome may develop an extremely rapid heart rate that is life threatening.
PAT occurs when electrical signals starting in the heart’s upper chambers (atria) fire irregularly. This in turn adversely affects the electrical signals transmitted from the sinoatrial node—your heart’s natural pacemaker. This speeds up your heart rate and prevents your heart from having enough time to fill with blood before pumping blood out to the rest of the body. This means that not enough blood or oxygen is transported through the body.
Some people do not experience signs or symptoms of PAT, while others may notice:
- palpitations (increased heart rate)
- angina (pains in the chest)
In rare cases, PAT may cause:
- cardiac arrest
Women are at a higher risk for PAT than men.
Your emotional health can affect your risk for PAT. If you are physically exhausted or have anxiety, then you are at high risk for the condition. In addition, if you drink excessive amounts of caffeine or drink alcohol daily, your risk for PAT goes up.
Having other heart issues such as a history of heart attack or mitral valve disease may increase your risk. Children suffering from congenital heart disease are at a high risk of PAT.
Your doctor may recommend an electrocardiogram (ECG) test to help diagnose PAT. An ECG test is designed to measure the electrical activity in your heart. Your doctor will ask you to lie down and will then attach a number of electrodes to your chest, arms, and legs.
He or she will ask you to remain still and also to hold your breath for just a few seconds. It is important to try to stay still and relaxed, as even a slight movement can affect the results.
The electrodes are attached to wires that transmit your heart’s electrical activity to a machine that prints them out as a series of wavy lines. Your doctor will be able to examine this data to determine if you have a heart rate that is higher than normal.
The test may also be conducted during a period of light exercise or activity to measure the changes in your heart under stress.
Your doctor may also want to test your blood pressure.
Most people with PAT won’t ever require treatment for their condition. However, your doctor may recommend treatment if your episodes occur frequently or last for a considerable length of time.
Your doctor may suggest one of the following vagal maneuvers be used during an episode of PAT. Vagal maneuvers stimulate your vagus nerve in order to slow your heart rate.
- a carotid sinus massage—your doctor will apply a gentle pressure to your neck at the location where your carotid artery branches.
- applying gentle pressure to the closed eyelids
- the valsalva maneuver—pressing your nostrils together while exhaling through your nose
- the dive reflex—suddenly immersing your face or body in cool water
If you frequently experience episodes of PAT, and the maneuvers outlined above don’t restore your normal heart rate, your doctor may prescribe medication. If you are in a medical setting like a doctor’s office or hospital when you’re experiencing PAT, you may be given an injection of flecainide (Tambocor) or propafenone (Rythmol) to slow your heart rate. Your doctor may also prescribe one of those medications in pill form that you can take during a future episode of PAT.
Your doctor may recommend that you reduce your intake of caffeine and alcohol, and stop or reduce your use of tobacco. He or she will also want to help ensure that you are getting plenty of rest.
In rare and extreme cases, your doctor may suggest catheter ablation. This is a nonsurgical procedure that involves the removal of the area of the heart that is causing the increased heart rate. During the procedure, your doctor will place a catheter against the trigger area and transmit radio-frequency energy through it so that it will produce enough heat to destroy the precise area.
PAT is not a life-threatening condition. The periods of sudden rapid heartbeat are much more uncomfortable than they are dangerous. The outlook for someone who has PAT is generally positive.
Complications of PAT vary with the rate and duration of the tachycardia and whether the individual has an underlying heart condition. Some people with PAT may be at risk for blood clots that could result in a heart attack or a stroke. In those cases, doctors usually prescribe medications like dabigatran (Pradaxa) or warfarin (Coumadin), which thin the blood and reduce the risk for blood clots.
In rare cases, complications may include congestive heart failure and cardiomyopathy.
The best way to prevent PAT is to avoid smoking and limit drinking alcohol and caffeinated beverages. Getting regular exercise and plenty of rest is also advised. By maintaining a healthy diet and lifestyle and keeping your weight in a healthy range, you can also significantly reduce your risk of PAT.