Junctional rhythm

WikiDoc Resources for Junctional rhythm
Articles
Most recent articles on Junctional rhythm Most cited articles on Junctional rhythm Review articles on Junctional rhythm Articles on Junctional rhythm in N Eng J Med, Lancet, BMJ
Media
Powerpoint slides on Junctional rhythm Images of Junctional rhythm Photos of Junctional rhythm Podcasts & MP3s on Junctional rhythm Videos on Junctional rhythm
Evidence Based Medicine
Cochrane Collaboration on Junctional rhythm Bandolier on Junctional rhythm TRIP on Junctional rhythm
Clinical Trials
Ongoing Trials on Junctional rhythm at Clinical Trials.gov Trial results on Junctional rhythm Clinical Trials on Junctional rhythm at Google
Guidelines / Policies / Govt
US National Guidelines Clearinghouse on Junctional rhythm NICE Guidance on Junctional rhythm NHS PRODIGY Guidance FDA on Junctional rhythm CDC on Junctional rhythm
Books
Books on Junctional rhythm
News
Junctional rhythm in the news Be alerted to news on Junctional rhythm News trends on Junctional rhythm
Commentary
Blogs on Junctional rhythm
Definitions
Definitions of Junctional rhythm
Patient Resources / Community
Patient resources on Junctional rhythm Discussion groups on Junctional rhythm Patient Handouts on Junctional rhythm Directions to Hospitals Treating Junctional rhythm Risk calculators and risk factors for Junctional rhythm
Healthcare Provider Resources
Symptoms of Junctional rhythm Causes & Risk Factors for Junctional rhythm Diagnostic studies for Junctional rhythm Treatment of Junctional rhythm
Continuing Medical Education (CME)
CME Programs on Junctional rhythm
International
Junctional rhythm en Espanol Junctional rhythm en Francais
Business
Junctional rhythm in the Marketplace Patents on Junctional rhythm
Experimental / Informatics
List of terms related to Junctional rhythm

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]

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.

Classification

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

• The junctional rate may be rapid in which case the rhythm is referred to as a junctional tachycardia

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.. 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)..

Causes

Junctional bradycardia

• 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

Junctional tachycardia

• Acute MI
• Digitalis toxicity.
• Heart surgery
• Isoproterenol infusion
• NSTEMI
• STEMI

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.

ECG Example

AV dissociation is present 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:

See also

• Junctional bradycardia
• Junctional tachycardia
• Junctional escape beat

References

Template:WikiDoc Sources