Lown-Ganong-Levine syndrome: Difference between revisions
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{{CMG}} {{AE}} {{Usman Ali Akbar}} | {{CMG}} {{AE}} {{Usman Ali Akbar}} | ||
==Overview== | ==Overview== | ||
Lown-Ganong-Levine Syndrome (LGL) is one of the [[Pre-excitation syndrome|pre-excitation syndromes]] that present with [[EKG]] findings of short PR interval, narrow/normal [[QRS complex]], and normal [[P wave]]. The presence of accessory bundles fibers such as James fiber leads to the development of abnormal conduction pathways. The LGL pattern was described in 1952 by Bernard Lown, William Francis Ganong, and Samual Levine. Patients present with a history of [[Palpitation|palpitations]], [[lightheadedness]], [[shortness of breath]], and sometimes chest pain. There is an increased risk of | Lown-Ganong-Levine Syndrome (LGL) is one of the [[Pre-excitation syndrome|pre-excitation syndromes]] that present with [[EKG]] findings of short PR interval, narrow/normal [[QRS complex]], and normal [[P wave]]. The presence of accessory bundles fibers such as James fiber leads to the development of abnormal conduction pathways. The LGL pattern was described in 1952 by Bernard Lown, William Francis Ganong, and Samual Levine. Patients present with a history of [[Palpitation|palpitations]], [[lightheadedness]], [[shortness of breath]], and sometimes chest pain. There is an increased risk of [[tachyarrhythmias]] and [[syncope]]. [[EKG]] is the principal modality of investigation for establishing a diagnosis. Usually, antiarrhythmics are given to prevent the development of tachyarrhythmias but recently [[radiofrequency ablation]] of the accessory pathway has been the main stray of treatment with a good prognosis. | ||
==Historical Perspective== | ==Historical Perspective== | ||
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|- | |- | ||
|1938 | |1938 | ||
|Clerc, Levy and Critesco in 1938 first reported cases in which there was occurence of frequent paroxysms of tachycardia. The EKG of such patients consist of a short PR interval and normal QRS interval | |Clerc, Levy and Critesco in 1938 first reported cases in which there was occurence of frequent paroxysms of [[tachycardia]]. The [[EKG]] of such patients consist of a short PR interval and normal QRS interval | ||
|- | |- | ||
|1946 | |1946 | ||
|Burch and Kimball hinted on existence of the atrio-Hisian pathway | |Burch and Kimball hinted on existence of the [[atrio-Hisian pathway]] | ||
|- | |- | ||
|1952 | |1952 | ||
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|- | |- | ||
|James Fibers | |James Fibers | ||
|They can be present as normal part of AV node but these fibers have been established as anatomic reason for LGL syndrome | |They can be present as a normal part of [[AV node]] but these fibers have been established as an anatomic reason for LGL syndrome | ||
|- | |- | ||
|Brechmacher fibers | |Brechmacher fibers | ||
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|- | |- | ||
|Intra-nodal bypass tracts | |Intra-nodal bypass tracts | ||
|Intra-nodal bypass tracts would allow the conduction of rapid action potential through AV node bypassing the other slow pathways. | |Intra-nodal bypass tracts would allow the conduction of rapid [[action potential]] through [[Atrioventricular node|AV node]] bypassing the other slow pathways. | ||
|} | |} | ||
==Pathophysiology== | ==Pathophysiology== | ||
*The pathophysiology of LGL syndrome has not yet been completely understood. | *The [[pathophysiology]] of LGL syndrome has not yet been completely understood. | ||
*Multiple theories have been proposed to suggest the mechanism of LGL. | *Multiple theories have been proposed to suggest the mechanism of LGL. | ||
*The current theory supporting the mechanism of LGL is that it may result from numerous underlying causes that involve junctional pathways that partially or wholly bypass the AV node with subsequent normal conduction down the bundle of His. | *The current theory supporting the mechanism of LGL is that it may result from numerous underlying causes that involve [[junctional pathways]] that partially or wholly bypass the [[Atrioventricular node|AV node]] with subsequent normal conduction down the bundle of His. | ||
