Torsades de Pointes (Deep Dive R21)

Torsades de Pointes (TdP)



A type of polymorphic ventricular tachycardia that is inherently unstable and often quickly degrades into ventricular fibrillation. It usually occurs in the setting of a prolonged QT interval, which can either be genetic or acquired.



Treatment



* Defibrillation – per ACLS, ventricular tachycardia with a pulse should receive synchronized cardioversion. But in real life, the defibrillator often isn’t able to “sync” with TdP, forcing you to perform unsynchronized cardioversion (aka defibrillation).* IV Magnesium – treats and prevents TdP, even when magnesium levels are normal* Overdrive Pacing – by preventing bradycardia, we help prevent TdP (bradycardia prolongs the QT interval). * Electrical Overdrive Pacing – transcutaneous or transvenous pacemaker* Chemical Overdrive Pacing – beta agonist therapy (isoproterenol)* Lidocaine – anti-arrhythmic therapy that does not prolong QTc.* Fix underlying cause – congenital long QT syndrome, hypokalemia, hypocalcemia, medication induced (psych meds, anti-emetics, methadone, fluoroquinolones, many more)



Defibrillation and IV Magnesium are used for patients who are ACTIVELY in TdP. Once you shock/mag them into a stable rhythm, you can use Overdrive Pacing / Lidocaine / Treat Underlying Cause to PREVENT them from going back into TdP.