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IV Magnesium use in the treatment of acute atrial fibrillation with rapid ventricular response in the Emergency Department including cardiovascular compromise

Three Part Question

In [adult ED patients in atrial fibrillation with rapid ventricular rate refractory to standard medications unable to tolerate standard medications] does the addition of [IV magnesium] lead to [decrease in ventricular rate].

Clinical Scenario

70 yo male presents to ED with SOB and hypotension 75/40 with HR of 160. Pt found to be in afib. Pt does have h/o afib but usually rate controlled with dig. Pt is unsure how long he has been in afib. Pt is given 10mg of dilt after 1L IV NS bolus and pressure drops to 70/35. No change in HR. Would the addition of IV magnesium help with rate control of this patient?

Search Strategy

Ovid PubMed OR magnesium OR MGSO4

Then excluded post-op CABG studies, theoretical, lab based, animal models
Included prospective, clinical comparison studies of mag vs. another agent or with another agent for management of atrial fibrillation

13 Studies Included in my review

Excluded post-op CABG studies, theoretical, lab based, animal models

Included prospective, clinical comparison studies of mag vs. another agent or with another agent for management of atrial fibrillation

Search Outcome

211 total search results, limited to 13 after reviewing for criteria described above

Relevant Paper(s)

Author, date and country Patient group Study type (level of evidence) Outcomes Key results Study Weaknesses
Gullestad et al.
ED pts with SVT with onset < 1w; N = 57 mag vs. verapamil; randomized, single-blind conversion to sinus rhythm58% of Mag group converted to sinus rhythm in 4h; 19% of Verapamil group converted; p < 0.01mag alone
Hays et al.
ED pts with new afib; N = 15 Mag + Digoxin after 30m clinical case seriesrate at 5m, then 30m for 3.5hVentricular Rate decrease of 16bpm +/- 7 and improved w/dig to 26% +/- 7no comparison group, small, case series
Joshi et al.
ED pts with SVT > 160bpm; N = 154 2g MgSO4 IV vs. 5mg Verapamil IV; randomized HR < 100 binarylower rate control with mag (19/74, 25.7%) compared to verapamil (48/80, 60%) p < 0.0001mag alone
ED pts with Afib HR > 120bpm N = 34 2g MgSO4 IV then 1g/h over 6h; clinical case series rate at 15, 30, 60m; mag levelStasticially significant decrease in VR at each time period; no correlation between mag level and responseno comparsion group, mag alone
Chiladakis et al.
ED pts with Afib HR > 120bpm; N = 46 mag vs. diltiazem; RCTrate at 1, 2, 3, 4, 5, 6h; conversion to sinus rhythm at 6hsimilar decrease in both groups at each hour; higher conversion to sinus rhythm in mag group at 6h (13/23, 57%, p = 0.03)not blinded, single agent tx
ED pts with new afib; N = 199 standard care + 2.5g Mag or standard + NS; randomized, double-blind, placebo controlled HR < 100, Mean HR reductionMag more likely to lead to HR < 100bpm (RR 1.89, 95%CI 1.38-2.59); standard tx most often wsa digno control of other agents given with mag
Ho et al.
new afib, pooled studies; N = 515 mag vs. placebo or mag vs. another agent; meta-analysis HR < 100, conversion to NSR, reduction of ventricular responsecompared to placebo, mag decreased ventricular response more when added to dig; less effective in reducing ventricular response compared to amio, mag was less likely to cause bradycardianot a study
Onalan et al.
new afib, pooled studies; N = 779 mag vs. placebo or mag vs. another agent; meta analysis HR < 100, conversion to NSR, reduction of ventricular responsemag was effective in achieving rate and rhythm control compared to placebo; shorter response time in mag group compared to placebonot a study
pts with afib who received ibutilide; N =229 mag w/ibutilide vs. mag without ibutilide consecutive enrollment conversion to NSRmag increased the odds of NSR conversion by 78%; OR 1.78, 95% CI 1.02-3.09
Kanji et al.
new afib, pooled studies; N = 143 mag vs. amio, procainamide, esmolol, verapamil, dilt; systematic review conversion to NSRno difference across groupsnot a study
ED pts with new afib HR > 100bpm; N = 48 mag vs. placebo; randomized HR q15m; conversion to NSRno difference across groupsmag alone, small sample


More randomized control trials are needed specifically comparing the ADDITION of magnesium to usual care. Furthermore, specific populations of patients need to be targeted - such as hypotensive patients who do not respond to electric cardioversion (or who are not optimal candidates for cardioversion) or who are refractory to tolerable doses of BP lowering anti-arrhythmics

Editor Comment


Clinical Bottom Line

The addition of magnesium (between 2g and 5g IV push) likely does not cause any harm to patients presenting in Acute Atrial Fibrillation with Rapid Ventricular Response to the Emergency Department. The addition of IV Magnesium may provide benefit in hypotensive patients not able to tolerate higher doses of BP lowering anti-arrhythmic agents. It is likely worth "trying" a dose of Mag in a refractory patient whom is not an ideal candidate for electric cardioversion


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  2. Hays JV, Gilman JK, Rubal BJ. Effect of magnesium sulfate on ventricular rate control in atrial fibrillation. Ann Emerg Med. 1994; 61-4.
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  5. Chiladakis JA, Stathopoulos C, Davlouros P, Manolis AS. Intravenous magnesium sulfate versus diltiazem in paroxysmal atrial fibrillation. Int J Cardiol. 2001; 287-91.
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