Idiopathic fascicular left ventricular tachycardia: Difference between revisions
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==Background== | ==Background== | ||
*Also known as | *Rare | ||
* | *Also known as narrow complex ventricular tachycardia, fascicular tachycardia, Belhassen-type VT, verapamil-sensitive VT, or intrafascicular tachycardia | ||
*Reentrant tachycardia seen typically in young patients without structural heart disease | |||
==Clinical Features== | ==Clinical Features== | ||
* | *Young adult | ||
* | *Male (60-80%)<ref>[https://www.escardio.org/Journals/E-Journal-of-Cardiology-Practice/Volume-9/Idiopathic-fascicular-left-ventricular-tachycardia], Reviriego, Sara Moreno. “Idiopathic Fascicular Left Ventricular Tachycardia.” European Society of Cardiology, European Society of Cardiology, 20 Dec. 2010. </ref> | ||
*[[ | *[[Palpitations]] | ||
*[[ | *[[Dizziness]] | ||
*[[ | *[[Syncope]] is infrequent | ||
==Differential Diagnosis== | ==Differential Diagnosis== | ||
{{Tachycardia (narrow) DDX}} | {{Tachycardia (narrow) DDX}} | ||
{{Palpitations DDX}} | |||
==Evaluation== | ==Evaluation== | ||
[[File:PMC1501077 ipej040098-01.png|thumb|ECG showing classic RBBB with leftward axis morphology suggestive of posterior fascicle origin.]] | |||
[[File:PMC2922873 ipej100357-07.png|thumb|Typical ECG showing RBBB (lead V1). Unlike outflow tract VT, however, leads AVl and AVr are both positive. A strong superior axis is noted, and the positive R wave dominates in lead one.]] | |||
[[File:PMC4573491 40001 2015 156 Fig1 HTML.png|thumb|ECG during ventricular tachycardia. ECG shows a monomorphic right bundle branch block tachycardia with a QRS duration of 120 ms (narrower than other forms of VT) right axis deviation, an appearance illustrative for fascicular ventricular tachycardia.]] | |||
[[File:PMC4573491 40001 2015 156 Fig2 HTML.png|thumb|ECG after amiodarone infusion. After slowing the heart rate with amiodarone, ECG shows captures (red arrow) and fusion beats (green arrow) suggestive of ventricular tachycardia.]] | |||
*Assume ventricular tachycardia until proven otherwise | |||
*Often misdiagnosed as SVT with aberrancy | |||
*Look for specific features of VT | |||
**fusion/capture beats | |||
**AV dissociation | |||
*ECG findings | |||
**Monomorphic VT | |||
**QRS duration <140 ms | |||
**RS interval 60-80 ms | |||
**Right Bundle Branch Block | |||
**Axis deviation depending on classification | |||
=== | ===Classification=== | ||
====Posterior fascicular VT==== | |||
*90-95% of cases | |||
*RBBB | |||
*Left axis deviation | |||
====Anterior fascicular VT==== | |||
*second most common | |||
*RBBB | |||
*Right axis deviation | |||
====Upper septal fascicular VT==== | |||
*rare | |||
*RBBB or LBBB | |||
*Normal axis | |||
==Management== | ==Management== | ||
| Line 22: | Line 50: | ||
====[[Synchronized Cardioversion]]==== | ====[[Synchronized Cardioversion]]==== | ||
*Adults: 0.5-1.0 J/kg | |||
*Pediatrics: 0.5-1 J/kg | |||
**If unsuccessful, increase to 2 J/kg | |||
*Consider sedation prior to cardioversion only if it will not significantly delay the procedure | |||
==Stable== | ===Stable=== | ||
== | ====[[Verapamil]]==== | ||
==[[ | |||
*10 mg over 1 min | *10 mg over 1 min | ||
** | **Only administer in stable patients with an established diagnosis of IFLVT | ||
====[[Digoxin Immune Fab]]==== | |||
*IFLVT as a result of [[Digoxin toxicity]] is responsive to digoxin immune Fab | |||
==Disposition== | ==Disposition== | ||
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==External Links== | ==External Links== | ||
*https://litfl.com/idiopathic-fascicular-left-ventricular-tachycardia/ | |||
==References== | ==References== | ||
<references/> | <references/> | ||
[[Category:Cardiology]] | |||
Latest revision as of 02:32, 27 November 2021
Background
- Rare
- Also known as narrow complex ventricular tachycardia, fascicular tachycardia, Belhassen-type VT, verapamil-sensitive VT, or intrafascicular tachycardia
- Reentrant tachycardia seen typically in young patients without structural heart disease
Clinical Features
- Young adult
- Male (60-80%)[1]
- Palpitations
- Dizziness
- Syncope is infrequent
Differential Diagnosis
Narrow-complex tachycardia
- Regular
- AV Node Independent
- Sinus tachycardia
- Atrial tachycardia (uni-focal or multi-focal)
- Atrial fibrillation
- Atrial flutter
- Idiopathic fascicular left ventricular tachycardia
- AV Node Dependent
- AV Node Independent
- Irregular
- Multifocal atrial tachycardia (MAT)
- Sinus tachycardia with frequent PACs, PJCs, PVCs
- Atrial fibrillation
- Atrial flutter with variable conduction
- Digoxin Toxicity
Palpitations
- Arrhythmias:
- Non-arrhythmic cardiac causes:
- Psychiatric causes:
- Drugs and Medications:
- Alcohol
- Caffeine
- Drugs of abuse (e.g. cocaine)
- Medications (e.g. digoxin, theophylline)
- Tobacco
- Misc
Evaluation
- Assume ventricular tachycardia until proven otherwise
- Often misdiagnosed as SVT with aberrancy
- Look for specific features of VT
- fusion/capture beats
- AV dissociation
- ECG findings
- Monomorphic VT
- QRS duration <140 ms
- RS interval 60-80 ms
- Right Bundle Branch Block
- Axis deviation depending on classification
Classification
Posterior fascicular VT
- 90-95% of cases
- RBBB
- Left axis deviation
Anterior fascicular VT
- second most common
- RBBB
- Right axis deviation
Upper septal fascicular VT
- rare
- RBBB or LBBB
- Normal axis
Management
Unstable
Synchronized Cardioversion
- Adults: 0.5-1.0 J/kg
- Pediatrics: 0.5-1 J/kg
- If unsuccessful, increase to 2 J/kg
- Consider sedation prior to cardioversion only if it will not significantly delay the procedure
Stable
Verapamil
- 10 mg over 1 min
- Only administer in stable patients with an established diagnosis of IFLVT
Digoxin Immune Fab
- IFLVT as a result of Digoxin toxicity is responsive to digoxin immune Fab