Junctional tachycardia is a form of supraventricular tachycardia characterized by involvement of the AV node. It can be contrasted to atrial tachycardia. It is a tachycardia associated with the generation of impulses in a focus in the region of the atrioventricular node.
It can be associated with digitalis toxicity. It may be also be due to onset of acute coronary syndrome, heart failure, conduction system diseases with enhanced automaticity, or administration of theophylline. 
It can appear similar to atrioventricular nodal reentrant tachycardia.
One form is junctional ectopic tachycardia.