Comparing Magnesium 2g Versus 4g Versus Placebo in the Incidence of Treating AFF RVR

Intravenous magnesium has become a commonly utilized agent in the treatment of cardiac arrhythmias as an adjunct therapy to rate and rhythm control medications, such as its use in atrial fibrillation or atrial flutter with rapid ventricular response (AFF RVR). Though its benefit in the treatment of AFF RVR has been well documented, a consensus on the optimal dosing of magnesium has yet to be achieved. Only one randomized, controlled, double-blinded study has investigated the optimal dosing of magnesium.

Primary Outcome Measures

1. Ventricular rate control
   Assessing ventricular rate control within the first 2 hours of intravenous magnesium administration as defined as a ventricular rate of \< 120 bpm.

Secondary Outcome Measures

1. Time to achieve goal HR (heart rate)
   Mean change in heart rate and rhythm after the administration of magnesium sulfate as well as after the administration of diltiazem
2. Rate of conversion
   Rate of conversion to normal sinus rhythm (NSR)
3. Incidence of hypotension
   SBP \< 90 mmHg or MAP (mean arterial pressure) \< 65
4. Change in heart rate
   Mean change in heart rate up to 24 hours after magnesium infusion
5. Clinical need for rescue medication administration
   Dose and route of rescue medications given (magnesium and diltiazem)
6. Adverse effects
   Patient reported adverse effects (e.g.. flushing, headache, nausea, new onset or worsening lightheadedness since beginning the magnesium infusion)