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'''See also:''' [[Junctional bradycardia]] for slow junctional rhythms, and [[junctional tachycardia]] for fast jucntional rhythms
'''See also:''' [[Junctional bradycardia]] for slow junctional rhythms, and [[junctional tachycardia]] for fast jucntional rhythms


==Overview==
==Overview==
'''Junctional rhythm''' describes an abnormal [[heart rhythm]] resulting from impulses coming from a locus of tissue in the area of the [[atrioventricular node]],<ref>[http://www.merriam-webster.com/medical/junctional%20rhythm Merriam-Webster dictionary > Junctional rhythm] Retrieved September 2010</ref> the "junction" between atria and ventricles.
'''Junctional rhythm''' describes an abnormal [[heart rhythm]] resulting from impulses coming from a locus of tissue in the area of the [[atrioventricular node]], the "junction" between atria and ventricles. Junctional rhythm can be classified into junction escape rhythm, accelerated junctional rhythm, junctional bradycardia, and junctional tachycardia. The junctional rhythm can be originated by many medications that affect the sinoatrial node and make the atrioventricular node an ectopic impulses foci. Many conditions as well causes junctional rhythm by creating new pacemaker instead of the sinoatrial node. In junctional rhythm, the heart beats rate are not controlled by the sinoatrial node. The new pacemaker in the junctional rhythm is the atrioventricular node. Common causes of junctional rhythm include [[acute MI]], [[Acute rheumatic fever]], [[Antiarrhythmic agents|antiarrhythmic agents,]] [[beta-blockers]], [[calcium channel blockers]], [[Complete heart block|Complete heart block,]] [[Conduction system disease]], [[Digitalis toxicity]], [[Diphtheria]], Healthy response during sleep in patients with [[heightened vagal tone]], [[Heart surgery]] particularly [[valve replacement]] or surgery for [[congenital heart disease]], [[Ischemic heart disease]], [[Lyme disease]], [[NSTEMI]], [[Sick sinus syndrome]], [[Sinus arrest]], Chest trauma, Radiation therapy, Collagen vascular disease, Myocarditis, Clonidine, Reserpine, Adenosine, and Cimetidine. In the United States, the prevalence of junctional rhythm is 166 in 100,000 individuals with sinus node dysfunction. If left untreated, junctional rhythm can lead to syncope and other severe complications. Patients presenting with juncitonal rhythm disease should be asked properly for history of other cardiac conditions as heart failure and sick sinus syndrome. Symptoms of junctional rhythm can be non specific and includes syncope, dizziness, and faitgue. Physical examination findings of junctional rhythm include pulsating veins and canon a waves in case the right atrium contracting against a closed tricuspid valve. Electrocardiogram may show [[QRS complexes]] are narrow as conduction down the [[His bundle]] is normal. The junctional rate may be slow (40-60 beats per minute) in which case the rhythm is referred to as [[junctional bradycardia]]. The junctional rate may be rapid in which case the rhythm is referred to as a [[junctional tachycardia]]. Asymptomatic patients with only juncitonal rhythm and no other cardiac conditions do not require further management. The rhythm here is due to increased vagal tone only. Patients with sinus node dysfunction should be managed cautiously as the pulse originating from other foci keeps the heart rate. Patients with junctional rhythm due to digoxin toxicity are given atropine and digoxin specific antibody. In children, symptomatic patients can undergo percutaneous radiofrequency ablation. Pacemaker is indicated for patients with sick sinus syndrome and complete AV block.


==Classification==
==Classification==
* Junctional rhythm can be classified according to the rate of the heart rate as the following:<ref name="pmid1529897">{{cite journal| author=Spodick DH| title=Normal sinus heart rate: sinus tachycardia and sinus bradycardia redefined. | journal=Am Heart J | year= 1992 | volume= 124 | issue= 4 | pages= 1119-21 | pmid=1529897 | doi=10.1016/0002-8703(92)91012-p | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=1529897  }}</ref><ref name="pmid871100">{{cite journal| author=Thery C, Gosselin B, Lekieffre J, Warembourg H| title=Pathology of sinoatrial node. Correlations with electrocardiographic findings in 111 patients. | journal=Am Heart J | year= 1977 | volume= 93 | issue= 6 | pages= 735-40 | pmid=871100 | doi=10.1016/s0002-8703(77)80070-7 | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=871100  }}</ref><ref name="pmid23612425">{{cite journal| author=Dobrzynski H, Anderson RH, Atkinson A, Borbas Z, D'Souza A, Fraser JF | display-authors=etal| title=Structure, function and clinical relevance of the cardiac conduction system, including the atrioventricular ring and outflow tract tissues. | journal=Pharmacol Ther | year= 2013 | volume= 139 | issue= 2 | pages= 260-88 | pmid=23612425 | doi=10.1016/j.pharmthera.2013.04.010 | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=23612425  }}</ref>
===Junctional Rhythm===
*The junctional rate is normal.
=== Junction escape rhythm: ===
* The junctional rate is about 40-60 beats per minute.
=== Accelerated junctional rhythm: ===
* The juncitonal rate can be accelerated (60-100 beats per minute).
===Junctional Bradycardia===
===Junctional Bradycardia===
*The junctional rate may be slow (40-60 beats per minute) in which case the rhythm is referred to as [[junctional bradycardia]]
*The junctional rate may be slow (40-60 beats per minute) in which case the rhythm is referred to as [[junctional bradycardia]].
===Junctional Rhythm===
*The junctional rate is normal
===Junctional Tachycardia===
===Junctional Tachycardia===
*The junctional rate may be rapid in which case the rhythm is referred to as a [[junctional tachycardia]]
 
*The junctional rate may be rapid in which case the rhythm is referred to as a [[junctional tachycardia]].


==Pathophysiology==
==Pathophysiology==
Under normal conditions, the heart's [[sinoatrial node]] determines the rate by which the organ beats - in other words, it is the heart's "pacemaker." The electrical activity of [[sinus rhythm]] originates in the sinoatrial node and depolarizes the atria. Current then passes from the atria through the [[bundle of His]], from which it travels along [[Purkinje fibers]] to reach and depolarize the ventricles. This sinus rhythm is important because it ensures that the heart's atria reliably contract before the ventricles.


In junctional rhythm, however, the sinoatrial node does not control the heart's rhythm - this can happen in the case of a block in conduction somewhere along the pathway described above. When this happens, the heart's [[atrioventricular node]] takes over as the pacemaker.<ref> eMedicine:"Junctional Rhythms" http://www.emedicine.com/MED/topic1212.htm </ref>. In the case of a junctional rhythm, the atria will actually still contract before the ventricles; however, this does not happen by the normal pathway and instead is due to retrograde conduction (conduction comes from the ventricles or from the AV node into and through the atria).<ref> medical dictionary http://medical-dictionary.thefreedictionary.com/retrograde+conduction</ref>.
=== Physiology ===
 
* The sinoatrial node in the heart is the pacemaker that determine the rate of the heart beats. The electrical impulse starts from the sinoatrial node then travels through the atria. It continues through the bundle of his, Purkinje fibers, and the ventricles ending one heart beat.<ref>[http://www.merriam-webster.com/medical/junctional%20rhythm Merriam-Webster dictionary > Junctional rhythm] Retrieved September 2010</ref><ref name="pmid20797495">{{cite journal| author=Kim D, Shinohara T, Joung B, Maruyama M, Choi EK, On YK | display-authors=etal| title=Calcium dynamics and the mechanisms of atrioventricular junctional rhythm. | journal=J Am Coll Cardiol | year= 2010 | volume= 56 | issue= 10 | pages= 805-12 | pmid=20797495 | doi=10.1016/j.jacc.2010.03.070 | pmc=3050609 | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=20797495  }}</ref>
*This sinus rhythm indicates the atria normally contracts before the ventricles.
*
 
