An ectopic ventricular rhythm on ECG consisting of 3 or more consecutive, wide (duration ≥120 milliseconds) QRS complexes with a rate greater than 120 bpm, spontaneously resolving in less than 30 seconds.
Usually asymptomatic, although brief palpitations may sometimes be experienced. Symptoms in a patient with known nonsustained ventricular tachycardia (NSVT) are most often attributed to underlying cardiac disease rather than the arrhythmia itself.
Defined as a self-terminating event. No specific treatment indicated. Management is directed at any underlying heart condition.
Implantable cardioverter defibrillator (ICD) placement may be used for selected patients who have additional risk factors such as structural heart disease. Patients at risk for sudden cardiac death and who also have discordant contraction of left ventricular function may benefit from cardiac resynchronization therapy (CRT).
Prognosis dependent on presence or absence of cardiac disease. Left ventricular function in post-MI patients remains the most important prognostic tool for overall mortality and risk for sudden cardiac death.
No increase in mortality demonstrated in those patients without associated cardiac disease.
Nonsustained ventricular tachycardia (NSVT) is an ectopic ventricular rhythm with wide QRS complex (≥120 milliseconds), rate faster than 120 bpm, lasting for at least 3 beats that spontaneously resolves in less than 30 seconds.  It may occur in the absence of any underlying heart disease. However, it is more commonly associated with ischemic and nonischemic heart disease; known genetic disorders such as long QT syndrome, Brugada syndrome, and arrhythmogenic right ventricular cardiomyopathy; congenital heart disease; metabolic problems including drug toxicity; or electrolyte imbalance. 
Professor of Medicine
Mayo Medical School
Division of Cardiovascular Diseases
Department of Medicine
Mayo Clinic Florida
FK declares that he has no competing interests.
Professor Kusumoto would like to gratefully acknowledge Dr Ronald R. Butendieck Jr, a previous contributor to this monograph. RRB declares that he has no competing interests.
Adult Cardiovascular Fellowship
Department of Cardiology
Chicago Medical School (CMS) and affiliated hospitals
SS declares that he has no competing interests.
Consultant Cardiologist and Chair
Royal Brompton & Harefield NHS Trust
Hon. Senior Lecturer
VM declares that he has no competing interests.
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