*The three accessory pathways as discussed in classification has been proposed to be the main triggering factors for the development of LGL. | *The three [[accessory pathways]] as discussed in [[classification]] has been proposed to be the main triggering factors for the development of LGL. | ||
* Lown-Ganong-Levine pattern may occur include Brechenmacher fibers or intranodal bypass tracts and James Fibers. Brenchmacher fibers account for 0.03% of the patients presenting with LGL. | * Lown-Ganong-Levine pattern may occur include Brechenmacher fibers or intranodal bypass tracts and James Fibers. Brenchmacher fibers account for 0.03% of the patients presenting with LGL. | ||
*The intra-nodal bypass tracts allow the conduction of rapid action potential through AV-node bypassing the other slow pathways. | *The intra-nodal bypass tracts allow the conduction of rapid action potential through AV-node bypassing the other slow pathways. | ||
==Clinical Features== | ==Clinical Features== | ||
The clinical features of LGL overlap with other pre-excitation syndromes. Patient can present with following features. | The clinical features of LGL overlap with other [[Pre-excitation syndrome|pre-excitation syndromes]]. Patient can present with following features. | ||
* Palpitations | *[[Palpitations]] | ||
* Lightheadedness | *[[Lightheadedness]] | ||
* Shortness of breath | *[[Shortness of breath]] | ||
* Syncope | *[[Syncope]] | ||
* In case of an underlying cardiac structural defect, it can also present with chest pain or episodes of tachycardia. | * In case of an underlying cardiac structural defect, it can also present with [[chest pain]] or episodes of [[tachycardia]]. | ||
==Differentiating [disease name] from other Diseases== | ==Differentiating [disease name] from other Diseases== | ||
| Line 63: | Line 63: | ||
The differential diagnosis for Lown-Ganong-Levine includes | The differential diagnosis for Lown-Ganong-Levine includes | ||
*Supraventricular tachycardia | *[[Supraventricular tachycardia]] | ||
*Atrial fibrillation or flutter with a rapid ventricular response | *[[Atrial fibrillation]] or [[flutter]] with a rapid ventricular response | ||
*AV nodal reentry tachycardia | *[[AV nodal reentrant tachycardia|AV nodal reentry tachycardia]] | ||
*Wolf-Parkinson-White Syndrome | *[[Wolff-Parkinson-White syndrome|Wolf-Parkinson-White Syndrome]] | ||
==Epidemiology and Demographics== | ==Epidemiology and Demographics== | ||
* The Lown-Ganong-Levine pattern does not show an increased incidence in one particular sex or ethnic background. | * The Lown-Ganong-Levine pattern does not show an increased [[incidence]] in one particular sex or ethnic background. | ||
*In a retrospective study conducted by Bernard Lown, William Francis Ganong and Samual Levine 200 electrocardiograms (EKG) of 13500 patients showed EKG findings with prevalence of just over 1% | *In a [[Retrospective cohort study|retrospective study]] conducted by Bernard Lown, William Francis Ganong and Samual Levine 200 electrocardiograms (EKG) of 13500 patients showed EKG findings with prevalence of just over 1%. | ||
* | * | ||
| Line 97: | Line 97: | ||
=== Natural History === | === Natural History === | ||
*LGL syndrome can be asymptomatic or can present with palpitations, lightheadedness, shortness of breath, and syncope. In the case of congenital heart disease or genetic anomaly, it can also present as paroxysms of tachycardia or chest pain. | *LGL syndrome can be asymptomatic or can present with [[Palpitation|palpitations]], [[lightheadedness]], [[shortness of breath]], and [[syncope]]. In the case of congenital heart disease or genetic anomaly, it can also present as paroxysms of tachycardia or chest pain. | ||
=== Complications === | === Complications === | ||
*There is an increased risk of developing | *There is an increased risk of developing [[Tachyarrhythmias|tachyarrhythmias.]] | ||
*Certain medications such as sympathomimetics should be used with caution in the patients of LGL syndrome. Digitalis does not have any effect in LGL syndrome but it can slow conduction via the AV-node. This can prevent AVRT in these patients. | *Certain medications such as [[sympathomimetics]] should be used with caution in the patients of LGL syndrome. [[Digitalis]] does not have any effect in LGL syndrome but it can slow conduction via the AV-node. This can prevent [[AV reentrant tachycardia|AVRT]] in these patients. | ||
