Monomorphic Ventricular Tachycardia



  • Monomorphic VT is a focal or reentrant ventricular rhythm that requires rapid assessment and management, due to its risk of haemodynamic instability and collapse.
    • Look For

    • Heart rate >100bpm
    • Regular rhythm (RR interval)
    • Broad QRS complexes >120ms
  • A left bundle branch morphology classically suggests a right ventricular focus of VT, while a right bundle morphology pattern suggests a left ventricular focus. A septal focus may manifest as either a left or right bundle branch morphology.
  • To find out how to distinguish VT from SVT with aberrancy, read the section called ‘distinguishing VT and SVT with aberrancy'.
    • Classification

    • Nonsustained VT - three or more ventricular beats at a rate of >100bpm, lasting less than 30 seconds, without haemodynamic instability
    • Sustained VT - a ventricular rhythm at a rate of >100bpm, lasting at least 30 seconds or with haemodynamic instability
    • Mechanisms

    • Monomorphic VT occurs most commonly in the context of a macro-reentrant pathway in a structurally abnormal heart. The rhythm may also be caused by a focal arrhythmogenic ventricular focus.
    • Causes of Monomorphic Ventricular Tachycardia

    • Myocardial infarction
    • Cardiomyopathy
    • Congestive cardiac failure
Last updated on December 29th, 2018
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