Second Leicester Magnesium Intervention Trial - LIMIT-2


IV magnesium on mortality in suspected acute MI.


To assess the effect of IV magnesium in suspected acute MI.

Study Design

Study Design:

Patients Screened: Not given
Patients Enrolled: 2,316
Mean Follow Up: 2.7 years
Mean Patient Age: 62
Female: 27

Patient Populations:

Suspected acute MI


Complete heart block
Renal failure

Primary Endpoints:

Mortality at 28 days

Secondary Endpoints:

Left ventricular failure while in coronary care unit

Drug/Procedures Used:

IV Magnesium sulfate or normal saline over 24 hours.

Concomitant Medications:

Aspirin, Thrombolytic therapy

Principal Findings:

Myocardial infarction was confirmed in 65% of each group, with closely similar rises in cardiac enzymes.

Mortality at 28 days, the primary trial endpoint, was reduced by 24% (95% CI, 1 to 43%, p=0.04) in the magnesium group. The occurrence of left ventricular failure while in the coronary care unit was reduced by 25% (7-39%, p=0.009).

In long-term follow-up (1-5.5 years, mean 2.7 years), magnesium therapy reduced the mortality rate from ischemic heart disease by 21% (p=0.001) and all-cause mortality by 16% (p=0.03).

There was no significant difference between the groups in the incidence of heart block or the use of antiarrhythmic drugs, direct-current cardioversion, or temporary pacing.


The LIMIT-2 data conflict with the negative results of ISIS-4, a study of 58,050 patients with suspected myocardial infarction. The difference between the two study results may be attributable to dosing regimens, to patient populations, or to play of chance. The benefit of magnesium for acute myocardial infarction is a subject of continued debate (Am J Cardiol 1995;76:172-3).


1. Lancet 1992; 339: 1553-8. Final results
2. Lancet 1994; 343:816-9. Long-term follow-up

Clinical Topics: Arrhythmias and Clinical EP, Implantable Devices, EP Basic Science

Keywords: Magnesium Sulfate, Myocardial Infarction, Follow-Up Studies, Coronary Care Units, Heart Block, Electric Countershock

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