junctional tachycardia
{{Short description|Abnormally fast heartbeat, the cause of which involves the atrioventricular node}}
{{Infobox medical condition (new)
| name = Junctional tachycardia
| synonyms =
| image = Junctional Tachycardia.jpg
| alt =
| caption = ECG showing junctional tachycardia. Narrow complex QRS. No P waves. Heart rate fast.
| pronounce =
| field =
| symptoms =
| complications =
| onset =
| duration =
| types =
| causes =
| risks =
| diagnosis =
| differential =
| prevention =
| treatment = Amiodarone to control the rhythm, electrical cardioversion is not used.
| medication =
| prognosis =
| frequency =
| deaths =
}}
Junctional tachycardia is a form of supraventricular tachycardia characterized by involvement of the AV node.{{DorlandsDict|nine/000957463|junctional tachycardia}} 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.{{Cite journal| last = ROSEN| first = KENNETH| year = 1973| title = Junctional Tachycardia: Mechanisms, Diagnosis, Differential Diagnosis, and Management| url = http://circ.ahajournals.org/content/47/3/654.full.pdf| journal = Circulation| volume = 47| issue = 3| pages = 654–664| doi = 10.1161/01.CIR.47.3.654| pmid = 4571060| access-date = March 1, 2015| doi-access = free}} 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.
File:Double tachycardia with captures.png (rate about 107/min) producing one form of double tachycardia; pairs of ventricular capture (C) beats (5th, 6th, 19th, and 20th beats); see laddergram.]]
Cause
It can be associated with digitalis toxicity.{{cite web |url=http://emedicine.medscape.com/article/155146-overview |title=Junctional Rhythm: Overview - eMedicine |access-date=2008-12-21}} It may also be due to onset of acute coronary syndrome, heart failure, conduction system diseases with enhanced automaticity, or administration of theophylline.{{cite book | last = Aehlert | first = Barbara | title = ECGs Made Easy | publisher = Elsevier | edition = 5th | date = 2013 | page = 160 | isbn = 9780323170574 }}
Diagnosis
On an EKG, junctional tachycardia exhibits the following classic criteria:
- 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. {{cn|date=February 2021}}
Forms of junctional tachycardia include junctional ectopic tachycardia (JET) and atrioventricular nodal re-entrant tachycardia (AVNRT) which can be distinguished by performing electrophysiological studies.{{cite journal |vauthors=Srivathsan K, Gami AS, Barrett R, Monahan K, Packer DL, Asirvatham SJ |title=Differentiating atrioventricular nodal reentrant tachycardia from junctional tachycardia: novel application of the delta H-A interval |journal=J. Cardiovasc. Electrophysiol. |volume=19 |issue=1 |pages=071004055652013–– |date=January 2008 |pmid=17916156 |doi=10.1111/j.1540-8167.2007.00961.x |s2cid=25084446 }}
Treatment
Amiodarone is used to control the rhythm. Electrical cardioversion is not used.{{cn|date=February 2021}}
See also
References
{{reflist}}
External links
{{Medical resources
| DiseasesDB =
| ICD10 = {{ICD10|I47.1}}
| ICD9 = {{ICD9|xxx}}
| ICDO =
| OMIM =
| MedlinePlus =
| MeSH =
| GeneReviewsNBK =
| GeneReviewsName =
}}
{{Heart diseases}}