Torsades de pointes ("twisting of the points") is a form of polymorphic ventricular tachycardia characterized by a revolving QRS axis producing an undulating QRS amplitude that gives the tracing a ribbon-like appearance.
The usual presentation is syncope or sudden cardiac arrest.
Some patients may complain of dizziness, lightheadedness, or palpitations, particularly if they experience short bursts.
Some patients will present with recurrent syncope.
It may be fatal without prompt cardioversion. Without treatment, recurrence is common.
Can occur at any age. Generally associated with an underlying long QT interval, which may be congenital or acquired. Other risk factors include female sex, QT-prolonging medications, metabolic disturbance (especially hypokalemia or hypomagnesemia), myocardial ischemia, and bradycardia.
ICD10CM: I45.81 – Long QT syndrome
SNOMEDCT: 31722008 – Torsades de Pointes
Differential Diagnosis & Pitfalls
– Various supraventricular arrhythmias (eg, , , , , or ) may present with dizziness, lightheadedness, palpitations, and (less commonly) syncope. If there is aberrant ventricular conduction, it will produce a wide QRS complex tachycardia that may be difficult to distinguish from ventricular tachycardia, although the QRS complexes are generally monomorphic.
– Patients with an accessory atrioventricular (AV) conduction pathway can present with dizziness, lightheadedness, palpitations, or syncope due to atrioventricular reentrant tachycardia as well as atrial fibrillation or atrial flutter with rapid conduction down the accessory pathway, which can produce extremely rapid ventricular rates that can degenerate to ventricular fibrillation. Delta waves may be present on a baseline ECG.
– Hereditary channelopathy resulting in recurrent syncope or sudden cardiac arrest. Baseline ECG shows characteristic ST elevation and T-wave abnormality in the right precordial leads.
Catecholaminergic polymorphic – Voltage-gated ion channel mutation that causes polymorphic ventricular tachycardia resulting in dizziness, syncope, or sudden cardiac arrest triggered by exercise or emotional stress. The baseline ECG may be normal. Arrhythmias may be seen on treadmill testing.
Sinus node dysfunction – Prolonged sinus pauses or sinus exit block can cause dizziness, lightheadedness, and/or syncope. The arrhythmia may be sporadic and can be missed on a screening ECG. Longer term ECG monitoring may be necessary to make the diagnosis.
– Third-degree (complete) AV block produces severe bradycardia that can present as dizziness or syncope. It may be intermittent. ECG monitoring or invasive electrophysiologic testing may be necessary to make the diagnosis.
– The most common cause of syncope. There may be clues in the history, although structural heart disease and arrhythmia must be excluded. Tilt testing may also be helpful to establish the diagnosis.
– Prodromal symptoms (aura), tongue biting, urinary incontinence, tremors, convulsions, and postictal symptoms (eg, fatigue, confusion) are often present. An electroencephalogram (EEG) may be abnormal.
Structural heart disease – Valvular heart disease or severe cardiomyopathy may cause syncope, particularly during exertion, although other symptoms such as dyspnea, edema, orthopnea, and/or angina usually predominate.
Drug Reaction Data
Below is a list of drugs with literature evidence indicating an adverse association with this diagnosis. The list is continually updated through ongoing research and new medication approvals. Click on Citations to sort by number of citations or click on Medication to sort the medications alphabetically.