MAGNAM Trial, Magnesium Versus Amiodarone in Atrial Fibrillation in Critical Care

We will test MgSO4 and then digoxin IV (in 3 divided dose) as second line therapy with amiodarone IV as third line. Digoxin will be protocolised to commence between 30 minutes and 12 hours after MgSO4 if fast Atrial Fibrillation persists as initially designated (dose 1). Undiluted IV digoxin (12 mcg/kg) will be administered in 3 divided doses (6, 3 and 3 mcg/kg) separated by approximately 6 hrs (i.e. dose 1 at 30 mins - 12 hours after MgSO4, followed by dose 2 at -6 hrs and dose 3 at the approximately 12 hrs). Patients with renal dysfunction (creatinine clearance \<60 ml/min measured by the Modification of diet in renal disease formula) will receive a reduced dose of 8 mcg/kg in 3 divided doses (4, 2, and 2 mcg/kg) separated by the same time intervals. In the trial intervention group, amiodarone will be given approximately 120 mins after digoxin if necessary whilst completing the digoxin dose. Amiodarone as a 150 mg infusion over 10 minutes followed by 900 mg over 24 hours.

We will test Amiodarone (150mg IV then 900mg IV over the next 24 hours ) as first line treatment in the standard of care group. No more than 2g MgSO4 be delivered over 2 hours maximum for this group in the first 24 hours after randomisation unless clinically indicated for measured hypomagnesaemia (a value below the index hospital laboratories lower limit of normal).