Paroxysmal Supraventricular Tachycardia
Paroxysmal supraventricular tachycardia is a regular, fast (160 to 200 beats per minute) heart rate that originates in heart tissue other than the ventricles (the lower chambers of the heart).
The rapid heart rate of paroxysmal supraventricular tachycardia usually starts and ends suddenly. It can last from a few minutes to several hours. It is felt as an uncomfortable palpitation.
Other symptoms include:
- Chest pain
- Shortness of breath
Usually, the heart is otherwise normal.
Causes and Risk Factors
Paroxysmal supraventricular tachycardia may be set off by a premature heartbeat that rapidly signals the heart to be beat. This may be caused by several abnormalities such as having:
- Abnormal rapid or circling impulses generated in the atria. This is called true paroxysmal atrial tachycardia. This is much less common that the following two abnormalities.
- An abnormal electrical pathway between the upper chambers of the heart the lower ones
- Two electrical pathways in the atrioventricular node
Paroxysmal supraventricular tachycardia is most common among young people and is more unpleasant than dangerous. It may occur during vigorous exercise.
Your doctor will take note of your symptoms, your medical history, your family medical history and do a physical examination. He or she may order an electrocardiogram to identify any abnormal electrical activity in your heart. Because the rapid heart rate comes and goes, it may be necessary to have your heart continuously monitored for 24-hours with a portable Holter monitor while you go about your regular activities.
Several things can be done that stimulate the vagus nerve and decrease the heart rate. These are usually done by or under a doctor's, but people who frequently have this problem can learn to do it themselves. These include:
- Plunging the face into a bowl of ice-cold water
- Rubbing the neck just below the angle of the jaw to stimulate an area on the carotid artery
- Straining as if having a difficult bowel movement
These are most effective when done soon after the arrhythmia starts.
Medical intervention to control the arrhythmia is needed if:
- The above are not effective
- The episode lasts more than 20 minutes
- There are severe symptoms
A doctor can usually stop an episode by giving an injection of a drug. In rare cases where this isn't effective, electroshock may be given to the heart to help return the rhythms to normal.
Drugs such as beta-blockers, digoxin or ones to prevent arrhythmias may be used to help prevent future episodes. More and more often, radiofrequency ablation is done to destroy the tissues where paroxysmal supraventricular tachycardia starts.