A Phase 4 interventional study of Magnesium sulfate administration and Magnesium oxide in Critical Illness, sponsored by Scarborough General Hospital. Recruiting at 6 sites in Canada. Open to participants aged 16 Years and older. Per ClinicalTrials.gov, last updated 2026-09-24.
Sponsored by Scarborough General Hospital · Phase 4, Interventional, and Treatment
Among 318 studies in Atrial Fibrillation with a site in Canada — 50 open to participants now, 73 under way, 8 of them phase 3. Atrial Fibrillation · Canada.
Among the 318 studies in Atrial Fibrillation with a site in Canada, this one is the 20th largest by planned enrollment of the 261 interventional ones that give a count, is one of 10 that started in 2025, is one of 30 in phase 4, reaches primary completion later than 30 of the 72 other live ones, and was the 307th registered.
4,009 studies on the registry are indexed under Atrial Fibrillation; 961 are open to participants now.
Browse Atrial Fibrillation studies →50 of the 318 studies in Atrial Fibrillation with a site in Canada are open now. Recruiting first, the newest first:
Milestone Pharmaceuticals Inc. · Sites in Canada, United States, Netherlands
Ages 18+
Regeneron Pharmaceuticals · Sites in Canada, United States, Japan
Ages 18+
Pavel Antiperovitch · Sites in Canada
Ages 18+
French Cardiology Society · Sites in Canada, France, New Zealand
Ages 18+
Ottawa Hospital Research Institute · Sites in Canada
Ages 18+
A study can be open while its sites in Canada have not opened yet or have stopped. Only those recruiting at a site in Canada →
Of the 612 Atrial Fibrillation studies recruiting now, 407 (67%) set no upper age limit and 44 (7%) stop at 75 or younger; 21 take children under 18; 43 take healthy volunteers.
This study: 16 Years and older · all sexes · no healthy volunteers.
The full table on the hub →This tab as a report to print or save as PDF → With an account.
318 studies; the count open now beside each. This study's row is marked.
A study in two phases is counted once above. Listed by phase, each with its combined phases: Phase 1 4 · Phase 2 29 · Phase 3 64 · Phase 4 30
First in 1999; this study’s year is marked. 10 started in 2025.
By drug class, each counting the studies that test any of its medicines:
This study's planned enrollment of 3,853 is above the median of 150 across 2,476 interventional studies indexed under Atrial Fibrillation.
Median enrollment 282 across the 261 interventional studies, 297 across the 57 observational. Of the 217 that completed or were terminated, 80 (37%) have results posted.
This tab as a report to print or save as PDF → With an account.
128 of 318 have an industry lead sponsor. The 10 most frequent:
Scarborough General Hospital is the lead sponsor of 4 studies on the registry; 1 is open to participants now.
Scarborough General Hospital has 1 study filed under Atrial Fibrillation — fewer than ten, so there is no comparison to draw.
23 of the studies in Atrial Fibrillation with a site in Canada that are under way reach primary completion within a year, 1 of them phase 3. Phase 3 first, then by date:
| Study | Primary completion |
|---|---|
| NCT05757869Phase 3Janssen Research & Development, LLCA Study of Milvexian Versus Apixaban in Participants With Atrial Fibrillation | 2026-12-08 |
| NCT02150902Ottawa Heart Institute Research CorporationAugmented Wide Area Circumferential Catheter Ablation for Reduction of Atrial Fibrillation Recurrence | 2026-11-27 |
| NCT07245147Jacqueline JozaREDO-AF: Randomized Evaluation of Dual Options for AF Re-intervention | 2026-12 |
| NCT06249269Ratika ParkashReversal of Atrial Substrate to Prevent Atrial Fibrillation Cohort Study | 2026-12 |
| NCT05600829University of CalgaryA Behavioural Weight Loss Intervention Delivered in Cardiac Rehabilitation for Patients With Atrial Fibrillation and Obesity | 2026-12-30 |
Add all 23 to your calendar (.ics) → With an account.
Among the 318 studies in Atrial Fibrillation with a site in Canada, from their registry updates:
This tab as a report to print or save as PDF → With an account.
In patients with critical illness, such as severe infections, heart attacks, or respiratory failure, most intensive care units (ICUs) measure magnesium levels and give supplemental doses of magnesium when levels are below certain targets. However, the best targets are unknown. The goal of this clinical trial is to study protocols for magnesium supplementation in people with critical illness, comparing a protocol with higher target level to a protocol with a lower target level.
