A ventricular rhythm faster than 100 bpm lasting at least 30 seconds or requiring termination due to hemodynamic instability.
ECG findings include wide QRS complex (duration >120 milliseconds) at a rate greater than 100 bpm.
Patients may have a normal cardiac output or may be hemodynamically compromised during episodes of ventricular tachycardia (VT). Presence or absence of symptoms does not differentiate VT from supraventricular tachycardia (SVT).
Torsades de pointes (TdP): polymorphic VT with a characteristic twisting morphology occurring in the setting of QT interval prolongation.
Sustained VT is usually observed in ischemic cardiomyopathy, but idiopathic VT may also be observed in patients without structural heart disease.
Among patients with prior MI or nonischemic cardiomyopathy, VT is usually due to reentry involving regions of slowed conduction adjacent to scar.
Owing to the unpredictable and life-threatening nature of most etiologies of sustained VT, prophylactic implantable cardioverter defibrillator implantation is recommended in high-risk patients.
Sustained ventricular tachycardia (VT) is a ventricular rhythm faster than 100 bpm lasting at least 30 seconds or requiring termination earlier due to hemodynamic instability. VT is defined as a wide complex tachycardia (QRS 120 milliseconds or greater) that originates from one of the ventricles, and is not due to aberrant conduction (e.g., from bundle branch block), at a rate of 100 bpm or greater. "Idiopathic" VT occurs in the absence of apparent structural heart disease (e.g., prior MI, active ischemia, cardiomyopathy, valvular disease, arrhythmogenic right ventricular cardiomyopathy, left ventricular noncompaction, or other disorders of the myocardium), known channelopathy (e.g., long QT syndrome, Brugada syndrome, catecholaminergic polymorphic VT, short QT syndrome), drug toxicity, or electrolyte imbalance. VT can be described as monomorphic or polymorphic. Torsades de pointes is a polymorphic VT with a characteristic twisting morphology occurring in the setting of QT interval prolongation. Sustained VT usually results in hypotension and symptoms of weakness, syncope, or palpitations; however, the arrhythmia may be present in patients who are asymptomatic and normotensive.
Professor of Clinical Medicine
New York Medical College
Director, Cardiac Electrophysiology
Westchester Medical Center
SI is on the Biosense-Webster speakers' bureau. He receives honoraria from Biotronik for lectures and research grant support from Boston Scientific.
Prof Sei Iwai would like to gratefully acknowledge Dr Kenneth Stein and Dr Richard Keating, previous contributors to this monograph. KS declares he is an employee of and shareholder in Boston Scientific, a manufacturer of implantable cardioverter defibrillators and ablation catheters. RK declares that he has no competing interests.
The St. Luke's-Roosevelt Hospital Center
SM declares that he has no competing interests.
Kontos Professor of Cardiology
Medical College of Virginia
KAE declares that he has no competing interests.
Consultant Cardiologist and Electrophysiologist
John Radcliffe Hospital
KR declares that she has no competing interests.
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