Ventricular tachycardia
Ventricular tachycardia is three or more consecutive ventricular beats at over 100 per minute, a wide-complex tachycardia that is life-threatening when sustained. Any regular wide-complex tachycardia is ventricular tachycardia until proven otherwise: unstable patients are cardioverted or defibrillated, and long-term risk is managed with an implantable defibrillator.
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What this article covers
- Overview
Definition: ventricular tachycardia (VT) is three or more consecutive beats arising below the AV node at a rate over 100 per minute, producing a wide-complex tachycardia; it is nonsustained if under…
- Epidemiology
Most commonly arises from scar after prior myocardial infarction.
- Risk factors
Prior myocardial infarction and left ventricular scar (the dominant substrate).
- Pathophysiology
Scar-related reentry: surviving myocyte bundles within an infarct scar create a reentrant circuit, the commonest mechanism of monomorphic VT.
- Clinical features
Palpitations, presyncope, syncope, and chest pain.
- Differential diagnosis
Supraventricular tachycardia with aberrancy: wide-complex but supraventricular (supraventricular tachycardia).
- Diagnosis
Establish with an ECG showing a wide-complex tachycardia and apply criteria favoring a ventricular origin: the diagnostic basis is a 12-lead ECG demonstrating a wide-QRS tachycardia, with features…
- Management
First-line, treat by pulse and stability: defibrillate pulseless VT, and perform immediate synchronized cardioversion for sustained VT with hemodynamic instability.
- Complications
Sudden cardiac death from degeneration to ventricular fibrillation.
- Prognosis
Depends on the substrate and ventricular function, worse with low ejection fraction and scar.
- Prevention
ICD for secondary prevention and for primary prevention when ejection fraction is 35 percent or less.
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Related articles
- Ventricular fibrillation
Ventricular fibrillation is chaotic, disorganized ventricular electrical activity with no effective contraction, producing immediate loss of cardiac output and cardiac arrest. It is the leading shockable arrest rhythm, and survival depends on immediate CPR and defibrillation, followed by treatment of the cause and an ICD for secondary prevention.
- Sudden cardiac arrest
Sudden cardiac arrest is the abrupt cessation of cardiac function with loss of pulse and consciousness, most often from a ventricular tachyarrhythmia on a background of coronary disease. Survival depends on immediate CPR and defibrillation of shockable rhythms, followed by treatment of the cause and secondary prevention with an ICD.
- Premature ventricular contractions
Premature ventricular contractions are early wide-complex beats from an ectopic ventricular focus, extremely common and usually benign in structurally normal hearts. A high burden can cause a reversible cardiomyopathy, and PVCs in the setting of structural heart disease carry prognostic weight, so evaluation targets burden and underlying disease; management ranges from reassurance and trigger reduction to a beta-blocker for symptoms and catheter ablation for high-burden disease.
- Supraventricular tachycardia
Supraventricular tachycardia is any tachyarrhythmia arising at or above the AV node, usually a regular narrow-complex tachycardia. Acute management of a stable regular narrow-complex SVT is vagal maneuvers then adenosine; unstable patients receive synchronized cardioversion, and definitive therapy is catheter ablation.
- Wolff-Parkinson-White (WPW) syndrome
Wolff-Parkinson-White syndrome is ventricular pre-excitation via an accessory pathway plus symptomatic tachyarrhythmia, marked on the resting ECG by a short PR interval and a delta wave. Its danger is pre-excited atrial fibrillation, which can conduct rapidly to the ventricles and degenerate into ventricular fibrillation; AV nodal blockers are contraindicated in that setting, and catheter ablation of the pathway is curative.
- Torsades de pointes
Torsades de pointes is a polymorphic ventricular tachycardia occurring on a background of QT prolongation, with a characteristic twisting of QRS complexes around the baseline. Management is intravenous magnesium, correction of the underlying QT-prolonging cause, and rate acceleration by pacing or isoproterenol; unstable episodes are defibrillated.