Junctional ectopic tachycardia is a form of junctional tachycardia due to irregular conduction from or through the atrioventricular node.
It is usually either present at birth, or emerges after surgery.
Junctional ectopic tachycardia (JET) can be better understood by breaking down the meaning of each word. Junctional: atrioventricular node (the junction between the atria and the ventricles); Ectopic: an abnormal location; and Tachycardia: a fast heart rate.
In other words, Junctional ectopic tachycardia (JET) is an abnormal heart rhythm due to increased automaticity of the cells within the heart near the AV node (the “junction” between the atria and the ventricles). This type of arrhythmia may be congenital, acquired or after heart surgery.
Post operative JET
This presents with 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 then 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.
Treatment is aimed at slowing the rate by correcting acidosis, correcting electrolytes (especially magnesium and calcium), cooling the patient, and antiarrhythmic medications. Occasionally pacing of the atrium at a rate higher than the JET may allow improved cardiac function by allowing atrial and ventricular synchrony.
Non-post operative JET
Junctional ectopic tachycardia unrelated to the postoperative period is a rare arrhythmia. The cause of the arrhythmia, the ectopic focus, is usually near the AV node in the triangle of Koch (between the CS, the AV node and the tricuspid valve).
The congenital form, occurring in the first 6 months of life, is rare, and can be difficult to treat. It is unfortunately associated with a high mortality and mobidity. JET occurring after the first six months of life is somewhat more variable, but may still be difficult to control.
Treatment of non post-operative JET is typically with antiarrhythmic medications or a cardiac catheterization with ablation. A cardiac catheterization may be performed to isolate and ablate (burn or freeze) the source of the arrhythmia. This can be curative in the majority of cases. The use of radiofrequency energy is infrequently associated with damage to the normal conduction due to the close proximity to the AV node, the normal conduction tissue. The use of cryotherapy (cold energy) appears to be somewhat safer, and can also be effective for the treatment of JET.
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Source: Wikipedia