=== Pathogenesis ===
 
*The junctional rhythm can be originated by many medications that affect the sinoatrial node and make the atrioventricular node an ectopic impulses foci. Many conditions as well causes junctional rhythm by creating new pacemaker instead of the sinoatrial node.<ref name="pmid29130502">{{cite journal| author=Silvestri NJ, Ismail H, Zimetbaum P, Raynor EM| title=Cardiac involvement in the muscular dystrophies. | journal=Muscle Nerve | year= 2018 | volume= 57 | issue= 5 | pages= 707-715 | pmid=29130502 | doi=10.1002/mus.26014 | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=29130502  }}</ref>
*In junctional rhythm, the heart beats rate are not controlled by the sinoatrial node. The new pacemaker in the junctional rhythm is the atrioventricular node.<ref> eMedicine:"Junctional Rhythms" http://www.emedicine.com/MED/topic1212.htm </ref>
* The atria contracts before the ventricles but from a different signal. The impulse contracting the atria comes from the ventricles not the normal impulse coming from the sinoatrial node.<ref> medical dictionary http://medical-dictionary.thefreedictionary.com/retrograde+conduction</ref><ref name="pmid236124252">{{cite journal| author=Dobrzynski H, Anderson RH, Atkinson A, Borbas Z, D'Souza A, Fraser JF | display-authors=etal| title=Structure, function and clinical relevance of the cardiac conduction system, including the atrioventricular ring and outflow tract tissues. | journal=Pharmacol Ther | year= 2013 | volume= 139 | issue= 2 | pages= 260-88 | pmid=23612425 | doi=10.1016/j.pharmthera.2013.04.010 | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=23612425  }}</ref>
*Junctional tacycardia:<ref name="pmid21954877">{{cite journal| author=Liu CF, Ip JE, Lin AC, Lerman BB| title=Mechanistic heterogeneity of junctional ectopic tachycardia in adults. | journal=Pacing Clin Electrophysiol | year= 2013 | volume= 36 | issue= 1 | pages= e7-10 | pmid=21954877 | doi=10.1111/j.1540-8159.2011.03214.x | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=21954877  }}</ref><ref name="pmid288385493">{{cite journal| author=Di Biase L, Gianni C, Bagliani G, Padeletti L| title=Arrhythmias Involving the Atrioventricular Junction. | journal=Card Electrophysiol Clin | year= 2017 | volume= 9 | issue= 3 | pages= 435-452 | pmid=28838549 | doi=10.1016/j.ccep.2017.05.004 | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=28838549  }}</ref>
**Occurs when the atrioventricular node becomes the pacemaker and spreads impulse in a rapid pattern.
**It takes place when the myocardial tissue is inflammed and ischemic as in patients undergo a heart surgery.  


==Causes==
==Causes==
===[[Junctional bradycardia]]===
 
*[[Acute MI]]
* Common causes of junctional rhythm include the following diseases and medications:<ref name="pmid206067902">{{cite journal| author=Trappe HJ| title=Tachyarrhythmias, bradyarrhythmias and acute coronary syndromes. | journal=J Emerg Trauma Shock | year= 2010 | volume= 3 | issue= 2 | pages= 137-42 | pmid=20606790 | doi=10.4103/0974-2700.62112 | pmc=2884444 | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=20606790  }}</ref>
*[[Acute rheumatic fever]]
**[[Acute MI]]
*[[Antiarrhythmic agents]]
**[[Acute rheumatic fever]]
*[[Beta-blockers]]
**[[Antiarrhythmic agents]]
*[[Calcium channel blockers]]
**[[Beta-blockers]]
*[[Complete heart block]]
**[[Calcium channel blockers]]
*[[Conduction system disease]]
**[[Complete heart block]]
*[[Digitalis toxicity]]
**[[Conduction system disease]]
*[[Diphtheria]]
**[[Digitalis toxicity]]
*Healthy response during sleep in patients with [[heightened vagal tone]]
**[[Diphtheria]]
*[[Heart surgery]] particularly [[valve replacement]] or surgery for [[congenital heart disease]]
**Healthy response during sleep in patients with [[heightened vagal tone]]
**[[Heart surgery]] particularly [[valve replacement]] or surgery for [[congenital heart disease]]
**[[Ischemic heart disease]]
**[[Lyme disease]]
**[[NSTEMI]]
**[[Sick sinus syndrome]]
**[[Sinus arrest]]
**[[Sinus bradycardia]]
**[[STEMI]] particularly inferior MI involving the [[posterior descending artery]] causing ischemia of the [[AV node]] due to poor perfusion in the [[AV nodal artery]]
** Chest trauma                                                           
** Radiation therapy
** Collagen vascular disease
** Myocarditis
** Clonidine
** Reserpine
** Adenosine
** Cimetidine
** Antiarrhythmics class I to IV
** Lithium
** Amitriptyline
** Neuromuscular disorder
** X-linked muscular dystrophy
** Familial disorder
** Vasovagal simulation (endotracheal suctioning)
** Carotid sinus hypersensitivity
** Opioids
** Cannabinoids
** Isoproterenol infusion
** Hypothyroidism
** Sleep apnea
** Hypoxia
** Intracranial hypertension
** Hyperkalemia
** Anorexia nervosa
** Amyloidosis
** Pericarditis
** Rheumatic fever
** Repair of congenital heart disease
** Inherited channelopathy
 
== Differentiating Junctional Rhythm from other diseases ==
 
* Junctional rhythm must be differentiated from other diseases that cause abnormal cardiac electrical conduction.
 
<br />
{| class="wikitable"
|+
! colspan="2" align="center" style="background:#4479BA; color: #FFFFFF;" + |Arrhythmia
! align="center" style="background:#4479BA; color: #FFFFFF;" + |Rhythm
! align="center" style="background:#4479BA; color: #FFFFFF;" + |Rate
! align="center" style="background:#4479BA; color: #FFFFFF;" + |P wave
! align="center" style="background:#4479BA; color: #FFFFFF;" + |PR Interval
! align="center" style="background:#4479BA; color: #FFFFFF;" + |QRS Complex
! align="center" style="background:#4479BA; color: #FFFFFF;" + |Response to Maneuvers
! align="center" style="background:#4479BA; color: #FFFFFF;" + |Epidemiology
! align="center" style="background:#4479BA; color: #FFFFFF;" + |Co-existing Conditions
|-
! colspan="2" |Junctional rhythm<ref name="pmid6177443" /><ref name="pmid206067902" /><br />
!
*Regular
!
*40 - 60
!
*Normal
 
*
!
!
!
!
*Prevalence: 166 in 100,000 individuals with sinus node dysfunction in the united.
!
|-
! rowspan="3" |Atrioventricular block<ref name="pmid311250962">{{cite journal| author=Kerola T, Eranti A, Aro AL, Haukilahti MA, Holkeri A, Junttila MJ et al.| title=Risk Factors Associated With Atrioventricular Block. | journal=JAMA Netw Open | year= 2019 | volume= 2 | issue= 5 | pages= e194176 | pmid=31125096 | doi=10.1001/jamanetworkopen.2019.4176 | pmc=6632153 | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=31125096  }}</ref>
![[First degree AV block|First degree]] <ref name="pmid8734740">{{cite journal| author=Barold SS| title=Indications for permanent cardiac pacing in first-degree AV block: class I, II, or III? | journal=Pacing Clin Electrophysiol | year= 1996 | volume= 19 | issue= 5 | pages= 747-51 | pmid=8734740 | doi=10.1111/j.1540-8159.1996.tb03355.x | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=8734740  }}</ref><ref name="pmid15233485">{{cite journal| author=Upshaw CB| title=Comparison of the prevalence of first-degree atrioventricular block in African-American and in Caucasian patients: an electrocardiographic study III. | journal=J Natl Med Assoc | year= 2004 | volume= 96 | issue= 6 | pages= 756-60 | pmid=15233485 | doi= | pmc=2568382 | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=15233485  }}</ref>
|
* Regular
|
|
* Normal
|
* Prolonged PR interval (>200 msec)
|
* Less than 0.12 seconds, consistent, and normal in morphology.
|
* No treatment required
 
