The clinical approach to the patient with nonsustained ventricular tachycardia (NSVT) should always be considered within the particular clinical context in which the arrhythmia occurs. In the documented absence of heart disease, spontaneous NSVT does not carry any adverse prognostic significance. Exercise-induced NSVT may predict increased cardiac mortality. In ischaemic patients with a left ventricular ejection fraction (LVEF)<40%, NSVT has an adverse prognostic significance and electrophysiologic testing is indicated with a view to ICD implantation. In patients with LVEF>40% the independent prognostic significance of NSVT is unknown. The prognostic value of NSVT in patients with dilated cardiomyopathy is not known. NSVT in young patients with hypertrophic obstructive cardiomyopathy carries an adverse prognostic significance. The prognostic value of NSVT in conditions such as the long-QT syndromes, primary ventricular fibrillation, and Brugada syndrome, as well as in patients with hypertension and valvular disease, has not been established.