View source for Idiopathic fascicular left ventricular tachycardia

==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%)<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==
{{Tachycardia (narrow) DDX}}
{{Palpitations DDX}}

==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==
===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

==Disposition==


==See Also==


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

==References==
<references/>

[[Category:Cardiology]]