Ventricular tachycardia (VT) is a potentially life-threatening heart rhythm disorder in which the ventricles (the heart’s lower pumping chambers) beat at an abnormally fast rate, typically 100 beats per minute or above, driven by rapid electrical impulses originating within the ventricular muscle rather than the normal sinus node.
VT is classified by duration: non-sustained VT terminates spontaneously within 30 seconds; sustained VT persists beyond 30 seconds and is a cardiac emergency. If the heart beats too fast to pump blood effectively, VT causes dizziness, loss of consciousness, or degenerates into ventricular fibrillation and cardiac arrest. Some VT is haemodynamically stable, allowing the person to remain conscious while the heart maintains partial output.
VT is most commonly associated with structural heart disease including dilated cardiomyopathy, hypertrophic cardiomyopathy, scarring from prior heart attack, and ARVC. It also occurs in inherited electrical conditions including Long QT Syndrome and Brugada Syndrome. Idiopathic VT arises in structurally normal hearts.
Acute management depends on stability: unstable VT requires immediate electrical cardioversion; stable VT may be treated with antiarrhythmic medication such as amiodarone. Long-term prevention includes ICD implantation, catheter ablation to destroy the VT circuit, and medication to suppress recurrence. VT episodes in ICD recipients may be treated painlessly by anti-tachycardia pacing before a shock is delivered.
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