Recommended Citation
McKillip R, Ashrafi S, Hussein H, et al. Atrial Tachycardia Reduction with Intravenous Use of Magnesium (ATRIUM). Presented at Scientific Day; May 20, 2026; Milwaukee, WI.
Abstract
Background/Significance:
Magnesium sulfate (Mg) is a safe and effective option for the management of atrial fibrillation or atrial flutter with rapid ventricular response (AFF RVR); however, the optimal dose is unknown. Prior research on its effectiveness has primarily used high-dose regimens (4-9g), which are associated with increased adverse effects, such as hypotension and bradycardia. Whether lower doses can provide comparable rate-control benefit while reducing adverse events is unknown.
Purpose:
The objective of this study is to compare the efficacy of lower doses of intravenous (IV) Mg to successfully decrease the ventricular rate to under 120 beats per minute (bpm) in the management of AFF RVR for patients receiving IV diltiazem.
Methods:
This is a prospective, double-blind, randomized controlled trial comparing Mg sulfate 2 g vs. 4 g vs. placebo for patients presenting with AFF RVR. All study patients receive standard weight based IV diltiazem after study drug administration is complete. The primary endpoint is rate control within the first 2 hours of IV Mg administration, defined as a ventricular rate of less than 120 bpm. Secondary endpoints include the mean change in heart rate (HR) at pre-specified time points after the administration of Mg and diltiazem and mean change in HR up to 24-hours after Mg infusion. Descriptive statistics, tests, chi-squared, and ANOVA tests were used for data analysis. All tests were two-tailed and p values of 0.05 were considered statistically significant. Power analysis indicated the need for 153 subjects, 51 in each group, to detect a difference of 40 bpm.
Results:
A total of 78 patients (n=24, n=26, and n=28 in the placebo, Mg 2 g, and Mg 4 g arms, respectively) were enrolled as of October 31, 2025. The percentage of patients who achieved rate control within 2 hours was 75% vs. 73% vs. 64% in the placebo, Mg 2 g, and Mg 4 g arms respectively (p=0.65). The mean reduction in HR at 15 minutes after Mg infusion was 1 bpm, 26 bpm, and 20 bpm in the placebo, Mg 2 g, Mg 4 g arms, respectively (p=0.008). There were no documented incidences of hypotension or bradycardia observed.
Conclusion:
Magnesium appears to demonstrate a statistically significant reduction in HR at 15 minutes compared 19 to placebo, without observed hypotension or bradycardia. These findings need to be validated with the full sample size, which is anticipated to provide sufficient power to detect a significant difference.
Presentation Notes
Presented at Scientific Day; May 20, 2026; Milwaukee, WI.
Full Text of Presentation
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Document Type
Oral/Podium Presentation
Atrial Tachycardia Reduction with Intravenous Use of Magnesium (ATRIUM)
Background/Significance:
Magnesium sulfate (Mg) is a safe and effective option for the management of atrial fibrillation or atrial flutter with rapid ventricular response (AFF RVR); however, the optimal dose is unknown. Prior research on its effectiveness has primarily used high-dose regimens (4-9g), which are associated with increased adverse effects, such as hypotension and bradycardia. Whether lower doses can provide comparable rate-control benefit while reducing adverse events is unknown.
Purpose:
The objective of this study is to compare the efficacy of lower doses of intravenous (IV) Mg to successfully decrease the ventricular rate to under 120 beats per minute (bpm) in the management of AFF RVR for patients receiving IV diltiazem.
Methods:
This is a prospective, double-blind, randomized controlled trial comparing Mg sulfate 2 g vs. 4 g vs. placebo for patients presenting with AFF RVR. All study patients receive standard weight based IV diltiazem after study drug administration is complete. The primary endpoint is rate control within the first 2 hours of IV Mg administration, defined as a ventricular rate of less than 120 bpm. Secondary endpoints include the mean change in heart rate (HR) at pre-specified time points after the administration of Mg and diltiazem and mean change in HR up to 24-hours after Mg infusion. Descriptive statistics, tests, chi-squared, and ANOVA tests were used for data analysis. All tests were two-tailed and p values of 0.05 were considered statistically significant. Power analysis indicated the need for 153 subjects, 51 in each group, to detect a difference of 40 bpm.
Results:
A total of 78 patients (n=24, n=26, and n=28 in the placebo, Mg 2 g, and Mg 4 g arms, respectively) were enrolled as of October 31, 2025. The percentage of patients who achieved rate control within 2 hours was 75% vs. 73% vs. 64% in the placebo, Mg 2 g, and Mg 4 g arms respectively (p=0.65). The mean reduction in HR at 15 minutes after Mg infusion was 1 bpm, 26 bpm, and 20 bpm in the placebo, Mg 2 g, Mg 4 g arms, respectively (p=0.008). There were no documented incidences of hypotension or bradycardia observed.
Conclusion:
Magnesium appears to demonstrate a statistically significant reduction in HR at 15 minutes compared 19 to placebo, without observed hypotension or bradycardia. These findings need to be validated with the full sample size, which is anticipated to provide sufficient power to detect a significant difference.
Affiliations
Advocate Christ Medical Center, Advocate Good Shepherd Hospital, Advocate Lutheran General Hospital