Debate continues about whether intravenous magnesium sulfate improves outcomes in AMI. A study in Cardiovascular Drugs and Therapy evaluated how timing of magnesium administration relates to short- and long-term mortality in the contemporary percutaneous coronary intervention (PCI) era.

The retrospective observational cohort included 4,610 patients with acute type 1 myocardial infarction identified from the MIMIC-IV database. Patients were grouped by the interval between diagnosis and magnesium initiation: Q1 (no magnesium), Q2 (≤2 hours), Q3 (2–6 hours), Q4 (6–12 hours), and Q5 (≥12 hours). The primary outcome was 28-day all-cause mortality, and the secondary outcome was one-year all-cause mortality. Overall 28-day mortality was 18.5%.

Adjusted Kaplan-Meier analyses showed an association between intravenous magnesium sulfate and lower long-term mortality across all timing groups. Landmark analysis demonstrated a stronger association before 28 days (p<0.001). Restricted mean survival time analyses supported the consistency of these results.

Although the findings suggest a possible survival advantage, the single-center observational design cannot confirm causality. Well-designed randomized controlled trials are needed to determine whether intravenous magnesium sulfate improves outcomes in patients with AMI.