This week we’ll be covering the LOMAGHI trial and use of magnesium in atrial fibrillation (AF) with RVR
Background: AF with RVR is a common arrhythmia encountered in the emergency department. Typical initial rate control agents include beta blockers (BB) or calcium channel blockers (CCB), but what is the role of magnesium sulfate (MgSO4) as an adjunct in the treatment of AF with RVR?
Paper: Bouida W, Beltaief K, Msolli MA, et al. Low-dose Magnesium Sulfate Versus High Dose in the Early Management of Rapid Atrial Fibrillation: Randomized Controlled Double-blind Study (LOMAGHI Study). Acad Emerg Med. 2019 Feb;26(2): 183-191
What: randomized, controlled, double-blind clinical trial evaluating high-dose IV magnesium (9g in 100cc NS, n=153) vs low-dose IV magnesium (4.5g in 100cc NS, n=148) vs placebo (100cc NS, n=149) in addition to routine AV nodal blocking agents in rapid AF.
Inclusion criteria: those > 18 years old in AF with RVR (>120 beats/min)
Exclusion criteria: SBP<90, AMS, renal failure (Cr ~2), acute MI, NYHA class 3-4 heart failure, contraindication to magnesium, rhythm other than atrial fibrillation or wide-complex rhythm
Primary outcome: therapeutic response = ventricular rate < 90 beats/minute or ≥ 20% reduction in VR within 4 hours
Secondary outcome: time from start of treatment to therapeutic response, rate of conversion to sinus rhythm, and adverse events requiring treatment discontinuation or caused death
Results: There was a statistically significant difference in therapeutic response rate and absolute difference in rate reduction between low-dose magnesium and placebo at 4h (64.2% vs. 43.6% p < 0.05; absolute difference = 20.5%, p < 0.05). The most common adverse event associated with magnesium was minor flushing and more common in the high-dose group.
Limitation: In this study, digoxin was the most commonly used rate control agent (47.5%) compared to BB (21.7%) or CCB (30.8%), differing from our usual practice. Exact dosing of each rate control agent was also not specified. However, obtained results were not significantly different in a secondary analysis including only those who received BB or CCB.
Implication: In patients presenting in AF with RVR, the addition of low-dose IV magnesium to standard rate-control agents acts synergistically and may be beneficial in achieving therapeutic response compared to rate control agents alone. Consider low-dose magnesium in your next patient in rapid AF, and as always tailor to the individual patient and discuss with colleagues and peers
Written by:
Carlos Mikell, M.D.
Cook County EM Residency | PGY3
@CarlosMikellMD
Garrett Prince, M.D.
Cook County EM Residency | PGY3
@GarrettPrince8
Peer Reviewed By:
Mark Mycyk, M.D.
Chair of Division of Research
Department of Emergency Medicine | Cook County Health