*Beta-blockers do not affect the accessory pathway directly but can slow conduction through AV node similar to digitalis. | *[[Beta-blockers]] do not affect the accessory pathway directly but can slow conduction through AV node similar to [[Digoxin|digitalis]]. | ||
=== Prognosis=== | === Prognosis=== | ||
There is an overall good prognosis in patients with LGL syndrome. Patients are usually asymptomatic but some can develop certain clinical features such as palpitations, shortness of breath, and occasional episodes of atrial fibrillation, atrial flutter, AVRT, and other tachyarrhythmias. They can also lead to the development of ventricular arrhythmias in rare cases. | There is an overall good prognosis in patients with LGL syndrome. Patients are usually asymptomatic but some can develop certain clinical features such as [[palpitations]], [[shortness of breath]], and occasional episodes of [[atrial fibrillation]], [[atrial flutter]], [[AV reentrant tachycardia|AVRT]], and other tachyarrhythmias. They can also lead to the development of ventricular arrhythmias in rare cases. | ||
== Diagnosis == | == Diagnosis == | ||
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Characteristic ECG findings of LGL syndrome are | Characteristic ECG findings of LGL syndrome are | ||
* Short [[PR interval]] (<120ms) | |||
* Normal [[P wave]] axis | |||
* Normal/narrow [[QRS complex|QRS morphology]] in the presence of paroxysmal tachyarrhythmia. | |||
=== Symptoms === | === Symptoms === | ||
*LGL syndrome is usually asymptomatic. | *LGL syndrome is usually asymptomatic. | ||
*Symptoms of LGL syndrome may include the following: | *Symptoms of LGL syndrome may include the following: | ||
:*palpitations | |||
:*chest pain | :*[[Palpitation|palpitations]] | ||
:*dizziness | :*[[chest pain]] | ||
:*lightheadedness | :*[[dizziness]] | ||
:*shortness of breath | :*[[lightheadedness]] | ||
:*Racing heart | :*[[shortness of breath]] | ||
:*[[Racing heart]] | |||
=== Physical Examination === | === Physical Examination === | ||
*Patients with LGL syndrome usually appear normal. | *Patients with LGL syndrome usually appear normal. | ||
*Physical examination findings are limited in LGL syndrome. | *Physical examination findings are limited in LGL syndrome. | ||
*During cardiac auscultation or palpation of peripheral pulses, there can be irregular rhythm. | *During cardiac auscultation or palpation of peripheral pulses, there can be [[Irregular heart rhythms|irregular rhythm]]. | ||
=== Laboratory Findings === | === Laboratory Findings === | ||
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==== ECG ==== | ==== ECG ==== | ||
The diagnosis of LGL syndrome can be made by the use of resting EKG. EKG finding usually shows | The diagnosis of LGL syndrome can be made by the use of resting [[The electrocardiogram|EKG]]. EKG finding usually shows | ||
*Short PR interval (<120ms) | *Short [[PR interval]] (<120ms) | ||
* Normal P wave axis | * Normal [[P wave]] axis | ||
* Normal/narrow QRS morphology in the presence of paroxysmal tachyarrhythmia. | * Normal/narrow [[QRS complex|QRS]] morphology in the presence of paroxysmal tachyarrhythmia. | ||
[[File:Lown–Ganong–Levine-syndrome-LGL.jpg|thumb|300px|none|ECG showing LGL syndrome with short PR interval, narrow QRS complex and normal P waves Source: LITFL <nowiki/>https://litfl.com/lown-ganong-levine-syndrome/ ]] | [[File:Lown–Ganong–Levine-syndrome-LGL.jpg|thumb|300px|none|ECG showing LGL syndrome with short PR interval, narrow QRS complex and normal P waves Source: LITFL <nowiki/>https://litfl.com/lown-ganong-levine-syndrome/ ]] | ||
<br /> | <br /> | ||
=== Other Diagnostic Studies === | === Other Diagnostic Studies === | ||
*Holter monitors or implantable loop recorders may provide insight to the underlying conductions abnormalities. | *[[Holter monitors]] or implantable loop recorders may provide insight to the underlying conductions abnormalities. | ||
== Treatment == | == Treatment == | ||
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*The mainstay of therapy for LGL syndrome is the use of antiarrhythmic medications to prevent tachyarrhythmias. | *The mainstay of therapy for LGL syndrome is the use of [[Antiarrhythmic agents|antiarrhythmic]] medications to prevent tachyarrhythmias. | ||
