Polymorphic Ventricular Tachycardia | Tachyarrhythmias - MedSchool
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Tachyarrhythmias
 
 
Tachyarrhythmias
 
 
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Polymorphic VT is a wide complex tachycardia with multiple QRS complex morphologies. This most commonly refers to torsade de pointes, however PVT also present in patients with acute myocardial infarction.
 

Polymorphic Ventricular Tachycardia

 
 
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Overview

  • Polymorphic VT is a wide complex tachycardia with multiple QRS complex morphologies. This most commonly refers to torsade de pointes, however PVT also present in patients with acute myocardial infarction.
    • Look For

    • Heart rate >100bpm
    • Irregular rhythm
    • Broad QRS complexes of varying amplitude and morphology
    • Causes of Polymorphic Ventricular Tachycardia

    • Torsade de pointes - due to prolonged QT
    • Non-torsades polymorphic VT - most commonly due to coronary ischaemia / infarction
  • Polymorphic VT other than torsade de pointes will have a normal QTc once reverted to sinus rhythm.

Torsade de Pointes

  • Torsades is a polymorphic VT that occurs as a result of a prolonged QT interval.
    • Look For

    • Polymorphic ventricular tachycardia with ‘twisting’ around the isoelectric line
    • Prolonged QT interval once reverted to sinus rhythm
    • Torsade de Pointes
       
    • Causes of Prolonged QT

    • Congenital

    • LQTS1 (triggered by exercise)
    • LQTS2 (triggered by stress and loud noises)
    • LQTS3 (triggered by sleep)
    • Others - LQTS4-6, Jervell and Lange-Nielsen syndrome
    • Drugs

    • Antiarrhythmics - amiodarone, sotalol, procainamide, quinidine
    • Antidepressants - amitryptiline, dothiepine, citalopram, escitalopram
    • Antipsychotics - risperidone, haloperidol, clozapine, droperidol, chlorpromazine
    • Antiemetics - ondansetron, domperidone
    • Macrolides - azithromycin, clarithromycin, erythromycin
    • Quinolones - ciprofloxacin, moxifloxacin
    • Antifungals - fluconazole, ketoconazole
    • Antimalarials - chloroquine, mefloquine
    • Anaesthetic gases – halothane, sevoflurane
    • Methadone
    • Others

    • Hypokalaemia
    • Hypomagnesaemia
    • Hypocalcaemia
    • Severe hypothermia
    • Severe bradycardia - sick sinus syndrome, complete heart block
    • Cardiovascular disease - tako-tsubo cardiomyopathy, MI, CCF
    • Cerebrovascular disease - intracranial / subarachnoid haemorrhage, stroke
    • Hypothyroidism
Last updated on December 29th, 2018
 
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