A double-blind, multi-centre, randomized, placebo-controlled, feasibility pilot trial in the prevention of new onset atrial fibrillation of critically ill patients admitted to an ICU.

Most studies of new onset atrial fibrillation (NOAF) in critical illness focus on treatment of this arrhythmia but this innovative study will focus on prevention. Parenteral Mg is a low cost and readily available treatment that may be beneficial for reducing the incidence of NOAF in critically ill patients, with the potential to improve patient centred outcomes and provide a cost effective prophylaxis. The main outcome of this study is to determine if it is feasible to conduct a randomized controlled trial comparing parenteral magnesium sulfate with placebo for the prophylaxis of new onset atrial fibrillation in critically ill patients.

Inclusion Criteria

1. Age ≥18 years;

2. Admitted to an ICU with one or more of the following:

   1. Non-invasive ventilation (including CPAP, Bipap and high flow oxygen (>10L/min) or invasive mechanical ventilation with an expected duration >24 hours for respiratory failure (hypercarbic or hypoxic)
   2. Vasopressor or inotropic support with an expected duration of >24 hours
   3. Cardiac arrest

3. Continuous cardiac monitoring.

Exclusion Criteria

1. Receiving ICU intervention (Non-invasive ventilation (including high flow nasal canula), invasive mechanical ventilation or inotropic support) for >18 hours
2. Receiving IMV for airway protection only (for example, isolated head trauma)
3. Active atrial fibrillation at the time of enrolment
4. On oral or continuous infusion of Amiodarone
5. Unlikely to survive >24 hours or palliative patients
6. Cardiac surgery patients
7. Patients requiring parenteral magnesium therapy (e.g. pre-eclampsia, asthma)
8. Patients receiving dialysis
9. Positive pregnancy test (females <50 years old)
10. Previously enrolled in this trial
11. Treating physician refuses enrollment