Long-Term Outcome of Intravenous Magnesium Therapy in Thrombolysis-Ineligible Acute Myocardial Infarction Patients

Abstract

The aim of our study was to analyze the long-term survival and cardiac function in 194 consecutive, thrombolysis-ineligible acute myocardial infarction (AMI) patients receiving 48-hour intravenous magnesium sulfate (22 g) – 96 patients, compared with placebo – 98 patients. After a mean 4.8-year follow-up, all-cause mortality and cardiac mortality were significantly lower in the magnesium compared to the placebo group [(18 vs. 33 patients, p < 0.01) and (12 vs. 30 patients, p < 0.001), respectively]. Rest radionuclide ventriculography tests for left-ventricular ejection fraction (LVEF) were assessed in surviving patients up to completion of follow-up. Magnesium-treated patients had a significantly higher LVEF (0.51 ± 0.10 vs. 0.44 ± 0.14, p < 0.05) and a lower incidence of heart failure compared to placebo-treated patients (12 vs. 3 patients, p = 0.02). Beneficial effects of intravenous magnesium therapy in thrombolysis-ineligible AMI patients appeared to last for at least 4.8 years, concomitant with preserved LVEF, suggesting a favorable role for acute magnesium treatment in these patients.

Magnesium, Oxidative Stress, Inflammation, and Cardiovascular Disease

“…Low serum Mg is associated with increased risk and mortality of acute MI [ 191 , 214 ], and Mg deficiency, in turn, aggravates MI by inducing mitochondrial dysfunction and increasing oxidative stress-induced ischemic injury [ 96 , 110 , 215 , 216 ]. In Mg-treated patients, there is ~20% reduction in infarct size [ 217 ], ~24%–50% decreased mortality [ 20 , 48 , 192 , 214 , 218 , 219 ], decreased rates of arrhythmias after infarction [ 48 , 217 , 218 , 219 , 220 ], increased ejection fraction [ 221 ], and improved myocardial contractile function [ 193 ]. For example, in a meta-analysis with eight clinical trials, IV Mg treatment of 930 acute MI patients showed a 49% reduction in VT/VF, a 58% reduction of incidence of cardiac arrest, and a 54% reduction in mortality [ 48 ].…”

“…For instance, oral Mg L-lactate treatment of patients with ICDs who had Mg deficiency did not reduce the occurrence of arrhythmias in ICD patients and had little impact on the health-related quality of life [ 319 ]. While several studies show that IV Mg supplementation (MgSO 4 and MgCl 2 ) improved mortality in acute MI patients [ 192 , 218 , 219 , 221 ], Feldstedt et al observed no improvement with IV MgCl 2 on either the in-hospital or the follow-up mortality after acute myocardial infarction [ 320 ]. Moreover, Mg infusion was accompanied by a significantly increased incidence of atrioventricular conduction disturbances.…”

Is Hypothermia Useful in Managing Critically Ill Patients? Which Ones? Under What Conditions?

“…28,29 Magnesium supplementation may be especially important given its known protective role in neuronal and myocardial injury. 28,[30][31][32] Hypothermia-induced decreases in insulin sensitivity may lead to hyperglycemia. This could enhance susceptibility to infection and also might exacerbate secondary brain injury.…”