Idiopathic fascicular left ventricular tachycardia

Background

  • Also known as fascicular tachycardia, idiopathic fascicular left ventricular tachycardia (ILFVT), 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

  • 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.