Junctional tachycardia: Difference between revisions
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{{SK}} accelerated junctional rhythm | {{SK}} accelerated junctional rhythm | ||
==Overview== | ==Overview== | ||
'''Junctional tachycardia''' is a form of [[supraventricular tachycardia]] characterized by electrical impulse generation from the [[AV node]]. | '''Junctional tachycardia''' is a form of [[supraventricular tachycardia]] characterized by electrical impulse generation from the [[AV node]] that is independent of or dissociated from that of the [[sinoatrial node]] ([[SA node]]). | ||
==Pathophysiology== | ==Pathophysiology== |
Revision as of 15:49, 4 September 2012
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
Synonyms and keywords: accelerated junctional rhythm
Overview
Junctional tachycardia is a form of supraventricular tachycardia characterized by electrical impulse generation from the AV node that is independent of or dissociated from that of the sinoatrial node (SA node).
Pathophysiology
Normally, the atrioventricular node (AVN) can generate an escape rhythm of 40-60 beats per minute in case the sinoatrial node (SA node) or atrial pacemakers fail (sinus arrest) or slow (sinus bradycardia) or if there is complete heart block. This junctional escape rhythm generates a normal, narrow QRS complex rhythm at a rte below 60 beats per minute (junctional bradycardia) as the electrical impulses once they are generated are conducted with normal velocity down the usual pathways. Retrograde P waves (i.e. upside down) P waves due to retrograde or backward conduction may or may not be present.
In contrast to a junctional escape rhythm or junctional bradycardia at a rate of 40-60 beats per minute, junctional tachycardia is faster, at a rate > 60 beats per minute. Junctional tachycardia generates a normal, narrow QRS complex rhythm as the electrical impulses are conducted with normal velocity down the usual pathways. Retrograde P waves (i.e. upside down) P waves due to retrograde or backward conduction may or may not be present.
The cause of the more rapid firing of the atrioventricular node is thought to be due to enhanced automaticity as a result of abnormal Ca metabolism in the sarcoplastic reticulum.[1]
Causes
Differentiation of Junctional Tachycardia from other Tachycardias
- Sinus tachycardia:
- Atrioventricular nodal reentrant tachycardia: It can appear similar to atrioventricular nodal reentrant tachycardia.[3]
One form is junctional ectopic tachycardia.
See also
References
- ↑ Kim D, Shinohara T, Joung B, Maruyama M, Choi EK, On YK. Calcium dynamics and the mechanisms of atrioventricular junctional rhythm. J Am Coll Cardiol. Aug 31 2010;56(10):805-12.
- ↑ "Junctional Rhythm: Overview - eMedicine". Retrieved 2008-12-21.
- ↑ Srivathsan K, Gami AS, Barrett R, Monahan K, Packer DL, Asirvatham SJ (2008). "Differentiating atrioventricular nodal reentrant tachycardia from junctional tachycardia: novel application of the delta H-A interval". J. Cardiovasc. Electrophysiol. 19 (1): 1–6. doi:10.1111/j.1540-8167.2007.00961.x. PMID 17916156. Unknown parameter
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