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Ventricular tachycardia and sudden cardiac death
A wide-QRS tachycardia is VT until proven otherwise — especially in a patient with heart disease — and treatment follows pulse and stability: defibrillation without a pulse, cardioversion if unstable, and amiodarone or procainamide if stable.
Why it matters in the exam
Questions move between the emergency room and the clinic. In the emergency room: VT versus SVT with aberrant conduction (AV dissociation, capture beats and fusion beats favour VT), management of VF and cardiac arrest, and torsades de pointes treated with magnesium. In the clinic: who needs an ICD for primary or secondary prevention, and recognising inherited syndromes — long QT, Brugada and hypertrophic cardiomyopathy.
Candidates are also asked about the reversible causes to look for in every ventricular arrhythmia — acute ischaemia, hypokalaemia, hypomagnesaemia and QT-prolonging drugs — and about idiopathic VT in a normal heart (from the right-ventricular outflow tract, LBBB morphology with an inferior axis), which has a good prognosis and is treated with a beta-blocker or ablation. An ICD is not implanted when the cause is reversible and treated.
Key points
- Wide QRS = VT until proven otherwise.
- No pulse: defibrillation; unstable: synchronised cardioversion; stable: amiodarone or procainamide.
- Torsades: magnesium sulfate 2 g and stop QT-prolonging drugs.
- Secondary-prevention ICD after VT/VF without a reversible cause; primary prevention with EF 35% or less.
- Brugada: coved ST elevation in V1–V2, worse with fever; ICD after syncope or cardiac arrest.
Summary table
| Situation | Recognition | Acute treatment | Prevention |
|---|---|---|---|
| VF or pulseless VT | Cardiac arrest | Immediate defibrillation, CPR; adrenaline 1 mg and amiodarone 300 mg after the third shock | Secondary-prevention ICD if there is no reversible cause |
| Unstable VT with a pulse | Wide QRS, low blood pressure, confusion, chest pain | Synchronised electrical cardioversion | Treat the cause, ICD by indication |
| Stable VT | Wide, monomorphic QRS | Amiodarone 150 mg IV over 10 minutes, or procainamide; or elective cardioversion | Beta-blocker, ablation |
| Torsades de pointes | Polymorphic VT with a long QT | Magnesium sulfate 2 g IV, stop QT-prolonging drugs, correct potassium | Overdrive pacing or isoproterenol for recurrent episodes |
| Brugada syndrome | Coved ST elevation in V1–V2, unmasked by fever | Treat the fever | ICD after arrhythmic syncope or cardiac arrest |
| Primary prevention | EF 35% or less after 3 months of optimal therapy | — | ICD |
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Sources
- ESC Guidelines for the management of patients with ventricular arrhythmias and the prevention of sudden cardiac death, 2022 — Acute management, ICD indications and inherited arrhythmia syndromes
- European Resuscitation Council Guidelines, 2021 — Adult advanced life support
- Harrison's Principles of Internal Medicine, 21st edition (2022) — Ventricular Arrhythmias
Sources are given for further reading; the text is written afresh and not copied from them.
Reviewed by the Examqo AI Professor · 2026-11-02. The text may contain errors; when in doubt, check the source.