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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

magnesium.mp OR magnesium sulphate.mp OR MGSO4
AND
atrial fibrillation.mp


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. 1993 USA	ED pts with SVT with onset < 1w; N = 57	mag vs. verapamil; randomized, single-blind	conversion to sinus rhythm	58% of Mag group converted to sinus rhythm in 4h; 19% of Verapamil group converted; p < 0.01	mag alone
Hays et al. 1994 USA	ED pts with new afib; N = 15	Mag + Digoxin after 30m clinical case series	rate at 5m, then 30m for 3.5h	Ventricular Rate decrease of 16bpm +/- 7 and improved w/dig to 26% +/- 7	no comparison group, small, case series
Joshi et al. 1995 India	ED pts with SVT > 160bpm; N = 154	2g MgSO4 IV vs. 5mg Verapamil IV; randomized	HR < 100 binary	lower rate control with mag (19/74, 25.7%) compared to verapamil (48/80, 60%) p < 0.0001	mag alone
Eray 2000	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 level	Stasticially significant decrease in VR at each time period; no correlation between mag level and response	no comparsion group, mag alone
Chiladakis et al. 2001 Greece	ED pts with Afib HR > 120bpm; N = 46	mag vs. diltiazem; RCT	rate at 1, 2, 3, 4, 5, 6h; conversion to sinus rhythm at 6h	similar 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
Davey 2005 USA	ED pts with new afib; N = 199	standard care + 2.5g Mag or standard + NS; randomized, double-blind, placebo controlled	HR < 100, Mean HR reduction	Mag more likely to lead to HR < 100bpm (RR 1.89, 95%CI 1.38-2.59); standard tx most often wsa dig	no control of other agents given with mag
Ho et al. 2007 Australia	new afib, pooled studies; N = 515	mag vs. placebo or mag vs. another agent; meta-analysis	HR < 100, conversion to NSR, reduction of ventricular response	compared 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 bradycardia	not a study
Onalan et al. 2007 Canada	new afib, pooled studies; N = 779	mag vs. placebo or mag vs. another agent; meta analysis	HR < 100, conversion to NSR, reduction of ventricular response	mag was effective in achieving rate and rhythm control compared to placebo; shorter response time in mag group compared to placebo	not a study
Tercius 2007	pts with afib who received ibutilide; N =229	mag w/ibutilide vs. mag without ibutilide consecutive enrollment	conversion to NSR	mag increased the odds of NSR conversion by 78%; OR 1.78, 95% CI 1.02-3.09
Kanji et al. 2008	new afib, pooled studies; N = 143	mag vs. amio, procainamide, esmolol, verapamil, dilt; systematic review	conversion to NSR	no difference across groups	not a study
Chu 2009	ED pts with new afib HR > 100bpm; N = 48	mag vs. placebo; randomized	HR q15m; conversion to NSR	no difference across groups	mag alone, small sample

Comment(s)

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

KMJ

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

References

1. Gullestad L, Birkeland K, Mølstad P, Høyer MM, Vanberg P, Kjekshus J. The effect of magnesium versus verapamil on supraventricular arrhythmias. Clinical Cardiology 1993; 429-34.
2. Hays JV, Gilman JK, Rubal BJ. Effect of magnesium sulfate on ventricular rate control in atrial fibrillation. Ann Emerg Med. 1994; 61-4.
3. Joshi PP, Deshmukh PK, Salkar RG. Efficacy of intravenous magnesium sulphate in supraventricular tachyarrhythmias. J Assoc Physicians India 1995; 529-31.
4. Eray O, Akça S, Pekdemir M, Eray E, Cete Y, Oktay C. Magnesium efficacy in magnesium deficient and nondeficient patients with rapid ventricular response atrial fibrillation. Eur J Emerg Med. 2000; 287-90.
5. Chiladakis JA, Stathopoulos C, Davlouros P, Manolis AS. Intravenous magnesium sulfate versus diltiazem in paroxysmal atrial fibrillation. Int J Cardiol. 2001; 287-91.
6. Davey MJ, Teubner D. A randomized controlled trial of magnesium sulfate, in addition to usual care, for rate control in atrial fibrillation. Ann Emerg Med 2005; 347-53.
7. Ho KM, Sheridan DJ, Paterson T. Use of intravenous magnesium to treat acute onset atrial fibrillation: a meta-analysis. Heart 2007;433-40
8. Onalan O, Crystal E, Daoulah A, Lau C, Crystal A, Lashevsky I. Meta-analysis of magnesium therapy for the acute management of rapid atrial fibrillation. Am J Cardiol 2007;1726-32.
9. Tercius AJ, Kluger J, Coleman CI, White CM. Intravenous magnesium sulfate enhances the ability of intravenous ibutilide to successfully convert atrial fibrillation or flutter. Pacing Clin Electrophysiol. 2007; 1331-5.
10. Kanji S, Stewart R, Fergusson DA, McIntyre L, Turgeon AF, Hébert PC. Treatment of new-onset atrial fibrillation in noncardiac intensive care unit patients: a systematic review of randomized controlled trials. Crit Care Med 2008; 1620-4.
11. Chu K, Evans R, Emerson G, Greenslade J, Brown A. Magnesium sulfate versus placebo for paroxysmal atrial fibrillation: a randomized clinical trial. Acad Emerg Med. 2009; 295-300