<br />
|
* Prevalence: 650 to 1600 per 100,000 individuals in the united states.
| rowspan="3" |<br />
 
*[[Heart failure]]
*[[Coronary heart disease]]
*[[Cardiomyopathy]]
*[[Sarcoidosis]]
*[[Lyme disease]]
* Defenerative muscle disorders as [[Lev's disease]] and [[Lenegre's disease]].
* Overly active [[vagus nerve]].
|-
![[Second degree AV block|Second degree]]<ref name="pmid2191578">{{cite journal| author=Zehender M, Meinertz T, Keul J, Just H| title=ECG variants and cardiac arrhythmias in athletes: clinical relevance and prognostic importance. | journal=Am Heart J | year= 1990 | volume= 119 | issue= 6 | pages= 1378-91 | pmid=2191578 | doi=10.1016/s0002-8703(05)80189-9 | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=2191578  }}</ref><ref name="pmid1176840">{{cite journal| author=Friedman HS, Gomes JA, Haft JI| title=An analysis of Wenckebach periodicity. | journal=J Electrocardiol | year= 1975 | volume= 8 | issue= 4 | pages= 307-15 | pmid=1176840 | doi=10.1016/s0022-0736(75)80003-3 | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=1176840  }}</ref>
|
* Regular irregular
|
|
* Normal
|
* Mobtiz I: Progressive PR prolongation
*Mobitz II: Normal PR interval
|QRS is normal but dropped as the following:
 
