Paroxysmal Supraventricular Tachycardia
- supraventricular tachycardia
- paroxysmal atrial tachycardia
Paroxysmal supraventricular tachycardia, or PSVT, is an abnormal, fast heartbeat that occurs suddenly. It is triggered in the atria, or upper chambers, of the heart.
What is going on in the body?
The heart has a built-in electrical system. Special pacemaker cells in the heart generate electrical impulses. These cells send electrical current down pathways in the heart muscle. When this occurs at the proper time, a normal heart rhythm is produced. When the electrical current starts in the wrong place or goes in the wrong direction at the wrong time, an abnormal heart rhythm, or arrhythmia, results. PSVT occurs when electrical current flows in a circle instead of a line. The result is a rapid heart rate, generally 160 to 180 beats per minute.
What are the causes and risks of the condition?
A faulty electrical pathway in the heart causes PSVT. It may be triggered by physical or psychological stress. The risks from PSVT are minimal for otherwise healthy people. Most people require very little, if any, medical intervention. PSVT may cause symptoms in older people with weak hearts or coronary artery disease. In some people, PSVT can cause congestive heart failure or a heart attack. Some people have regular episodes of PVST due to an abnormal development of the electrical pathways present at birth. An example of this is a condition called Wolff-Parkinson-White syndrome.
What can be done to prevent the condition?
Someone who experiences PSVT can be taught simple methods to help stop it. These techniques can be as simple as holding one's breath, gagging oneself with the fingers, or straining very hard. Some cardiologists recommend their patients with PSVT gently massage one of the carotid arteries, while others feel this may potentially be risky.
Some people may take medications only when an episode of PSVT occurs, while others may take medication daily to prevent episodes.
PSVT can be prevented by a procedure called radiofrequency catheter ablation. In this procedure, a specially trained heart specialist or cardiologist places a small tube or catheter in the heart to find the circular electrical pathway. Radio waves are used to eliminate the abnormal electrical pathway. This usually prevents any more episodes of PSVT from occurring.
How is the condition diagnosed?
PSVT is diagnosed with an electrocardiogram, or ECG. The pattern is simple to recognize -- so long as the abnormal rhythm occurs while the ECG is hooked up. Occasionally the patient may carry an "event monitor" for several weeks. This device is programmed to detect an episode of abnormal rhythm and generate an ECG tracing of it at the exact moment, and record it for a physician to review.
Long Term Effects
What are the long-term effects of the condition?
PSVT is usually more of a bother than an illness. Many people who experience PSVT can stop the abnormal rhythm with the techniques taught by their healthcare provider. The abnormal heart rhythm may correct itself. Other people may need to go to the emergency department to get medication for episodes of PSVT.
What are the risks to others?
There are no risks to others.
What are the treatments for the condition?
Someone who experiences PSVT for the first time usually goes to the emergency department. Simple techniques often stop the PSVT. When these methods do not work, a medication called adenosine may be tried. This medication is given by vein. Usually within a few seconds, the medication disrupts the abnormal electrical pathway, resulting in the return of a normal heart rhythm.
What are the side effects of the treatments?
If medication is needed, side effects may be experienced. Complications from radiofrequency catheter ablation are rare, but may include blood clots, new arrhythmias, collapsed lung pericardial tamponade, or even a heart attack. Occasionally, a person may need a permanent pacemaker after this procedure.
What happens after treatment for the condition?
Once PSVT stops and the heart returns to a normal rate and rhythm, there are no lasting effects. If a person has frequent or disabling PSVT, the healthcare provider may recommend radiofrequency catheter ablation.
How is the condition monitored?
Generally, monitoring is not done for PSVT. A person who experiences PSVT should notify the healthcare provider if the frequency or severity of the episodes changes.
Harrison's Principles' of Internal Medicine. Rosen's Emergency Medicine: Concepts and clinical practice.