Non sustained ventricular tachycardia (NSVT)

• 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):

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)

Reference:

• 1) Buxton AE, Duc J, Berger EE, et al. Nonsustained ventricular tachycardia. Cardiol Clin. 2000;18:327-36
• 2) Yang JC, Wesley RC, Froelicher VF. Ventricular tachycardia during routine treadmill testing. Arch Intern Med. 1991;151(2):349-53
• 3) Dadkhah S et al. Exercise induced non-sustained ventricular tachycardia and indication for invasive management. Clin Med Insights Cardiol. 2011;5:121-6.
• 4) Katritsis DG, Camm AJ. Nonsustained ventricular tachycardia: where do we stand? Eur Heart J. 2004 Jul;25(13):1093-9.
• 5) NICE (May 2007).Cardiac resynchronisation therapy for the treatment of heart failure