* Medications such as digitalis, beta-blockers, calcium channel blockers and Class I and III antiarrhythmic drugs have been used to slow down AV conduction and prevent AVRT and other arrhythmias. | * Medications such as [[digitalis]], [[beta-blockers]], [[calcium channel blockers]] and [[Antiarrhythmic drugs|Class I and III antiarrhythmic drugs]] have been used to slow down AV conduction and prevent [[AV reentrant tachycardia|AVRT]] and other arrhythmias. | ||
*Drugs like sotalol and amiodarone are under investigations and have promising effect in LGL syndrome but needs further studies. | *Drugs like [[sotalol]] and [[amiodarone]] are under investigations and have promising effect in LGL syndrome but needs further studies. | ||
=== Surgery === | === Surgery === | ||
Patients refractory to medical management can be managed by the use of radiofrequency catheter ablation as it has become primary treatment in various pre-excitation syndromes. This can be further implicated by the implantation of a permanent pacemaker. | Patients refractory to medical management can be managed by the use of [[radiofrequency catheter ablation]] as it has become primary treatment in various [[Pre-excitation syndrome|pre-excitation]] syndromes. This can be further implicated by the implantation of a permanent [[Artificial pacemaker|pacemaker.]] | ||
=== Prevention === | === Prevention === | ||
Revision as of 14:11, 20 August 2020
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] Associate Editor(s)-in-Chief: Usman Ali Akbar, M.B.B.S.[2]
Overview
Lown-Ganong-Levine Syndrome (LGL) is one of the pre-excitation syndromes that present with EKG findings of short PR interval, narrow/normal QRS complex, and normal P wave. The presence of accessory bundles fibers such as James fiber leads to the development of abnormal conduction pathways. The LGL pattern was described in 1952 by Bernard Lown, William Francis Ganong, and Samual Levine. Patients present with a history of palpitations, lightheadedness, shortness of breath, and sometimes chest pain. There is an increased risk of tachyarrhythmias and syncope. EKG is the principal modality of investigation for establishing a diagnosis. Usually, antiarrhythmics are given to prevent the development of tachyarrhythmias but recently radiofrequency ablation of the accessory pathway has been the main stray of treatment with a good prognosis.
Historical Perspective
| Year | Description |
|---|---|
| 1938 | Clerc, Levy and Critesco in 1938 first reported cases in which there was occurence of frequent paroxysms of tachycardia. The EKG of such patients consist of a short PR interval and normal QRS interval |
| 1946 | Burch and Kimball hinted on existence of the atrio-Hisian pathway |
| 1952 | The Lown-Ganong-Levine (LGL) pattern was described in 1952 by Bernard Lown, William Francis Ganong and Samual Levine. |
| 1961,1974 | In 1961 and subsequently in 1974 anatomic pathway was identified and reported by James and Brechemacher respectively. |
Classification
- LGL syndrome can be classified based on the accessory pathways into following categories
| Accessory Pathway | Description |
|---|---|
| James Fibers | They can be present as a normal part of AV node but these fibers have been established as an anatomic reason for LGL syndrome |
| Brechmacher fibers | These atrio-Hisian tracts are reported to have a frequency of 0.03 % and can be theoratically a cause of LGL syndrome |
| Intra-nodal bypass tracts | Intra-nodal bypass tracts would allow the conduction of rapid action potential through AV node bypassing the other slow pathways. |
Pathophysiology
- The pathophysiology of LGL syndrome has not yet been completely understood.
- Multiple theories have been proposed to suggest the mechanism of LGL.
- The current theory supporting the mechanism of LGL is that it may result from numerous underlying causes that involve junctional pathways that partially or wholly bypass the AV node with subsequent normal conduction down the bundle of His.
- The three accessory pathways as discussed in classification has been proposed to be the main triggering factors for the development of LGL.
- Lown-Ganong-Levine pattern may occur include Brechenmacher fibers or intranodal bypass tracts and James Fibers. Brenchmacher fibers account for 0.03% of the patients presenting with LGL.
- The intra-nodal bypass tracts allow the conduction of rapid action potential through AV-node bypassing the other slow pathways.
