Junctional tachycardia is a form of supraventricular tachycardia

Supraventricular tachycardia

Supraventricular tachycardia is a general term that refers to any rapid heart rhythm originating above the ventricular tissue. Supraventricular tachycardias can be contrasted to the potentially more dangerous ventricular tachycardias - rapid rhythms that originate within the ventricular...

 characterized by involvement of the AV node. It can be contrasted to atrial tachycardia

Atrial tachycardia

Atrial tachycardia is a type of atrial arrhythmia in which the heart's electrical impulse comes from an ectopic atrial pacemaker rather than from the SA node. Atrial tachycardias are characterized by very regular rates ranging from 140–220 bpm....

. It is a tachycardia associated with the generation of impulses in a locus in the region of the atrioventricular node.

It can be associated with digitalis

Digitalis

Digitalis is a genus of about 20 species of herbaceous perennials, shrubs, and biennials that are commonly called foxgloves. This genus was traditionally placed in the figwort family Scrophulariaceae, but recent reviews of phylogenetic research have placed it in the much enlarged family...

 toxicity. It may be due to coronary artery disease and conduction system disease.

It can appear similar to atrioventricular nodal reentrant tachycardia.

One form is junctional ectopic tachycardia

Junctional ectopic tachycardia

Junctional ectopic tachycardia is a rare syndrome of the heart that manifests in patients recovering from heart surgery. It is characterized by cardiac arrhythmia, or irregular beating of the heart, caused by abnormal conduction from or through the atrioventricular node...

.