The main question this study aims to answer is whether magnesium supplementation protocols targeting a higher or lower level lead to better 30-day survival and less atrial fibrillation.
Participants will not have to do any specific tasks, undergo any additional tests, or complete any surveys.
Background: Measurement of serum magnesium levels, and administration of supplemental magnesium when levels are below target, is a common element of routine care for critically ill patients. However, targets for replacement vary, and the targets that lead to the best outcomes are unknown.
Methods: Multi-center open-label parallel group randomized controlled superiority trial of adult critically ill patients receiving protocolized magnesium replacement, comparing a higher target (>0.95mmol/L) to a lower target (>0.7mmol/L). The trial will be embedded into the electronic medical record (EMR) at 5 hospitals across 2 health networks in Ontario, Canada, with a shared EMR. Patients aged 16 years or older who have ICU admission orders and an order for the magnesium replacement protocol will be included. Patients with pre-eclampsia, sustained ventricular tachycardia, or neuromuscular junction disease will be excluded. The primary outcome will be an ordinal composite, evaluated at 30 days, composed of death and the number of days free of atrial fibrillation or flutter in ICU. Secondary outcomes will include ventricular arrhythmia and antiarrhythmics administered; receipt of vasopressors, ventilation, and new renal replacement therapy in ICU; lengths of ICU and hospital stay; hospital mortality at 60 and 90 days, magnesium levels, and magnesium supplementation. Analyses will use Bayesian regression with weakly skeptical priors and an intention-to-treat approach. Because both targets lie within the standard of care, the trial will use opt-out consent. Screening will be integrated with the EMR, such that when a patient meets inclusion criteria, a pop-up will appear for the ordering clinician. After the clinician confirms eligibility, the patient will be randomized and assigned to their target. Outcome ascertainment will occur within the EMR.
Discussion: This randomized controlled trial addresses an important uncertainty regarding routine care in the ICU with an EMR-embedded design. The innovative EMR-embedded design facilitates the large sample sizes and comprehensive, equitable recruitment needed for a trial evaluating a routine care intervention, and will lead to seamless integration with routine care upon trial completion.
4,009 studies on the registry are indexed under Atrial Fibrillation; 961 are open to participants now.
This study's planned enrollment of 3,853 is above the median of 150 across 2,476 interventional studies indexed under Atrial Fibrillation.
Browse Atrial Fibrillation studies →Scarborough General Hospital is the lead sponsor of 4 studies on the registry; 1 is open to participants now.
Compared within Atrial Fibrillation, this study's primary condition as ClinicalTrials.gg classifies it; the registry's first condition term is Critical Illness. The counts are of registry records indexed under each term, refreshed daily. How we classify →
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
Protocolized magnesium replacement according to magnesium level as follows: for 0.45 - 0.70mmol/L, magnesium sulfate 4g IV x 1 and repeat magnesium level the next day; for \< 0.45mmol/L, magnesium sulfate 6g IV x 1, alert most responsible physician, and repeat level in 4 hours.
Drug: Magnesium sulfate administration
Protocolized magnesium replacement according to magnesium level as follows: for 0.75-0.95mmol/L, magnesium sulfate 2g IV x 1, magnesium oxide 420 mg po q12h x 2, or magnesium glucoheptonate 30mL po q12h x 2; for 0.45 - 0.74mmol/L, magnesium sulfate 4g IV x 1 and repeat magnesium level the next day; for \< 0.45mmol/L, magnesium sulfate 6g IV x 1, alert most responsible physician, and repeat level in 4 hours.
Drug: Magnesium sulfate administration · Drug: Magnesium oxide · Drug: Magnesium glucoheptonate
Magnesium sulfate is used in both arms for magnesium replacement.
In the higher-target arm, magnesium oxide 420mg po q12h x 2 is one of the options available for magnesium replacement when magnesium levels lie between 0.75 and 0.95mmol/L.
Magnesium glucoheptonate 30mL po q12h x 2 is an oral option for magnesium replacement in the higher-target arm.
