Mg in VT

Q: In Polymorphic ventricular tachycardia, intravenous (IV) magnesium sulfate (MgSo4) is of benefit even in patients with normal serum magnesium level.

A) True 

B) False

Answer: A

Polymorphic ventricular tachycardia (VT) is an unstable rhythm with a continuously varying QRS complex morphology in any recorded electrocardiographic (ECG) lead. When polymorphic VT occurs in the setting of QT prolongation in sinus rhythm, it is called torsades de pointes. It usually creates hemodynamic instability and requires cardioversion. In patients who are conscious and have recurrent episodes, IV magnesium sulfate is still the first-line of treatment. It treats polymorphic-VT and helps prevent a recurrence, even in patients with normal serum Mg levels.

The dose is 1-2 grams over 15 minutes in IVPB and can be followed by an intravenous drip. 

#cardiology

References:

1. Siraj TZ, Ganim I, Barker W, Abraham J, Landa E. Torsades de Pointes With a Normal Magnesium Level in the Setting of Short Bowel Syndrome. Cureus. 2021 Jul 29;13(7):e16743. doi: 10.7759/cureus.16743. PMID: 34513369; PMCID: PMC8405364.

2. Matsuura C, Kato T, Koyama K. Successful Management of Refractory Torsades De Pointes Due to Drug-Induced Long QT Syndrome Guided by Point-of-Care Monitoring of Ionized Magnesium. Cureus. 2021 Mar 17;13(3):e13939. doi: 10.7759/cureus.13939. PMID: 33880279; PMCID: PMC8051539.