Torsades de pointes

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Overview

Torsades de pointes ('twisting of the points') is a form of polymorphic ventricular tachycardia
It is associated with long QT interval
It translates from French as “twisting of the tips”, describing the ECG characteristics. It looks like normal ventricular tachycardia on an ECG however there is an appearance that the QRS complex is twisting around the baseline.
- The height of the QRS complexes progressively get smaller, then larger then smaller and so on.

A prolonged QT interval is the ECG finding of prolonged repolarisation of the muscle cells in the heart after a contraction.
- Depolarisation is the electrical process that leads to the heart contraction.
- Repolarisation is a period of recovery before the heart muscle cells (myocytes) are ready to depolarise again.
Waiting a longer time for repolarisation can result in random spontaneous depolarisation in some areas of heart myocytes.
These abnormal spontaneous depolarisations prior to repolarisation are known as “afterdepolarisations”.
These depolarisations spread throughout the ventricle, leading to a ventricular contraction prior to proper repolarisation occurring.
When this occurs and the ventricles continue to stimulate recurrent contractions without normal repolarisation it is called Torsades de pointes.

METHCAT

Methadone

Erythromycin

Terfenadine

Haloperidol

Chloroquine/Citalopram

Amiodrone

Tricyclics

A - amiodarone

○ T - Terfenadine ○ T - tricyclics

○ H - Haloperidol ○ S - Sotalol

<aside> 💡 A prolonged QT interval is the ECG finding of prolonged repolarisation of the muscle cells in the heart after a contraction

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