* Mobitz I: QRS complex is dropped after a progressive lengthening of PR
* Mobitz II: QRS complex is dropped after a normal PR
|
* Can be reversed by using a pacemaker.
|
* Prevalence: 3 per 100,000 individuals in the united states.
|-
![[Third degree AV block|Third degree]]<ref name="pmid14297523">{{cite journal |vauthors=OSTRANDER LD, BRANDT RL, KJELSBERG MO, EPSTEIN FH |title=ELECTROCARDIOGRAPHIC FINDINGS AMONG THE ADULT POPULATION OF A TOTAL NATURAL COMMUNITY, TECUMSEH, MICHIGAN |journal=Circulation |volume=31 |issue= |pages=888–98 |date=June 1965 |pmid=14297523 |doi=10.1161/01.cir.31.6.888 |url=}}</ref><ref name="pmid16236932">{{cite journal |vauthors=Movahed MR, Hashemzadeh M, Jamal MM |title=Increased prevalence of third-degree atrioventricular block in patients with type II diabetes mellitus |journal=Chest |volume=128 |issue=4 |pages=2611–4 |date=October 2005 |pmid=16236932 |doi=10.1378/chest.128.4.2611 |url=}}</ref>
|
* Regular
|
|
* Normal but no relationship between P wave and the QRS.
* More P waves than the QRS complexes.
|
* Varies
|
* Normal QRS
|
* Can be reversed by using a pacemaker.
|
* The prevalence: 20 per 100,000 individuals worldwide.
|-
! colspan="2" |'''Atrial Fibrillation (AFib)<ref name="pmid24837984">{{cite journal |vauthors=Lankveld TA, Zeemering S, Crijns HJ, Schotten U |title=The ECG as a tool to determine atrial fibrillation complexity |journal=Heart |volume=100 |issue=14 |pages=1077–84 |date=July 2014 |pmid=24837984 |doi=10.1136/heartjnl-2013-305149 |url=}}</ref><ref name="pmid22518390">{{cite journal |vauthors=Harris K, Edwards D, Mant J |title=How can we best detect atrial fibrillation? |journal=J R Coll Physicians Edinb |volume=42 Suppl 18 |issue= |pages=5–22 |date=2012 |pmid=22518390 |doi=10.4997/JRCPE.2012.S02 |url=}}</ref>'''
|
* Irregularly irregular
|
* On a 10-second 12-lead [[The electrocardiogram|EKG]] strip, multiply number of [[QRS complexes]] by 6
|
* Absent
*Fibrillatory waves
|
* Absent
|
* Less than 0.12 seconds, consistent, and normal in morphology in the absence of aberrant conduction
|
* Does not break with [[adenosine]] or [[vagal maneuvers]]
|
* 2.7–6.1 million people in the United States have AFib
* 2% of people younger than age 65 have AFib, while about 9% of people aged 65 years or older have AFib
|
* Elderly
* Following [[Coronary artery bypass surgery|bypass surgery]]
*[[Mitral valve disease]]
*[[Hyperthyroidism]]
*[[Diabetes mellitus|Diabetes]]
*[[Heart failure]]
*[[Ischemic heart disease]]
*[[Ischemic heart disease]]
*[[Lyme disease]]
*[[Chronic kidney disease]]
*[[NSTEMI]]
* Heavy [[alcohol]] use
*[[Sick sinus syndrome]]
* Left chamber enlargement
*[[Sinus arrest]]
|-
*[[Sinus bradycardia]]
! colspan="2" |'''[[Atrial Flutter]]'''<ref name="pmid28835836">{{cite journal |vauthors=Cosío FG |title=Atrial Flutter, Typical and Atypical: A Review |journal=Arrhythm Electrophysiol Rev |volume=6 |issue=2 |pages=55–62 |date=June 2017 |pmid=28835836 |pmc=5522718 |doi=10.15420/aer.2017.5.2 |url=}}</ref>
*[[STEMI]] particularly inferior MI involving the [[posterior descending artery]] causing ischemia of the [[AV node]] due to poor perfusion in the [[AV nodal artery]]
|
* Regular or Irregular
|
* 75 (4:1 block), 100 (3:1 block) and 150 (2:1 block) beats per minute (bpm), but 150 is more common
|
* Sawtooth pattern of P waves at 250 to 350 bpm
*Biphasic deflection in V1
|
* Varies depending upon the magnitude of the block, but is short
|
* Less than 0.12 seconds, consistent, and normal in morphology
|
* Conduction may vary in response to drugs and maneuvers dropping the rate from 150 to 100 or to 75 bpm
|
*[[Incidence]]: 88 per 100,000 individuals
|
*[[Elderly]]
*[[Alcohol]]
|-
! colspan="2" |'''[[Atrioventricular nodal reentry tachycardia]] ([[AV nodal reentrant tachycardia|AVNRT]])<ref name="pmid27617092">{{cite journal |vauthors=Katritsis DG, Josephson ME |title=Classification, Electrophysiological Features and Therapy of Atrioventricular Nodal Reentrant Tachycardia |journal=Arrhythm Electrophysiol Rev |volume=5 |issue=2 |pages=130–5 |date=August 2016 |pmid=27617092 |pmc=5013176 |doi=10.15420/AER.2016.18.2 |url=}}</ref><ref name="pmid20458824">{{cite journal |vauthors=Letsas KP, Weber R, Siklody CH, Mihas CC, Stockinger J, Blum T, Kalusche D, Arentz T |title=Electrocardiographic differentiation of common type atrioventricular nodal reentrant tachycardia from atrioventricular reciprocating tachycardia via a concealed accessory pathway |journal=Acta Cardiol |volume=65 |issue=2 |pages=171–6 |date=April 2010 |pmid=20458824 |doi=10.2143/AC.65.2.2047050 |url=}}</ref>'''<ref name="urlAtrioventricular Nodal Reentry Tachycardia (AVNRT) - StatPearls - NCBI Bookshelf">{{cite web |url=https://www.ncbi.nlm.nih.gov/books/NBK499936/ |title=Atrioventricular Nodal Reentry Tachycardia (AVNRT) - StatPearls - NCBI Bookshelf |format= |work= |accessdate=}}</ref><ref name="pmid25196716">{{cite journal |vauthors=Schernthaner C, Danmayr F, Strohmer B |title=Coexistence of atrioventricular nodal reentrant tachycardia with other forms of arrhythmias |journal=Med Princ Pract |volume=23 |issue=6 |pages=543–50 |date=2014 |pmid=25196716 |pmc=5586929 |doi=10.1159/000365418 |url=}}</ref>
|
* Regular
|
* 140-280 bpm
|
*Slow-Fast AVNRT:
**Pseudo-S wave in leads II, III, and AVF
**Pseudo-R' in lead V1.
*Fast-Slow AVNRT
**[[P waves]] between the [[QRS complex|QRS]] and [[T waves]] (QRS-P-T complexes)
*Slow-Slow AVNRT
**Late [[P waves]] after a [[QRS complex|QRS]]
**Often appears as [[atrial tachycardia]].
*Inverted, superimposed on or buried within the [[QRS complex]] (pseudo R prime in V1/pseudo S wave in inferior leads)
|
* Absent ([[P wave]] can appear after the QRS complex and before the T wave, and in atypical AVNRT, the [[P wave]] can appear just before the [[QRS complex]])
|
* Less than 0.12 seconds, consistent, and normal in morphology in the absence of aberrant conduction
*[[QRS complex alternans|QRS alternans]] may be present
|
* May break with [[adenosine]] or [[vagal maneuvers]]
|
* 60%-70% of all [[supraventricular tachycardias]]
|
*[[Structural heart disease]]
*[[Atrial tachyarrhythmias]]
|-
! colspan="2" |'''[[Multifocal atrial tachycardia|Multifocal Atrial Tachycardia]]<ref name="pmid2570520">{{cite journal |vauthors=Scher DL, Arsura EL |title=Multifocal atrial tachycardia: mechanisms, clinical correlates, and treatment |journal=Am. Heart J. |volume=118 |issue=3 |pages=574–80 |date=September 1989 |pmid=2570520 |doi=10.1016/0002-8703(89)90275-5 |url=}}</ref><ref name="pmid11884328">{{cite journal |vauthors=Goodacre S, Irons R |title=ABC of clinical electrocardiography: Atrial arrhythmias |journal=BMJ |volume=324 |issue=7337 |pages=594–7 |date=March 2002 |pmid=11884328 |pmc=1122515 |doi=10.1136/bmj.324.7337.594 |url=}}</ref>'''
|
* Irregular
|
*[[Atrial]] rate is > 100 beats per minute
|
* Varying morphology from at least three different foci
* Absence of one dominant atrial pacemaker, can be mistaken for [[atrial fibrillation]] if the [[P waves]] are of low amplitude
|
* Variable [[PR interval|PR intervals]], RR intervals, and PP intervals
|
* Less than 0.12 seconds, consistent, and normal in morphology
|
* Does not terminate with [[adenosine]] or [[vagal maneuvers]]
|
* 0.05% to 0.32% of [[electrocardiograms]] in general hospital admissions
|
*[[Elderly]]
*[[Chronic obstructive pulmonary disease]] ([[Chronic obstructive pulmonary disease|COPD]])
|-
! colspan="2" |'''Paroxysmal Supraventricular Tachycardia'''
|
* Regular
|
* 150 and 240 bpm
|
* Absent
* Hidden in [[QRS complex|QRS]]
|
* Absent
|
* Narrow complexes (< 0.12 s)
|
* Breaks with [[vagal maneuvers]], [[adenosine]], [[diving reflex]], [[oculocardiac reflex]]
|
*[[Prevalence]]: 0.023 per 100,000
|
*[[Alcohol]]
*[[Caffeine]]
*[[Nicotine]]
*[[Psychological stress]]
*[[Wolff-Parkinson-White syndrome]]
|-
! colspan="2" |'''[[Premature atrial contraction|Premature Atrial Contractrions]] ([[Premature atrial contraction|PAC]])'''<ref name="pmid26316525">{{cite journal |vauthors=Lin CY, Lin YJ, Chen YY, Chang SL, Lo LW, Chao TF, Chung FP, Hu YF, Chong E, Cheng HM, Tuan TC, Liao JN, Chiou CW, Huang JL, Chen SA |title=Prognostic Significance of Premature Atrial Complexes Burden in Prediction of Long-Term Outcome |journal=J Am Heart Assoc |volume=4 |issue=9 |pages=e002192 |date=August 2015 |pmid=26316525 |pmc=4599506 |doi=10.1161/JAHA.115.002192 |url=}}</ref><ref name="pmid18063110">{{cite journal |vauthors=Strasburger JF, Cheulkar B, Wichman HJ |title=Perinatal arrhythmias: diagnosis and management |journal=Clin Perinatol |volume=34 |issue=4 |pages=627–52, vii–viii |date=December 2007 |pmid=18063110 |pmc=3310372 |doi=10.1016/j.clp.2007.10.002 |url=}}</ref>
|
* Regular except when disturbed by premature beat(s)
|
* 80-120 bpm
|
* Upright
|
* > 0.12 second
* May be shorter than that in normal sinus rhythm (NSR) if the origin of PAC is located closer to the AV node
*Ashman’s Phenomenon:
**[[Premature atrial contraction|PAC]] displaying a [[right bundle branch block]] pattern
|
* Usually narrow (< 0.12 s)
|
* Breaks with [[vagal maneuvers]], [[adenosine]], [[diving reflex]], [[oculocardiac reflex]]
|
|
*[[Infant|Infants]]
*[[Cardiomyopathy]]
*[[Myocarditis]]
*[[Elderly]]
*[[Coronary artery disease]]
*[[Stroke]]
*Increased [[atrial natriuretic peptide]] ([[Atrial natriuretic peptide|ANP]])
*[[Hypercholesterolemia]]
|-
! colspan="2" |'''[[Wolff-Parkinson-White syndrome|Wolff-Parkinson-White Syndrome]]<ref name="pmid24982705">{{cite journal |vauthors=Rao AL, Salerno JC, Asif IM, Drezner JA |title=Evaluation and management of wolff-Parkinson-white in athletes |journal=Sports Health |volume=6 |issue=4 |pages=326–32 |date=July 2014 |pmid=24982705 |pmc=4065555 |doi=10.1177/1941738113509059 |url=}}</ref><ref name="pmid10597097">{{cite journal |vauthors=Rosner MH, Brady WJ, Kefer MP, Martin ML |title=Electrocardiography in the patient with the Wolff-Parkinson-White syndrome: diagnostic and initial therapeutic issues |journal=Am J Emerg Med |volume=17 |issue=7 |pages=705–14 |date=November 1999 |pmid=10597097 |doi=10.1016/s0735-6757(99)90167-5 |url=}}</ref>'''
|
* Regular
|
* Atrial rate is nearly 300 bpm and ventricular rate is at 150 bpm
|
* With [[orthodromic]] conduction due to a bypass tract, the [[P wave]] generally follows the [[QRS complex]], whereas in [[AVNRT]], the [[P wave]] is generally buried in the [[QRS complex]].
|
* Less than 0.12 seconds
|
* A [[delta wave]] and evidence of [[ventricular]] pre-excitation if there is conduction to the ventricle via ante-grade conduction down an accessory pathway
* A [[delta wave]] and pre-excitation may not be present because bypass tracts do not conduct ante-grade.
|
* May break in response to [[procainamide]], [[adenosine]], [[vagal maneuvers]]
|
* Worldwide [[prevalence]] of [[Wolff-Parkinson-White syndrome|WPW syndrome]] is 100 - 300 per 100,000
|
*[[Ebstein's anomaly]]
*[[Mitral valve prolapse]]: This cardiac disorder, if present, is associated with left-sided accessory pathways.
*[[Hypertrophic cardiomyopathy]]: This disorder is associated with familial/inherited form of [[Wolff-Parkinson-White syndrome|WPW syndrome]].
*[[Hypokalemic periodic paralysis]]
*[[Pompe disease]]
*[[Tuberous sclerosis]]
|}
 
==Epidemiology and Demographics==
 
=== Prevalence ===
 
* In the United States, the prevalence of junctional rhythm is 166 in 100,000 individuals with sinus node dysfunction.<ref name="pmid6177443">{{cite journal| author=Romhilt DW, Doyle M, Sagar KB, Hastillo A, Wolfgang TC, Lower RR | display-authors=etal| title=Prevalence and significance of arrhythmias in long-term survivors of cardiac transplantation. | journal=Circulation | year= 1982 | volume= 66 | issue= 2 Pt 2 | pages= I219-22 | pmid=6177443 | doi= | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=6177443  }}</ref>
 
=== Age ===
 
* The prevalence of junctional rhythm increases with age.
 
