Paroxysmal supraventricular tachycardia (PSVT) is a rapid heart rate that occurs periodically. Paroxysmal means that it happens intermittently, or from time to time. A normal resting heartbeat is between 60 and 100 beats a minute. In PSVT, the heart can beat between 160 and 250 beats a minute, and this fast heartbeat is likely to start and stop suddenly. This can go on for minutes and sometimes hours. The three main types of PSVT include atrioventricular nodal reentrant tachycardia (AVNRT), Wolff-Parkinson-White syndrome, and atrial tachycardia.
Atrioventricular nodal reentrant tachycardia (AVNRT) occurs when the heart's electrical impulses move in a circle and reenter areas they have already passed through.
Atrioventricular nodal reentrant tachycardia FAQs
1. What are the symptoms of AVNRT?
While ANVRT may not always cause symptoms, some symptoms that do occur include palpitations, nervousness, anxiety, lightheadedness, neck and chest discomfort, shortness of breath, fainting.
2. What causes AVNRT?
AVNRT is most often caused by the presence of extra pathways in the AV node, although the cause of this is unknown. Women are more likely to develop the condition than men. The extra pathway is present since birth, but most often causes an arrhythmia after the heart has reached its full size when the patient is in their 20s or 30s.
To help diagnose AVNRT, electrophysiologists use one or more of the following tests:
- Electrocardiogram. This device tracks and graphs heart rhythm using electrical signals from the heart.
- Holter monitor. This device monitors and records the heart rhythm continuously for 24-48 hours.
- Event recorder. An event recorder is activated during episodes of fibrillation and records the heart rhythm at that time.
3. How is AVNRT treated?
Treatment of AVNRT depends on the symptoms, how often arrhythmia is experienced, and whether or not another problem is causing the arrhythmia. Common treatments include:
Anti-arrhythmic therapy. This class of prescription medications works to suppress the underlying cause of an arrhythmia. Common antiarrhythmic medications include:
- Beta-blockers. Beta-blockers block receptor cells that respond to epinephrine, a molecule produced by the adrenal gland that stimulates the heartbeat. They slow and regulate the heart rate, reduce the force of heart contractions, and also lower blood pressure and relieve chest pain.
- Calcium channel blockers. Calcium channel blockers prevent calcium from entering the cells that transmit electrical signals. They can be effective in preventing AVNRT episodes.
Radiofrequency catheter ablation. Radiofrequency catheter ablation is the destruction of heart tissue using radiofrequency energy. During ablation, a catheter (a thin, flexible tube) with an electrode tip is positioned on the area of heart tissue that is involved in the arrhythmia. The catheter delivers a burst of energy to destroy tissue that is interfering with the normal transmission of impulses through the heart's electrical system. This same day procedure is over 99% successful in curing AVRNT.