Torsades de pointes

Torsades de pointes is a distinctive form of ventricular tachycardia, a rapid rhythm arising in the lower heart chambers, in which the electrocardiogram shows complexes twisting around the baseline. It develops against a lengthened QT interval, which may be inherited, as in congenital long QT syndrome, or acquired, most often through medicines. Implicated drug classes include antiarrhythmics, antipsychotics, antiemetics, antifungals and antimicrobials, while low potassium, calcium or magnesium, a slow heart rate, female sex, older age and structural heart disease add risk. Episodes may cause palpitations, dizziness or fainting, though many notice nothing; the rhythm is often brief but can degenerate into ventricular fibrillation and sudden cardiac death. Diagnosis needs an electrocardiogram captured during the event, with rhythm monitoring and blood chemistry tests. Treatment withdraws QT-prolonging drugs, corrects electrolyte imbalances and gives intravenous magnesium as first-line therapy, with electrical cardioversion for unstable patients and pacing for recurrent episodes.

Seek emergency care for chest pain or pressure lasting more than a few minutes, sudden breathlessness, fainting, or weakness or numbness of the face, arm or leg. See a doctor soon for palpitations, swollen ankles, breathlessness on exertion or a blood pressure reading that stays high. Call the local emergency number for any symptom that is sudden and severe. This page is a reference for healthcare professionals and does not replace an assessment.