SHARE @ Advocate Health - Midwest - Scientific Day: ATRIUM: Atrial Tachycardia Reduction With Intravenous Use of Magnesium
 

Affiliations

Advocate Christ Medical Center, Advocate Lutheran General Hospital

Abstract

Background/Significance:

Magnesium sulfate is a safe and effective option for the management of atrial fibrillation and flutter with rapid ventricular response (AFF RVR). However, the optimal dose is unknown. There is significant heterogeneity in the studied doses, ranging from 1 g to 9 g, with higher doses associated with increased adverse effects such as flushing and hypotension.

Purpose:

The objective of this study is to compare the efficacy of lower doses of intravenous (IV) magnesium 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 magnesium sulfate 2 g vs 4 g vs placebo for patients presenting with AFF RVR. All study patients receive standard weight-based IV diltiazem after magnesium administration is complete. The primary endpoint is ventricular rate control within the first 2 hours of IV magnesium administration, defined as a ventricular rate less than 120 bpm. Secondary endpoints include the mean change in heart rate (HR) at pre-specified time points after the administration of magnesium and diltiazem, rate of conversion to normal sinus rhythm, and mean change in HR up to 24-hours after magnesium infusion. Descriptive statistics, t-test, 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. A power analysis indicated the need for 153 subjects, 51 in each group, to detect a difference of 40 bpm.

Results:

On interim analyses, a total of 15 patients (n=2, n=5, and n=8 in the placebo, magnesium 2 g, and magnesium 4 g arms, respectively) have been enrolled as of December 31, 2024. The percentage of patients who achieved rate control within 2 hours was 50% vs 60% vs 75% in the placebo, magnesium 2 g, and magnesium 4 g arms respectively (p=0.741). The mean reduction in HR at 2 hours after magnesium infusion was 26 bpm, 40 bpm, and 46 bpm in the placebo, magnesium 2 g, magnesium 4 g arms, respectively (p=0.434). There were no documented incidents of hypotension or bradycardia observed in any of the groups.

Conclusion:

Although not statistically significant, preliminary results indicate an improvement in rate control with magnesium compared to placebo for AFF RVR. 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 21, 2025; Park Ridge, IL.

Full Text of Presentation

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May 21st, 10:10 AM May 21st, 10:15 AM

ATRIUM: Atrial Tachycardia Reduction With Intravenous Use of Magnesium

Background/Significance:

Magnesium sulfate is a safe and effective option for the management of atrial fibrillation and flutter with rapid ventricular response (AFF RVR). However, the optimal dose is unknown. There is significant heterogeneity in the studied doses, ranging from 1 g to 9 g, with higher doses associated with increased adverse effects such as flushing and hypotension.

Purpose:

The objective of this study is to compare the efficacy of lower doses of intravenous (IV) magnesium 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 magnesium sulfate 2 g vs 4 g vs placebo for patients presenting with AFF RVR. All study patients receive standard weight-based IV diltiazem after magnesium administration is complete. The primary endpoint is ventricular rate control within the first 2 hours of IV magnesium administration, defined as a ventricular rate less than 120 bpm. Secondary endpoints include the mean change in heart rate (HR) at pre-specified time points after the administration of magnesium and diltiazem, rate of conversion to normal sinus rhythm, and mean change in HR up to 24-hours after magnesium infusion. Descriptive statistics, t-test, 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. A power analysis indicated the need for 153 subjects, 51 in each group, to detect a difference of 40 bpm.

Results:

On interim analyses, a total of 15 patients (n=2, n=5, and n=8 in the placebo, magnesium 2 g, and magnesium 4 g arms, respectively) have been enrolled as of December 31, 2024. The percentage of patients who achieved rate control within 2 hours was 50% vs 60% vs 75% in the placebo, magnesium 2 g, and magnesium 4 g arms respectively (p=0.741). The mean reduction in HR at 2 hours after magnesium infusion was 26 bpm, 40 bpm, and 46 bpm in the placebo, magnesium 2 g, magnesium 4 g arms, respectively (p=0.434). There were no documented incidents of hypotension or bradycardia observed in any of the groups.

Conclusion:

Although not statistically significant, preliminary results indicate an improvement in rate control with magnesium compared to placebo for AFF RVR. These findings need to be validated with the full sample size, which is anticipated to provide sufficient power to detect a significant difference.

 

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