non sustained ventricular tachycardia (NSVT)

Last reviewed 01/2018

  • Non-sustained ventricular tachycardia (NSVT) is one of the most common problems encountered in modern clinical cardiology
    • the term, defined as 3 or more consecutive beats arising below the atrioventricular node with a rate 120 beats/min and lasting less than 30 s (1,2,3)

However, the diagnostic implications of exercise-induced non-sustained ventricular tachycardia (NSVT) are uncertain, especially as an isolated finding

  • VT can originate from left ventricle (LV)
  • there has been considerable debate in management of exercise induced NSVT

A classification of the significance of NSVT has been stated depending on clinical setting (4):

Clinical setting Significance
Apparently normal heart Random finding No adverse prognostic significance in the absence of occult pathology
During or postexercise May predict IHD and increased cardiac mortality

Ischemic heart disease

  • Acute MI <24 h
 No adverse prognostic significance

Ischemic heart disease

  • Acute MI >24 h
 Adverse prognostic significance
Chronic IHD with left ventricular ejection fraction (LVEF) >40% Prognostic significance unknown
Chronic IHD with LVEF <40% Adverse prognostic significance
dilated cardiomyopathy Independent prognostic significance not established, as opposed to LVEF
hypertrophic obstructive cardiomyopathy (HOCM) Probable adverse prognostic significance, especially in the young
Primary VF, congenital long-QT, Brugada syndrome, arrhythmogenic right ventricular dysplasia (ARVD), repaired congenital abnormalities, valvular disease, hypertension Prognostic significance unknown

How should one proceed when an asymptomatic exercised- induced NSVT with normal systolic function is identified (3)?

  • importance of this question arises from the fact that NSVT may be associated with an increased risk of SCD (sudden cardiac death). The goal of further workup is to identify those patients at risk for SCD so that appropriate therapy can be initiated.
    • first objective should be to identify structural heart disease (LV dysfunction, valvular heart disease, and ventricular hypertrophy)
      • in the absence of structural heart disease, NSVT carries a relatively low risk of SCD
        • NSVT in this setting is typically due to one of two things: ischemia or idiopathic VT
          • in patients with suspected CAD (coronary arterial disease), NSVT was associated with a slightly increased risk but was not as strong a predictor as wall motion abnormalities by echocardiography

  • in ischaemic patients with a left ventricular ejection fraction (LVEF) < NSVT has an adverse prognostic significance and electrophysiologic testing is indicated with a view to ICD implantation (5)

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