Junctional tachycardia

Junctional tachycardia is a form of supraventricular tachycardia characterized by involvement of the AV node.^[1] 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 due to an A-V disassociation.^[2] In general, the AV junction's intrinsic rate is 40-60 bpm so an accelerated junctional rhythm is from 60-100bpm and then becomes junctional tachycardia at a rate of >100 bpm.

Junctional tachycardia (rate about 115/min) dissociated from a slightly slower sinus tachycardia (rate about 107/min) producing one form of double tachycardia; pairs of ventricular capture (C) beats (5th, 6th, 19th, and 20th beats); see laddergram.

Junctional tachycardia
ECG showing junctional tachycardia. Narrow complex QRS. No P waves. Heart rate fast.
Treatment	Amiodarone to control the rhythm, electrical cardioversion is not used.

Cause

It can be associated with digitalis toxicity.^[3] It may also be due to onset of acute coronary syndrome, heart failure, conduction system diseases with enhanced automaticity, or administration of theophylline.^[4]

Diagnosis

On an EKG, junctional tachycardia exhibits the following classic criteria:^[2]

• P-Waves: The p-wave may be inverted in leads II, III and aVF or may not be visible
• Narrow QRS complexes (which is consistent with arrhythmias that conduct through the ventricles using the His-Purkinje system and often originate from the atria or AV junction.)

It can coexist with other superventricular tachycardias due to the disassociation between the SA node and the AV node. ^{[citation needed]}

Forms of junctional tachycardia include junctional ectopic tachycardia (JET) and atrioventricular nodal re-entrant tachycardia (AVNRT) which can be distinguished by performing electrophysiological studies.^[5]

Treatment

Amiodarone is used to control the rhythm. Electrical cardioversion is not used.^{[citation needed]}

See also

• Junctional rhythm