Clinical Features
The clinical features of LGL overlap with other pre-excitation syndromes. Patient can present with following features.
- Palpitations
- Lightheadedness
- Shortness of breath
- Syncope
- In case of an underlying cardiac structural defect, it can also present with chest pain or episodes of tachycardia.
Differentiating [disease name] from other Diseases
The differential diagnosis for Lown-Ganong-Levine includes
- Supraventricular tachycardia
- Atrial fibrillation or flutter with a rapid ventricular response
- AV nodal reentry tachycardia
- Wolf-Parkinson-White Syndrome
Epidemiology and Demographics
- The Lown-Ganong-Levine pattern does not show an increased incidence in one particular sex or ethnic background.
- In a retrospective study conducted by Bernard Lown, William Francis Ganong and Samual Levine 200 electrocardiograms (EKG) of 13500 patients showed EKG findings with prevalence of just over 1%.
Age
- There is currently insufficient data regarding age predilection of LGL syndrome.
Gender
- There is currently insufficient data regarding gender predilection of LGL syndrome.However, Lown in 1952 reported 70.9% of the 34 cases in women.
Race
- There is currently insufficient data regarding race predilection of LGL syndrome.].
Risk Factors
The data regarding the risk factors predisposing to LGL syndrome is insufficient. However following conditions or factor may lead to various pre-excitation syndromes.
- Presence of accessory bypass tracts
- High risk population for sudden cardiac death in Pre-excitation syndromes include
- Policemen
- Athletes
- Firemen
- Pilots
- Steelworkers
Natural History, Complications and Prognosis
Natural History
- LGL syndrome can be asymptomatic or can present with palpitations, lightheadedness, shortness of breath, and syncope. In the case of congenital heart disease or genetic anomaly, it can also present as paroxysms of tachycardia or chest pain.
Complications
- There is an increased risk of developing tachyarrhythmias.
- Certain medications such as sympathomimetics should be used with caution in the patients of LGL syndrome. Digitalis does not have any effect in LGL syndrome but it can slow conduction via the AV-node. This can prevent AVRT in these patients.
- Beta-blockers do not affect the accessory pathway directly but can slow conduction through AV node similar to digitalis.
Prognosis
There is an overall good prognosis in patients with LGL syndrome. Patients are usually asymptomatic but some can develop certain clinical features such as palpitations, shortness of breath, and occasional episodes of atrial fibrillation, atrial flutter, AVRT, and other tachyarrhythmias. They can also lead to the development of ventricular arrhythmias in rare cases.
Diagnosis
Diagnostic Criteria
Characteristic ECG findings of LGL syndrome are
- Short PR interval (<120ms)
- Normal P wave axis
- Normal/narrow QRS morphology in the presence of paroxysmal tachyarrhythmia.
Symptoms
- LGL syndrome is usually asymptomatic.
- Symptoms of LGL syndrome may include the following:
Physical Examination
- Patients with LGL syndrome usually appear normal.
- Physical examination findings are limited in LGL syndrome.
- During cardiac auscultation or palpation of peripheral pulses, there can be irregular rhythm.
Laboratory Findings
- There are no specific laboratory findings associated with LGL syndrome.
Imaging Findings
ECG
The diagnosis of LGL syndrome can be made by the use of resting EKG. EKG finding usually shows
- Short PR interval (<120ms)
- Normal P wave axis
- Normal/narrow QRS morphology in the presence of paroxysmal tachyarrhythmia.
Other Diagnostic Studies
- Holter monitors or implantable loop recorders may provide insight to the underlying conductions abnormalities.
Treatment
Medical Therapy
- The mainstay of therapy for LGL syndrome is the use of antiarrhythmic medications to prevent tachyarrhythmias.
- Medications such as digitalis, beta-blockers, calcium channel blockers and Class I and III antiarrhythmic drugs have been used to slow down AV conduction and prevent AVRT and other arrhythmias.
- Drugs like sotalol and amiodarone are under investigations and have promising effect in LGL syndrome but needs further studies.
Surgery
Patients refractory to medical management can be managed by the use of radiofrequency catheter ablation as it has become primary treatment in various pre-excitation syndromes. This can be further implicated by the implantation of a permanent pacemaker.
Prevention
- There are no primary preventive measures available for LGL syndrome.