Idiopathic fascicular left ventricular tachycardia: Difference between revisions
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==Background==
==Background==
*Also known as fascicular tachycardia, idiopathic fascicular left ventricular tachycardia (ILFVT), Belhassen-type VT, verapamil-sensitive VT, or intrafascicular tachycardia
*Rare
*Re-entrant tachycardia seen typically in young patients without structural heart disease
*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  
*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>
*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]]
*[[Palpitations]]
*[[dizziness]]
*[[Dizziness]]
*[[syncope]] is infrequent
*[[Syncope]] is infrequent


==Differential Diagnosis==
==Differential Diagnosis==
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==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
*Assume ventricular tachycardia until proven otherwise
*Often misdiagnosed as SVT with aberrancy  
*Often misdiagnosed as SVT with aberrancy  
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===Stable===
===Stable===
====[[Verapamil]]====
====[[Verapamil]]====
*10 mg over 1 min
*10 mg over 1 min
**only administer in stable patients with an established diagnosis of IFLVT
**Only administer in stable patients with an established diagnosis of IFLVT


====Vagal Maneuvers====
====[[Digoxin Immune Fab]]====
*IFLVT does not usually respond to this treatment
*IFLVT as a result of [[Digoxin toxicity]] is responsive to digoxin immune Fab
 
====[[Adenosine]]====
*IFLVT does not usually respond to this treatment
 
====[[Beta Blockers]]====
*IFLVT does not usually respond to this treatment
 
====[[Lidocaine]]====
*IFLVT does not usually respond to this treatment


==Disposition==
==Disposition==
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==External Links==
==External Links==
 
*https://litfl.com/idiopathic-fascicular-left-ventricular-tachycardia/


==References==
==References==
<references/>
<references/>

Revision as of 21:40, 27 February 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

Differential Diagnosis

Narrow-complex tachycardia

Palpitations

Evaluation

ECG showing classic RBBB with leftward axis morphology suggestive of posterior fascicle origin.
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.
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.
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

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

Disposition

See Also

External Links

References

  1. ↑ [1], Reviriego, Sara Moreno. “Idiopathic Fascicular Left Ventricular Tachycardia.” European Society of Cardiology, European Society of Cardiology, 20 Dec. 2010.
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