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
• Re-entrant tachycardia seen typically in young patients without structural heart disease

Clinical Features

• young adult
• male (60-80%)
• 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
    • Paroxysmal supraventricular tachycardia (PSVT)
      • AV node re-entry tachycardia (AVNRT)
      • AV re-entry tachycardia (AVRT)
        • Lown-Ganong-Levine syndrome
        • Wolff–Parkinson–White syndrome
    • Junctional tachycardia
• Irregular
  • Multifocal atrial tachycardia (MAT)
  • Sinus tachycardia with frequent PACs, PJCs, PVCs
  • Atrial fibrillation
    • Atrial fibrillation with RVR
  • Atrial flutter with variable conduction
  • Digoxin Toxicity