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{{SI}}
{{Junctional bradycardia}}
{{CMG}}


{{SK}} junctional escape; junctional escape rhythm
'''For patient information, click [[Junctional bradycardia (patient information)|here]]'''
==Overview==
Junctional bradycardia is a slow (40 to 60 beats per minute) narrow complex escape rhythm that originates in the [[atrioventricular node]] to compensate for slow or impaired conduction of pacemaker activity in the atrium.


==Pathophysiology==
{{CMG}}; {{AE}} {{M.P}}
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.


==Causes==
{{SK}} Junctional escape; junctional escape rhythm
*[[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]]
*[[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]]


==Diagnosis==
==[[Junctional bradycardia overview|Overview]]==
===Symptoms===
Symptoms are more likely if the atrial rate is faster than the junctional rate (if [[AV dissociation]] or [[complete heart block]] is present) as compared with the scenario whereby the junctional rate is faster than the atrial rate. The following symptoms may be present:
*[[Dyspnea]]
*[[Fatigue]]
*[[Lightheadedness]]
*[[Palpitations]]
*[[Presyncope]]
*[[Reduced exercise tolerance]]
*[[Syncope]]


===Physical Examination===
==[[Junctional bradycardia historical perspective|Historical Perspective]]==
====Vitals====
=====Pulse=====
The pulse is regular at a rate of 40 to 60 beats per minute


====Neck====
==[[Junctional bradycardia classification|Classification]]==
*[[Cannon a waves]] may be present if there is delayed atrial contraction against a closed [[tricuspid valve]]


===Laboratory Studies===
==[[Junctional bradycardia pathophysiology|Pathophysiology]]==
Based upon the patient's history and demographics, consideration should be given to checking the following:
*[[Digoxin]] levels
*[[Lyme titers]] in patients where the disease is endemic


===Electrocardiography===
==[[Junctional bradycardia causes|Causes]]==
A 12 lead EKG should be obtained to evaluate the rhythm.  In so far as it may alter treatment, any co-existing rhythm disturbance that may have precipitated junctional bradycardia should be ascertained such as:


*[[AV dissociation]]
==[[Junctional bradycardia differential diagnosis|Differentiating Junctional bradycardia from other Disorders]]==
*[[Complete heart block]]
*[[Digitalis toxicity]]
*[[Sinus arrest]]
*[[Sinus bradycardia]]
*[[ST elevation MI]]


*The rate is 40-60 beats per minute
==[[Junctional bradycardia epidemiology and demographics|Epidemiology and Demographics]]==
*The rate is generally regular
*The [[QRS]] complex is narrow
*[[Retrograde p waves]] may be present due to retrograde conduction from the AV node. The p waves will be inverted in leads II and III.
*The [[p wave]] may be buried within the [[QRS]] complex and may not be discernable
*A slow [[AV nodal reentry tachycardia]] ([[AVNRT]]) should be excluded.


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==[[Junctional bradycardia risk factors|Risk Factors]]==


===Holter / Cardiac Event Monitoring===
==[[Junctional bradycardia natural history, complications and prognosis|Natural History, Complications and Prognosis]]==
A cardiac event monitor may be helpful in patients with transient symptoms or [[palpitations]] to exclude other rhythms such as [[ventricular tachycardia]].


===Electrophysiologic Studies===
==Diagnosis==
*There is normal conduction in the [[His bundle]], and the His-ventricular interval is normal.
[[Junctional bradycardia history and symptoms|History and Symptoms]] | [[Junctional bradycardia_physical_examination|Physical Examination]] | [[Junctional bradycardia laboratory findings|Laboratory Findings]] | [[Junctional bradycardia electrocardiogram|Electrocardiogram]] | [[Junctional bradycardia EKG examples|EKG Examples]] | [[Junctional bradycardia chest x-ray|Chest X Ray]] | [[Junctional bradycardia echocardiography|Echocardiography]] | [[Junctional bradycardia cardiac MRI|Cardiac MRI]] | [[Junctional bradycardia coronary angiography|Coronary Angiography]]
*Preceding each [[QRS]], there should be a [[His bundle]] depolarization
*AV conduction is variable
*VA conduction is variable