=== Gender ===
 
* Men and women are affected equally by juntional rhythm.
 
== Natural History, Complications and Prognosis ==
 
=== Natural History ===
 
* If left untreated, junctional rhythm can lead to syncope and other severe complications.<ref name="pmid28838549" />
 
=== Complications ===
 
* Complications of junctional rhythm include the following:<ref name="pmid28838549">{{cite journal| author=Di Biase L, Gianni C, Bagliani G, Padeletti L| title=Arrhythmias Involving the Atrioventricular Junction. | journal=Card Electrophysiol Clin | year= 2017 | volume= 9 | issue= 3 | pages= 435-452 | pmid=28838549 | doi=10.1016/j.ccep.2017.05.004 | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=28838549  }}</ref>
** Syncope
** Dizziness
** Fatigue
 
=== Prognosis ===
 
* Prognosis of junctional rhythm is good with the proper treatment.
 
== History and Symptoms ==
 
=== History ===
 
* Patients presenting with juncitonal rhythm disease should be asked properly for history of other cardiac conditions.
* Other cardiac conditions can affect the presentation of the patients. These cardiac conditions include:
** Heart failure
** Sick sinus syndrome
 
=== Symptoms ===
 
* Patients with juncitonal rhythm disease can be asymptomatic.
* Symptoms of junctional rhythm can be non specific and includes the following:
** Dizziness
** Fatigue
** Syncope
** Palpitaions
* Symptoms vary according to the underlying cause of junctional rhythm as the following:<ref name="pmid24988822">{{cite journal| author=Cools E, Missant C| title=Junctional ectopic tachycardia after congenital heart surgery. | journal=Acta Anaesthesiol Belg | year= 2014 | volume= 65 | issue= 1 | pages= 1-8 | pmid=24988822 | doi= | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=24988822  }}</ref><ref name="pmid288385492">{{cite journal| author=Di Biase L, Gianni C, Bagliani G, Padeletti L| title=Arrhythmias Involving the Atrioventricular Junction. | journal=Card Electrophysiol Clin | year= 2017 | volume= 9 | issue= 3 | pages= 435-452 | pmid=28838549 | doi=10.1016/j.ccep.2017.05.004 | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=28838549  }}</ref><ref name="pmid20606790">{{cite journal| author=Trappe HJ| title=Tachyarrhythmias, bradyarrhythmias and acute coronary syndromes. | journal=J Emerg Trauma Shock | year= 2010 | volume= 3 | issue= 2 | pages= 137-42 | pmid=20606790 | doi=10.4103/0974-2700.62112 | pmc=2884444 | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=20606790  }}</ref>
** Heart failure:
*** Shortness of breath
*** Lower extremities edema
** Valve dysfunction due to rheumatic fever:
*** Fever
*** Arthritis
*** Skin rash
 
== Physical Examination ==


===[[Junctional tachycardia]]===
* Common physical examination findings of junctional rhythm include the following:
*[[Acute MI]]
** Pulsating veins
*[[Digitalis]] toxicity.<ref name="urlJunctional Rhythm: Overview - eMedicine">{{cite web |url=http://emedicine.medscape.com/article/155146-overview |title=Junctional Rhythm: Overview - eMedicine |format= |work= |accessdate=2008-12-21}}</ref>
** Canon a waves in case the right atrium contracting against a closed tricuspid valve
*[[Heart surgery]]
** Regular heart rate in most of cases ranging from 40 to 60 beat per minute
*[[Isoproterenol infusion]]
*[[NSTEMI]]
*[[STEMI]]


==Diagnosis==
==Diagnosis==
Line 64: Line 443:


----
----
Shown below is an EKG with a a regular rhythm at a rate of about 43/minute. There are no P waves to be seen and the QRS duration is about 80 ms. This is a nodal rhythm.
Shown below is an EKG with a a regular rhythm at a rate of about 43/minute. There are no [[P waves]] to be seen and the [[QRS]] duration is about 80 ms. This is a nodal rhythm.


[[File:Nodal rhythm.jpg|center|500px]]
[[File:Nodal rhythm.jpg|center|500px]]


Copyleft images obtained courtesy of ECGpedia,  http://en.ecgpedia.org.
Copyleft images obtained courtesy of ECGpedia,  http://en.ecgpedia.org.
== Treatment ==
=== Medical therapy ===
* The underlying cause of junctional rhythm should be defined first before attempting treatment.
* Asymptomatic patients with only juncitonal rhythm and no other cardiac conditions do not require further management. The rhythm here is due to increased vagal tone only.
* Patients with sinus node dysfunction should be managed cautiously as the pulse originating from other foci keeps the heart rate.
* Patients with junctional rhythm due to digoxin toxicity are given atropine and digoxin specific antibody.<ref name="pmid2188752">{{cite journal| author=Antman EM, Wenger TL, Butler VP, Haber E, Smith TW| title=Treatment of 150 cases of life-threatening digitalis intoxication with digoxin-specific Fab antibody fragments. Final report of a multicenter study. | journal=Circulation | year= 1990 | volume= 81 | issue= 6 | pages= 1744-52 | pmid=2188752 | doi=10.1161/01.cir.81.6.1744 | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=2188752  }}</ref><ref name="pmid1626485">{{cite journal| author=Kelly RA, Smith TW| title=Recognition and management of digitalis toxicity. | journal=Am J Cardiol | year= 1992 | volume= 69 | issue= 18 | pages= 108G-118G; disc. 118G-119G | pmid=1626485 | doi=10.1016/0002-9149(92)91259-7 | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=1626485  }}</ref>
* Patients who do not respond to the usual medical therapy can be administered phenytoin.
=== Surgery ===
* In children, symptomatic patients can undergo percutaneous radiofrequency ablation. <ref name="pmid28823599">{{cite journal| author=Tuohy S, Saliba W, Pai M, Tchou P| title=Catheter ablation as a treatment of atrioventricular block. | journal=Heart Rhythm | year= 2018 | volume= 15 | issue= 1 | pages= 90-96 | pmid=28823599 | doi=10.1016/j.hrthm.2017.08.015 | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=28823599  }}</ref>
* Pacemaker:<ref name="pmid17420362">{{cite journal| author=Dobrzynski H, Boyett MR, Anderson RH| title=New insights into pacemaker activity: promoting understanding of sick sinus syndrome. | journal=Circulation | year= 2007 | volume= 115 | issue= 14 | pages= 1921-32 | pmid=17420362 | doi=10.1161/CIRCULATIONAHA.106.616011 | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=17420362  }}</ref>
** Indicated for patients with sick sinus syndrome and complete AV block.


