This is manifest on the ECG as the PR interval, which is about less than 200 milliseconds, the time from activation of the atria (manifest as the P wave) and activation of the ventricles (manifest as the QRS complex).Individuals with JET have a "short-circuit" in their heart, where the electricity bypasses the AV node, causing the heart to beat faster than normal. The cause of the arrhythmia, the ectopic focus, is usually near the AV node in the triangle of Koch (a rough triangle with points at the coronary sinus, the tendon of Todaro, and the tricuspid valve).Patients of heart surgery may experience an accelerated narrow complex tachycardia, usually within the first 24–48 hours (but occasionally longer) after surgery. There may be atrio-ventricular disassociation with more ventricular signals than atrial signals. The cause of JET is felt to be due to manipulation of the tissue surrounding the AV node during surgery, however debate exists regarding the exact cause, as it is seen after procedures even without significant manipulation of this area.JET-like symptoms can also manifest congenitally and in the first six months of life. This syndrome, which may also referred to as His bundle tachycardia, is resistant to therapy and can be difficult to treat. Diagnosis
JET is most commonly diagnosed using a 12-lead ECG. The appearance is usually of a tachycardia with rapid, regular ventricular rates of 170-260 beats per minute. The QRS complexes are usually narrow, but may be broad if a bundle branch block is present.
Tachycardia (from the Greek takhys, meaning "swift", and kardia, meaning heart) means a swift heart rate.By this definition, junctional ectopic tachycardia is an abnormally swift heart rhythm due to cells firing within the heart near the AV node. References


== External links ==