==Treatment==
==Treatment==
===Acute Management===
[[Junctional bradycardia medical therapy|Medical Therapy]] | [[Junctional bradycardia electrical cardioversion|Electrical Cardioversion]] | [[Junctional bradycardia ablation|Ablation]] | [[Junctional bradycardia surgery|Surgery]] | [[Junctional bradycardia primary prevention|Primary Prevention]] | [[Junctional bradycardia secondary prevention|Secondary Prevention]] | [[Junctional bradycardia cost effectiveness of therapy|Cost-Effectiveness of Therapy]] | [[Junctional bradycardia future or investigational therapies|Future or Investigational Therapies]]
*Avoid drugs that suppress the [[AV node]] as the junctional bradycardia may be the patient's only escape rhythm
 
*Treat symptomatic [[digitalis toxicity]] with [[atropine]] and [[digoxin immune Fab]] ([[Digibind]])
==Case Studies==
===Asymptomatic Patients===
[[Junctional bradycardia case study one|Case #1]]
*Among healthy patients with heightened vagal tone, no treatment is neccessary


===Symptomatic Patients===
==Related Chapters==
*Permanent pacemaker placement in indicated in symptomatic patients with:
* [[Junctional rhythm]]
:*[[Complete heart block]]
* [[Junctional tachycardia]]
:*High grade [[AV block]]
:*[[Sick sinus syndrome]]


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


[[Category:Disease]]
[[Category:Electrophysiology]]
[[Category:Cardiology]]
[[Category:Cardiology]]
[[Category:Electrophysiology]]
[[Category:Arrhythmia]]
[[Category:Emergency medicine]]
[[Category:Intensive care medicine]]
[[Category:Best pages]]
[[Category:Up-To-Date cardiology]]
[[Category:Up-To-Date]]
 
 
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Latest revision as of 22:21, 11 September 2013

Junctional bradycardia Microchapters

Home

Overview

Historical Perspective

Classification

Pathophysiology

Causes

Differentiating Junctional bradycardia from other Disorders

Epidemiology and Demographics

Risk Factors

Natural History, Complications and Prognosis

Diagnosis

History and Symptoms

Physical Examination

Laboratory Findings

Electrocardiogram

EKG Examples

Chest X Ray

Echocardiography

Cardiac MRI

Coronary Angiography

Treatment

Medical Therapy

Electrical Cardioversion

Ablation

Surgery

Primary Prevention

Secondary Prevention

Cost-Effectiveness of Therapy

Future or Investigational Therapies

Case Studies

Case #1

Junctional bradycardia On the Web

Most recent articles

Most cited articles

Review articles

CME Programs

Powerpoint slides

Images

Ongoing Trials at Clinical Trials.gov

US National Guidelines Clearinghouse

NICE Guidance

FDA on Junctional bradycardia

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to Hospitals Treating Junctional bradycardia

Risk calculators and risk factors for Junctional bradycardia

For patient information, click here

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Mugilan Poongkunran M.B.B.S [2]

Synonyms and keywords: Junctional escape; junctional escape rhythm

Overview

Historical Perspective

Classification

Pathophysiology

Causes

Differentiating Junctional bradycardia from other Disorders

Epidemiology and Demographics

Risk Factors

Natural History, Complications and Prognosis

Diagnosis

History and Symptoms | Physical Examination | Laboratory Findings | Electrocardiogram | EKG Examples | Chest X Ray | Echocardiography | Cardiac MRI | Coronary Angiography

Treatment

Medical Therapy | Electrical Cardioversion | Ablation | Surgery | Primary Prevention | Secondary Prevention | Cost-Effectiveness of Therapy | Future or Investigational Therapies

Case Studies

Case #1

Related Chapters


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