Sustained ventricular tachycardia (VT) is defined as lasting greater than 30 seconds or symptomatic. Non-sustained is less than 30 seconds and asymptomatic.

There is a big difference in the management of sustained versus non-sustained VT. Sustained VT requires immediate attention with either cardioversion or medication therapy depending on the stability of the patient. Non-sustained VT is present in most patients with systolic heart failure and is usually asymptomatic.