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Paroxysmal supraventricular tachycardia (PSVT)
Alternative namesA rapid heart rate , which occurs from time to time (paroxysmal). PSVT starts by events taking place above the ventricles.
Causes, incidence, and risk factors
Normally, the chambers of the heart (atria and ventricles) contract in a coordinated manner. The contractions are caused by an electrical signal that begins in the sinoatrial node (also called the sinus node or SA node).
The signal is conducted through the atria (the upper heart chambers) and stimulates the atria to contract. The electrical signal then passes through the atrioventricular node (AV node), and travels through the ventricles (the larger, lower chambers), stimulating them to contract.
Risks include excessive smoking, caffeine , and alcohol use . PSVT can occur with digitalis toxicity . It can be a form of a re-entry tachycardia (an electrical current is caught in a reentrant loop, excessively stimulating the heart), as in the case of Wolff-Parkinson-White syndrome .
Note: Symptoms may start and stop suddenly, and can last for a few minutes or several hours. A PSVT that last for more than 50% of the day is considered a permanent or incessant PSVT.
Signs and testsAn examination during a PSVT epsiode detects a regular, rapid heart rate . The heart rate may be 150 to 250 beats per minute (bpm) (in children the heart rate tends to be very high). There may be signs of poor perfusion (i.e., circulation) such as light-headedness. Between episodes of PSVT, the heart rate is normal (60 to 100 bpm).
PSVT can occur with few or no symptoms, and may not require treatment. If symptoms occur or there are underlying cardiac disorders, treatment may be necessary.
Electrical cardioversion ( shock ) is successful in conversion of PSVT to a normal sinus rhythm in many cases. Another way to rapidly convert a PSVT is to administer intravenous medications, including adenosine and verapamil. Other medications may be used, such as esmolol, procainamide, beta-blockers, and propafenone.
Aside from treating isolated episodes of PSVT, some patients may require a long-term or definitive treatment of the PVST which is directed toward the prevention or complete erradication of further episodes or arrhythmia. Such long-term treatment includes:
Expectations (prognosis)PSVT is generally not life-threatening, unless other cardiac disorders are present.
Calling your health care providerCall your health care provider if:
PreventionAvoid excessive smoking, caffeine , and alcohol use . Medications used to treat the disorder may be given as a preventive (prophylactic) treatment in people at a high risk or who have had previous episodes of PSVT.
Update Date: 5/3/2002Elena Sgarbossa, M.D., Department of Cardiology, Rush-Presbyterian St. Luke's Medical Ctr., Chicago, IL. Review provided by VeriMed Healthcare Network.
Last updated: Tue, 06 Jan 2009 00:20:03 GMT