==Related Chapters==
==Related Chapters==
Line 76: Line 471:


==References==
==References==
{{reflist|2}}
{{Reflist|2}}  


[[Category:Cardiology]]
[[Category:Cardiology]]

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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Ahmed Elsaiey, MBBCH [2]

See also: Junctional bradycardia for slow junctional rhythms, and junctional tachycardia for fast jucntional rhythms

Overview

Junctional rhythm describes an abnormal heart rhythm resulting from impulses coming from a locus of tissue in the area of the atrioventricular node, the "junction" between atria and ventricles. Junctional rhythm can be classified into junction escape rhythm, accelerated junctional rhythm, junctional bradycardia, and junctional tachycardia. The junctional rhythm can be originated by many medications that affect the sinoatrial node and make the atrioventricular node an ectopic impulses foci. Many conditions as well causes junctional rhythm by creating new pacemaker instead of the sinoatrial node. In junctional rhythm, the heart beats rate are not controlled by the sinoatrial node. The new pacemaker in the junctional rhythm is the atrioventricular node. Common causes of junctional rhythm include acute MI, Acute rheumatic fever, antiarrhythmic agents, beta-blockers, calcium channel blockers, Complete heart block, Conduction system disease, Digitalis toxicity, Diphtheria, Healthy response during sleep in patients with heightened vagal tone, Heart surgery particularly valve replacement or surgery for congenital heart disease, Ischemic heart disease, Lyme disease, NSTEMI, Sick sinus syndrome, Sinus arrest, Chest trauma, Radiation therapy, Collagen vascular disease, Myocarditis, Clonidine, Reserpine, Adenosine, and Cimetidine. In the United States, the prevalence of junctional rhythm is 166 in 100,000 individuals with sinus node dysfunction. If left untreated, junctional rhythm can lead to syncope and other severe complications. Patients presenting with juncitonal rhythm disease should be asked properly for history of other cardiac conditions as heart failure and sick sinus syndrome. Symptoms of junctional rhythm can be non specific and includes syncope, dizziness, and faitgue. Physical examination findings of junctional rhythm include pulsating veins and canon a waves in case the right atrium contracting against a closed tricuspid valve. Electrocardiogram may show QRS complexes are narrow as conduction down the His bundle is normal. The junctional rate may be slow (40-60 beats per minute) in which case the rhythm is referred to as junctional bradycardia. The junctional rate may be rapid in which case the rhythm is referred to as a junctional tachycardia. Asymptomatic patients with only juncitonal rhythm and no other cardiac conditions do not require further management. The rhythm here is due to increased vagal tone only. Patients with sinus node dysfunction should be managed cautiously as the pulse originating from other foci keeps the heart rate. Patients with junctional rhythm due to digoxin toxicity are given atropine and digoxin specific antibody. In children, symptomatic patients can undergo percutaneous radiofrequency ablation. Pacemaker is indicated for patients with sick sinus syndrome and complete AV block.

Classification

  • Junctional rhythm can be classified according to the rate of the heart rate as the following:[1][2][3]

Junctional Rhythm

  • The junctional rate is normal.

Junction escape rhythm:

  • The junctional rate is about 40-60 beats per minute.

Accelerated junctional rhythm:

  • The juncitonal rate can be accelerated (60-100 beats per minute).

Junctional Bradycardia

  • The junctional rate may be slow (40-60 beats per minute) in which case the rhythm is referred to as junctional bradycardia.

Junctional Tachycardia

Pathophysiology

Physiology

  • The sinoatrial node in the heart is the pacemaker that determine the rate of the heart beats. The electrical impulse starts from the sinoatrial node then travels through the atria. It continues through the bundle of his, Purkinje fibers, and the ventricles ending one heart beat.[4][5]
  • This sinus rhythm indicates the atria normally contracts before the ventricles.

Pathogenesis

  • The junctional rhythm can be originated by many medications that affect the sinoatrial node and make the atrioventricular node an ectopic impulses foci. Many conditions as well causes junctional rhythm by creating new pacemaker instead of the sinoatrial node.[6]
  • In junctional rhythm, the heart beats rate are not controlled by the sinoatrial node. The new pacemaker in the junctional rhythm is the atrioventricular node.[7]
  • The atria contracts before the ventricles but from a different signal. The impulse contracting the atria comes from the ventricles not the normal impulse coming from the sinoatrial node.[8][9]
  • Junctional tacycardia:[10][11]
    • Occurs when the atrioventricular node becomes the pacemaker and spreads impulse in a rapid pattern.
    • It takes place when the myocardial tissue is inflammed and ischemic as in patients undergo a heart surgery.

Causes

Differentiating Junctional Rhythm from other diseases

  • Junctional rhythm must be differentiated from other diseases that cause abnormal cardiac electrical conduction.


Arrhythmia Rhythm Rate P wave PR Interval QRS Complex Response to Maneuvers Epidemiology Co-existing Conditions
Junctional rhythm[13][12]
  • Regular
  • 40 - 60
  • Normal
  • Prevalence: 166 in 100,000 individuals with sinus node dysfunction in the united.
Atrioventricular block[14] First degree [15][16]
  • Regular
  • Normal
  • Prolonged PR interval (>200 msec)
  • Less than 0.12 seconds, consistent, and normal in morphology.
  • No treatment required
  • Prevalence: 650 to 1600 per 100,000 individuals in the united states.
Second degree[17][18]
  • Regular irregular
  • Normal
  • Mobtiz I: Progressive PR prolongation
  • Mobitz II: Normal PR interval
 QRS is normal but dropped as the following:
  • Mobitz I: QRS complex is dropped after a progressive lengthening of PR
  • Mobitz II: QRS complex is dropped after a normal PR
  • Can be reversed by using a pacemaker.
  • Prevalence: 3 per 100,000 individuals in the united states.
Third degree[19][20]
  • Regular
  • Normal but no relationship between P wave and the QRS.
  • More P waves than the QRS complexes.
  • Varies
  • Normal QRS
  • Can be reversed by using a pacemaker.
  • The prevalence: 20 per 100,000 individuals worldwide.
Atrial Fibrillation (AFib)[21][22]
  • Irregularly irregular
  • Absent
  • Fibrillatory waves
  • Absent
  • Less than 0.12 seconds, consistent, and normal in morphology in the absence of aberrant conduction
  • 2.7–6.1 million people in the United States have AFib
  • 2% of people younger than age 65 have AFib, while about 9% of people aged 65 years or older have AFib
Atrial Flutter[23]
  • Regular or Irregular
  • 75 (4:1 block), 100 (3:1 block) and 150 (2:1 block) beats per minute (bpm), but 150 is more common
  • Sawtooth pattern of P waves at 250 to 350 bpm
  • Biphasic deflection in V1
  • Varies depending upon the magnitude of the block, but is short
  • Less than 0.12 seconds, consistent, and normal in morphology
  • Conduction may vary in response to drugs and maneuvers dropping the rate from 150 to 100 or to 75 bpm
Atrioventricular nodal reentry tachycardia (AVNRT)[24][25][26][27]
  • Regular
  • 140-280 bpm
  • Slow-Fast AVNRT:
    • Pseudo-S wave in leads II, III, and AVF
    • Pseudo-R' in lead V1.
  • Fast-Slow AVNRT
  • Slow-Slow AVNRT
  • Inverted, superimposed on or buried within the QRS complex (pseudo R prime in V1/pseudo S wave in inferior leads)
  • Absent (P wave can appear after the QRS complex and before the T wave, and in atypical AVNRT, the P wave can appear just before the QRS complex)
  • Less than 0.12 seconds, consistent, and normal in morphology in the absence of aberrant conduction
  • QRS alternans may be present
Multifocal Atrial Tachycardia[28][29]
  • Irregular
  • Atrial rate is > 100 beats per minute
  • Varying morphology from at least three different foci
  • Absence of one dominant atrial pacemaker, can be mistaken for atrial fibrillation if the P waves are of low amplitude
  • Less than 0.12 seconds, consistent, and normal in morphology
Paroxysmal Supraventricular Tachycardia
  • Regular
  • 150 and 240 bpm
  • Absent
  • Hidden in QRS
  • Absent
  • Narrow complexes (< 0.12 s)
Premature Atrial Contractrions (PAC)[30][31]
  • Regular except when disturbed by premature beat(s)
  • 80-120 bpm
  • Upright
  • > 0.12 second
  • May be shorter than that in normal sinus rhythm (NSR) if the origin of PAC is located closer to the AV node
  • Ashman’s Phenomenon:
  • Usually narrow (< 0.12 s)
Wolff-Parkinson-White Syndrome[32][33]
  • Regular
  • Atrial rate is nearly 300 bpm and ventricular rate is at 150 bpm
  • Less than 0.12 seconds
  • A delta wave and evidence of ventricular pre-excitation if there is conduction to the ventricle via ante-grade conduction down an accessory pathway
  • A delta wave and pre-excitation may not be present because bypass tracts do not conduct ante-grade.

