What is SVT?
SVT (short for Supraventricular Tachycardia) is a heart rhythm problem causing your heart to beat too fast. It’s caused by a faulty short circuit in your heart and often affects young healthy people. SVT is a type of arrhythmia which means an abnormal heartbeat.Tachycardia means a rapid heart rate of more than 100 beats per minute.
What are the symptoms of SVT?
A heart that beats too fast or slow can cause:
- Lightheadedness or dizziness
- Palpitations (skipping, fluttering or pounding in the chest)
- Chest pressure or pain
- Shortness of breath
- Fainting spells
Sometimes however there are no symptoms. If left untreated, some types of SVT can increase the risk of dying suddenly.
What are the causes and triggers of SVT?
Supraventricular Tachycardia is caused by a problem with electrical impulses in the heart. Heartbeats are initiated by the hearts natural pacemaker, the sinus node. The node produces electrical signals that pass through the upper chambers of the heart (atria) causing them to contract and pump blood into the lower heart chambers.Electricity passes from the atria through a specialised node in the middle of the heart (the AV node) and into the ventricles (the bottom chambers) via specialised conduction tissue called the His-Purkinje system.
Episodes of SVT occur when a problem develops in this system. It results in rapid signals being sent around the heart, increasing the speed at which the heart beats.
SVT is usually triggered by extra heartbeats (ectopic beats) which everyone has. It can also be triggered by:
- Some medications including asthma medications, herbal supplements and cold remedies
- Drinking large quantities of caffeine or alcohol
- Tiredness, stress and emotional upset
- Smoking lots of cigarettes
However, in the majority of cases, there is no identifiable trigger for SVT.
What are the treatments for SVT?
There are several treatment options available depending on the type and severity your arrhythmia and your test results.
Certain anti-arrhythmic drugs change electrical propagation in the heart and help prevent irregular or rapid heart rhythms. Medications include beta-blockers, verapamil, flecainide, sotalol, propafenone and sometimes amiodarone.
Ablation involves a procedure where fine wires are advanced from veins at the top of the leg to the heart. Heat applied from the tip of one of the wires causes a tiny area of localised tissue damage which destroys the limb of the abnormal circuit and so cures the arrhythmia.