The heart has an inbuilt electrical system that tells it when to pump and when to relax. This keeps the heart in order and ensures good effective contractions (pumping) rather than something disorganised. In some people there is a tiny invisible short circuit. This short circuit triggers a beat of the heart when it shouldn't have done. The result is a chain reaction of multiple beats at very fast heart rates. Older children may describes rapid palpitations (heart racing) and all children will often look pale, may begin crying or even collapse. This extremely fast heart rate may start and stop very quickly with no reason at all. It may last only a few minutes or it may take treatment in hospital to stop. This rapid beat caused by a short circuit is called Supra-ventricular Tachycardia - the posh way of saying a fast heart rate (tachycardia) coming from a short circuit above (supra) the main pumping chambers (ventricles).
Click here to see the British Heart Foundation leaflet on Supraventricular Tachycardia (SVT)or click here to go to the British Heart Foundation website.
Click here to see the Children's Heart Federation leaflet on Supraventricular Tachycardia (SVT)or click here to go to the Children's Heart Federation website.