Epidemiology and Demographics

Prevalence

  • In the United States, the prevalence of junctional rhythm is 166 in 100,000 individuals with sinus node dysfunction.[13]

Age

  • The prevalence of junctional rhythm increases with age.

Gender

  • Men and women are affected equally by juntional rhythm.

Natural History, Complications and Prognosis

Natural History

  • If left untreated, junctional rhythm can lead to syncope and other severe complications.[34]

Complications

  • Complications of junctional rhythm include the following:[34]
    • Syncope
    • Dizziness
    • Fatigue

Prognosis

  • Prognosis of junctional rhythm is good with the proper treatment.

History and Symptoms

History

  • Patients presenting with juncitonal rhythm disease should be asked properly for history of other cardiac conditions.
  • Other cardiac conditions can affect the presentation of the patients. These cardiac conditions include:
    • Heart failure
    • Sick sinus syndrome

Symptoms

  • Patients with juncitonal rhythm disease can be asymptomatic.
  • Symptoms of junctional rhythm can be non specific and includes the following:
    • Dizziness
    • Fatigue
    • Syncope
    • Palpitaions
  • Symptoms vary according to the underlying cause of junctional rhythm as the following:[35][36][37]
    • Heart failure:
      • Shortness of breath
      • Lower extremities edema
    • Valve dysfunction due to rheumatic fever:
      • Fever
      • Arthritis
      • Skin rash

Physical Examination

  • Common physical examination findings of junctional rhythm include the following:
    • Pulsating veins
    • Canon a waves in case the right atrium contracting against a closed tricuspid valve
    • Regular heart rate in most of cases ranging from 40 to 60 beat per minute

Diagnosis

Electrocardiogram

  • The QRS complexes are narrow in so far as conduction down the His bundle is normal
  • The junctional rate may be slow (40-60 beats per minute) in which case the rhythm is referred to as junctional bradycardia
  • The junctional rate may be normal as shown in the tracing below
  • The junctional rate may be rapid in which case the rhythm is referred to as a junctional tachycardia
  • There is dissociation of the narrow complex QRS from an upright atrial p wave or the p wave is missing, or the p wave is retrograde (a retrograde p wave) due to retrograde conduction from the AV node back into the atrium.

EKG Examples

Shown below is an EKG depicting AV dissociation with variable timing of the p wave in relation to the QRS. A narrow complex junctional escape rhythm at 75 beats per minute is present.

Shown below is an EKG with a a regular rhythm at a rate of about 43/minute. There are no P waves to be seen and the QRS duration is about 80 ms. This is a nodal rhythm.

Copyleft images obtained courtesy of ECGpedia, http://en.ecgpedia.org.

Treatment

Medical therapy

  • The underlying cause of junctional rhythm should be defined first before attempting treatment.
  • Asymptomatic patients with only juncitonal rhythm and no other cardiac conditions do not require further management. The rhythm here is due to increased vagal tone only.
  • Patients with sinus node dysfunction should be managed cautiously as the pulse originating from other foci keeps the heart rate.
  • Patients with junctional rhythm due to digoxin toxicity are given atropine and digoxin specific antibody.[38][39]
  • Patients who do not respond to the usual medical therapy can be administered phenytoin.

Surgery

  • In children, symptomatic patients can undergo percutaneous radiofrequency ablation. [40]
  • Pacemaker:[41]
    • Indicated for patients with sick sinus syndrome and complete AV block.