30-day ordinal composite of hospital mortality and days free of atrial fibrillation in ICU
This is an ordinal outcome with 32 levels ranging from -1 (worst) to 30 (best). It is evaluated at 30 days. The worst outcome (-1) corresponds to mortality in hospital within 30 days from trial enrollment. Among patients who do not die in hospital by day 30, we count the number of days when they did not have atrial fibrillation in the ICU. For example, a survivor who never had atrial fibrillation in ICU would be scored as "30." A survivor who had 5 days of atrial fibrillation in ICU would be scored as "25." A patient who is discharged from hospital, either to home or transferred to another site, but is readmitted to a study hospital and dies within 30 days of enrollment, would be counted as having had hospital mortality. This stipulation is relevant because of the frequency of transfers between sites within a health network, due to regionalization of services such as vascular surgery, thoracic surgery, dialysis, and angiography.
Time frame: 30 days after enrollment.
Organ-support free days
Number of days alive and free of invasive ventilation, vasopressors, and renal replacement therapy
Time frame: 30 days
ICU-free days
Number of days alive and not in ICU
Time frame: 30 days
Invasive ventilation-free days
Number of days alive and free of invasive ventilation
Time frame: 30 days
Vasopressor-free days
Days alive and not receiving vasopressors
Time frame: 30 days
Renal replacement therapy-free days
Days alive and not receiving renal replacement therapy in the ICU
Time frame: 30 days
Ventricular arrhythmia
Binary outcome noting the occurence of either sustained ventricular tachycardia or ventricular fibrillation in ICU (1), or not (0).
Time frame: 30 days
Intravenous antiarrhythmics
Binary variable noting administration of intravenous antiarrhythmics in ICU (1) or not (0). Intravenous antiarrhythmics include amiodarone, metoprolol, esmolol, diltiazem, procainamide, lidocaine, flecainide, adenosine, digoxin.
Time frame: 30 days
Magnesium and potassium levels in ICU
Daily levels of magnesium and potassium in ICU
Time frame: 30 days
Magnesium administrations
Magnesium administrations while in ICU (number per day)
Time frame: 30 days
Fluid balance
Daily fluid balance (sum of all liquid intakes minus the sum of all liquid outputs).
Time frame: 30 days
DOOR 1: Death and arrhythmia
This is a desirability of outcome ordinal ranking (DOOR) outcome. The possible binary levels are, from worst to best: death, ventricular arrhythmia, atrial fibrillation or flutter, none of the above.
Time frame: 30 days
DOOR 2: Survival, organ dysfunction, hospitalization, discharge
This is a desirability of outcome ordinal ranking (DOOR) outcome. The binary levels are, ordered from best to worst: discharge home, discharge to location other than home, ongoing hospital admission, persistent organ dysfunction in ICU, death.
Time frame: 30 days
Hospital mortality
Hospital mortality
Time frame: 60 days
Hospital mortality
Hospital mortality
Time frame: 90 days
Hospital length of stay
Length of hospitalization, including transfers within the health network.
Time frame: 90 days
Discharge destination
Categorical variable noting discharge destination on index hospitalization (eg home, retirement home, long-term care, acute care hospital, etc).
Time frame: 90 days
Magnesium administrations - by mass
Elemental magnesium administered (g per day)
Time frame: 30 days
Magnesium administrations - route
Route of magnesium administrations each day (PO vs IV)
Time frame: 30 days
Plan to share: Yes — Deidentified data will be posted in the Health Data Nexus (https://healthdatanexus.ai/) deidentified data repository overseen by the University of Toronto Temerty Centre for Artificial Intelligence Research and Education in Medicine. This will allow credentialed access to deidentified individual patient data.
Supporting information: Study protocol
Time frame: Deidentified data will be posted in the Health Data Nexus repository after publication of the primary trial results.
Access criteria: Credentialed access to the Health Data Nexus is available to anyone who fulfills the requirements, including an ethics course (TCPS2 2022) and signing a data use agreement.
Data sharing details ↗ · healthdatanexus.ai
Started Nov 2025 (actual). Primary completion is estimated for Mar 2027, 15 months after the start.
Of 129 non-industry phase 4 interventional studies under Atrial Fibrillation, half reached primary completion within 53 months of starting (the median), counting those still running; a quarter within 28 and three quarters within 81. This study's planned 15 months is below that.
Counting every sponsor, half of 141 studies reached it within 48 months; a quarter within 27 and three quarters within 81.
How these figures are worked out, and which studies are left out of them.
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Studies of the drug tested here: Magnesium Oxide
Scarborough General Hospital