What causes supraventricular tachycardia?
Supraventricular tachycardia (SVT) is often caused by having extra electrical circuits in the heart. It may also be caused by valve disease or blockage of the arteries. Thyroid disease or heart failure may also cause this problem. Other causes may be drinking too much alcohol, smoking, or drinking too much caffeine, such as in coffee or soda.. Using too much cold
medicine may also cause SVT. Stress may cause you to have a SVT attack.
The normal heartbeat is synchronised by a collection of muscle fibres in the upper right chamber of the heart called the sinoatrial node. This is the heart's natural pacemaker. In SVT, fast impulses start up elsewhere, above the ventricles and override the natural pacemaker. The term SVT refers to several different kinds of arrhythmias. The most common is Paroxysmal Supraventricular Tachycardia (PSVT). The paroxysm (temporary episode of disturbance of heart rhythm) are most commonly is caused by a short circuit in the electrical system of the heart, which causes the electrical signal to continuously travel around in a circle, forcing the heart to beat rapidly.
Another specific type of SVT includes Wolff-Parkinson-White syndrome, where there is an abnormal electrical connection between the atria and ventricles. This extra tissue forms a short circuit between these chambers, again causing a fast heart beat. In SVT the heart beats so fast that the heart muscle doesn’t relax between contractions, this reduces the amount of blood being pumped around the body. Supraventricular tachycardia may be a side effect of medications such as digitalis, asthma medications, herbal supplements and cold remedies. Caffeine and stress can also cause arrhythmias.
In some cases, the cause of supraventricular tachycardia is unknown.