Related Chapters

References

  1. ↑ Spodick DH (1992). "Normal sinus heart rate: sinus tachycardia and sinus bradycardia redefined". Am Heart J. 124 (4): 1119–21. doi:10.1016/0002-8703(92)91012-p. PMID 1529897.
  2. ↑ Thery C, Gosselin B, Lekieffre J, Warembourg H (1977). "Pathology of sinoatrial node. Correlations with electrocardiographic findings in 111 patients". Am Heart J. 93 (6): 735–40. doi:10.1016/s0002-8703(77)80070-7. PMID 871100.
  3. ↑ Dobrzynski H, Anderson RH, Atkinson A, Borbas Z, D'Souza A, Fraser JF; et al. (2013). "Structure, function and clinical relevance of the cardiac conduction system, including the atrioventricular ring and outflow tract tissues". Pharmacol Ther. 139 (2): 260–88. doi:10.1016/j.pharmthera.2013.04.010. PMID 23612425.
  4. ↑ Merriam-Webster dictionary > Junctional rhythm Retrieved September 2010
  5. ↑ Kim D, Shinohara T, Joung B, Maruyama M, Choi EK, On YK; et al. (2010). "Calcium dynamics and the mechanisms of atrioventricular junctional rhythm". J Am Coll Cardiol. 56 (10): 805–12. doi:10.1016/j.jacc.2010.03.070. PMC 3050609. PMID 20797495.
  6. ↑ Silvestri NJ, Ismail H, Zimetbaum P, Raynor EM (2018). "Cardiac involvement in the muscular dystrophies". Muscle Nerve. 57 (5): 707–715. doi:10.1002/mus.26014. PMID 29130502.
  7. ↑ eMedicine:"Junctional Rhythms" http://www.emedicine.com/MED/topic1212.htm
  8. ↑ medical dictionary http://medical-dictionary.thefreedictionary.com/retrograde+conduction
  9. ↑ Dobrzynski H, Anderson RH, Atkinson A, Borbas Z, D'Souza A, Fraser JF; et al. (2013). "Structure, function and clinical relevance of the cardiac conduction system, including the atrioventricular ring and outflow tract tissues". Pharmacol Ther. 139 (2): 260–88. doi:10.1016/j.pharmthera.2013.04.010. PMID 23612425.
  10. ↑ Liu CF, Ip JE, Lin AC, Lerman BB (2013). "Mechanistic heterogeneity of junctional ectopic tachycardia in adults". Pacing Clin Electrophysiol. 36 (1): e7–10. doi:10.1111/j.1540-8159.2011.03214.x. PMID 21954877.
  11. ↑ Di Biase L, Gianni C, Bagliani G, Padeletti L (2017). "Arrhythmias Involving the Atrioventricular Junction". Card Electrophysiol Clin. 9 (3): 435–452. doi:10.1016/j.ccep.2017.05.004. PMID 28838549.
  12. ↑ 12.0 12.1 Trappe HJ (2010). "Tachyarrhythmias, bradyarrhythmias and acute coronary syndromes". J Emerg Trauma Shock. 3 (2): 137–42. doi:10.4103/0974-2700.62112. PMC 2884444. PMID 20606790.
  13. ↑ 13.0 13.1 Romhilt DW, Doyle M, Sagar KB, Hastillo A, Wolfgang TC, Lower RR; et al. (1982). "Prevalence and significance of arrhythmias in long-term survivors of cardiac transplantation". Circulation. 66 (2 Pt 2): I219–22. PMID 6177443.
  14. ↑ Kerola T, Eranti A, Aro AL, Haukilahti MA, Holkeri A, Junttila MJ; et al. (2019). "Risk Factors Associated With Atrioventricular Block". JAMA Netw Open. 2 (5): e194176. doi:10.1001/jamanetworkopen.2019.4176. PMC 6632153 Check |pmc= value (help). PMID 31125096.
  15. ↑ Barold SS (1996). "Indications for permanent cardiac pacing in first-degree AV block: class I, II, or III?". Pacing Clin Electrophysiol. 19 (5): 747–51. doi:10.1111/j.1540-8159.1996.tb03355.x. PMID 8734740.
  16. ↑ Upshaw CB (2004). "Comparison of the prevalence of first-degree atrioventricular block in African-American and in Caucasian patients: an electrocardiographic study III". J Natl Med Assoc. 96 (6): 756–60. PMC 2568382. PMID 15233485.
  17. ↑ Zehender M, Meinertz T, Keul J, Just H (1990). "ECG variants and cardiac arrhythmias in athletes: clinical relevance and prognostic importance". Am Heart J. 119 (6): 1378–91. doi:10.1016/s0002-8703(05)80189-9. PMID 2191578.
  18. ↑ Friedman HS, Gomes JA, Haft JI (1975). "An analysis of Wenckebach periodicity". J Electrocardiol. 8 (4): 307–15. doi:10.1016/s0022-0736(75)80003-3. PMID 1176840.
  19. ↑ OSTRANDER LD, BRANDT RL, KJELSBERG MO, EPSTEIN FH (June 1965). "ELECTROCARDIOGRAPHIC FINDINGS AMONG THE ADULT POPULATION OF A TOTAL NATURAL COMMUNITY, TECUMSEH, MICHIGAN". Circulation. 31: 888–98. doi:10.1161/01.cir.31.6.888. PMID 14297523.
  20. ↑ Movahed MR, Hashemzadeh M, Jamal MM (October 2005). "Increased prevalence of third-degree atrioventricular block in patients with type II diabetes mellitus". Chest. 128 (4): 2611–4. doi:10.1378/chest.128.4.2611. PMID 16236932.
  21. ↑ Lankveld TA, Zeemering S, Crijns HJ, Schotten U (July 2014). "The ECG as a tool to determine atrial fibrillation complexity". Heart. 100 (14): 1077–84. doi:10.1136/heartjnl-2013-305149. PMID 24837984.
  22. ↑ Harris K, Edwards D, Mant J (2012). "How can we best detect atrial fibrillation?". J R Coll Physicians Edinb. 42 Suppl 18: 5–22. doi:10.4997/JRCPE.2012.S02. PMID 22518390.
  23. ↑ Cosío FG (June 2017). "Atrial Flutter, Typical and Atypical: A Review". Arrhythm Electrophysiol Rev. 6 (2): 55–62. doi:10.15420/aer.2017.5.2. PMC 5522718. PMID 28835836.
  24. ↑ Katritsis DG, Josephson ME (August 2016). "Classification, Electrophysiological Features and Therapy of Atrioventricular Nodal Reentrant Tachycardia". Arrhythm Electrophysiol Rev. 5 (2): 130–5. doi:10.15420/AER.2016.18.2. PMC 5013176. PMID 27617092.
  25. ↑ Letsas KP, Weber R, Siklody CH, Mihas CC, Stockinger J, Blum T, Kalusche D, Arentz T (April 2010). "Electrocardiographic differentiation of common type atrioventricular nodal reentrant tachycardia from atrioventricular reciprocating tachycardia via a concealed accessory pathway". Acta Cardiol. 65 (2): 171–6. doi:10.2143/AC.65.2.2047050. PMID 20458824.
  26. ↑ "Atrioventricular Nodal Reentry Tachycardia (AVNRT) - StatPearls - NCBI Bookshelf".
  27. ↑ Schernthaner C, Danmayr F, Strohmer B (2014). "Coexistence of atrioventricular nodal reentrant tachycardia with other forms of arrhythmias". Med Princ Pract. 23 (6): 543–50. doi:10.1159/000365418. PMC 5586929. PMID 25196716.
  28. ↑ Scher DL, Arsura EL (September 1989). "Multifocal atrial tachycardia: mechanisms, clinical correlates, and treatment". Am. Heart J. 118 (3): 574–80. doi:10.1016/0002-8703(89)90275-5. PMID 2570520.
  29. ↑ Goodacre S, Irons R (March 2002). "ABC of clinical electrocardiography: Atrial arrhythmias". BMJ. 324 (7337): 594–7. doi:10.1136/bmj.324.7337.594. PMC 1122515. PMID 11884328.
  30. ↑ Lin CY, Lin YJ, Chen YY, Chang SL, Lo LW, Chao TF, Chung FP, Hu YF, Chong E, Cheng HM, Tuan TC, Liao JN, Chiou CW, Huang JL, Chen SA (August 2015). "Prognostic Significance of Premature Atrial Complexes Burden in Prediction of Long-Term Outcome". J Am Heart Assoc. 4 (9): e002192. doi:10.1161/JAHA.115.002192. PMC 4599506. PMID 26316525.
  31. ↑ Strasburger JF, Cheulkar B, Wichman HJ (December 2007). "Perinatal arrhythmias: diagnosis and management". Clin Perinatol. 34 (4): 627–52, vii–viii. doi:10.1016/j.clp.2007.10.002. PMC 3310372. PMID 18063110.
  32. ↑ Rao AL, Salerno JC, Asif IM, Drezner JA (July 2014). "Evaluation and management of wolff-Parkinson-white in athletes". Sports Health. 6 (4): 326–32. doi:10.1177/1941738113509059. PMC 4065555. PMID 24982705.
  33. ↑ Rosner MH, Brady WJ, Kefer MP, Martin ML (November 1999). "Electrocardiography in the patient with the Wolff-Parkinson-White syndrome: diagnostic and initial therapeutic issues". Am J Emerg Med. 17 (7): 705–14. doi:10.1016/s0735-6757(99)90167-5. PMID 10597097.
  34. ↑ 34.0 34.1 Di Biase L, Gianni C, Bagliani G, Padeletti L (2017). "Arrhythmias Involving the Atrioventricular Junction". Card Electrophysiol Clin. 9 (3): 435–452. doi:10.1016/j.ccep.2017.05.004. PMID 28838549.
  35. ↑ Cools E, Missant C (2014). "Junctional ectopic tachycardia after congenital heart surgery". Acta Anaesthesiol Belg. 65 (1): 1–8. PMID 24988822.
  36. ↑ Di Biase L, Gianni C, Bagliani G, Padeletti L (2017). "Arrhythmias Involving the Atrioventricular Junction". Card Electrophysiol Clin. 9 (3): 435–452. doi:10.1016/j.ccep.2017.05.004. PMID 28838549.
  37. ↑ Trappe HJ (2010). "Tachyarrhythmias, bradyarrhythmias and acute coronary syndromes". J Emerg Trauma Shock. 3 (2): 137–42. doi:10.4103/0974-2700.62112. PMC 2884444. PMID 20606790.
  38. ↑ Antman EM, Wenger TL, Butler VP, Haber E, Smith TW (1990). "Treatment of 150 cases of life-threatening digitalis intoxication with digoxin-specific Fab antibody fragments. Final report of a multicenter study". Circulation. 81 (6): 1744–52. doi:10.1161/01.cir.81.6.1744. PMID 2188752.
  39. ↑ Kelly RA, Smith TW (1992). "Recognition and management of digitalis toxicity". Am J Cardiol. 69 (18): 108G–118G, disc. 118G-119G. doi:10.1016/0002-9149(92)91259-7. PMID 1626485.
  40. ↑ Tuohy S, Saliba W, Pai M, Tchou P (2018). "Catheter ablation as a treatment of atrioventricular block". Heart Rhythm. 15 (1): 90–96. doi:10.1016/j.hrthm.2017.08.015. PMID 28823599.
  41. ↑ Dobrzynski H, Boyett MR, Anderson RH (2007). "New insights into pacemaker activity: promoting understanding of sick sinus syndrome". Circulation. 115 (14): 1921–32. doi:10.1161/CIRCULATIONAHA.106.616011. PMID 17420362.

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