Torsades de pointes

Torsades de pointes is a polymorphic ventricular tachycardia marked by QRS complexes that appear to twist around the electrocardiogram baseline. It is usually associated with prolonged ventricular repolarization and can deteriorate into ventricular fibrillation.

Long QT syndrome: A condition in which delayed ventricular repolarization prolongs the QT interval and can predispose to dangerous arrhythmias. The prolonged repolarization underlying torsades may result from inherited or acquired long QT syndrome.
Magnesium sulfate: A magnesium salt administered intravenously in medicine, including as first-line treatment for torsades de pointes. Intravenous magnesium is used to treat torsades, even when blood magnesium is normal.
Congenital long QT syndrome: An inherited disorder of cardiac ion channels that prolongs ventricular repolarization and increases arrhythmia risk. It is an inherited route to the prolonged QT interval associated with torsades.
Polymorphic ventricular tachycardia: A ventricular tachycardia in which successive QRS complexes vary in shape or direction. Torsades is the prolonged-QT-associated form of this broader rhythm category.
Syncope: A brief loss of consciousness caused by a temporary reduction in blood flow to the brain. A self-terminating torsades episode can abruptly reduce cerebral blood flow and cause fainting.
Early afterdepolarization: An abnormal depolarization during the prolonged action potential of a cardiac cell that can trigger an extra heartbeat. Early afterdepolarizations can initiate the premature beats that trigger torsades.
Electrical cardioversion: A synchronized electrical shock used to restore a more stable heart rhythm. It may be needed when torsades causes persistent instability and a pulse remains.
Acquired long QT syndrome: Prolongation of the QT interval caused by factors such as medications, electrolyte abnormalities, or illness. This acquired condition is a common setting for torsades.
Monomorphic ventricular tachycardia: A ventricular tachycardia with a largely consistent QRS shape from beat to beat. Its stable QRS morphology contrasts with torsades’ changing, twisting complexes.
Sudden cardiac death: Unexpected death from an abrupt loss of effective heart function, usually caused by a cardiac rhythm disturbance. Untreated torsades can progress to rhythms that cause sudden cardiac death.

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