Effects of magnesium supplementation in a porcine model of myocardial ischemia and reperfusion.
We tested the hypothesis that acute, intravenous (i.v.) magnesium (Mg2+) supplementation would protect against myocardial stunning in an in situ swine model of regional ischemia and reperfusion and that a concomitant inhibitory effect on platelet aggregation would be elicited. An open-chest model was used, with transient occlusion of the left anterior descending coronary artery (LAD) for 8 min. Regional contractile function was assessed by measuring wall thickening fraction with epicardial Doppler crystals. One control group (n = 6) and two treatment groups were studied: group I (n = 6) received 750 mg MgSO4 before occlusion; group II (n = 6) received 1 g MgSO4 after the occlusion. Both protocols produced significant hypermagnesemia. In group I, platelet aggregation was measured before and after Mg2+ treatment using platelet-rich plasma (PRP) and various agonists (ADP 5 and 10 mM and collagen 1 mg/ml). As compared with controls, both treatment groups experienced significantly less postischemic dysfunction, with systolic function returning more quickly to baseline. Furthermore, platelet aggregation was significantly decreased immediately after Mg2+ infusion. Inhibition of platelet aggregation induced by Mg2+ treatment occurs concomitantly with significant amelioration of postischemic myocardial dysfunction.
Atar
D
D
Department of Medicine, University of Maryland Medical Center, Baltimore 21201.
Serebruany
V
V
Poulton
J
J
Godard
J
J
Schneider
A
A
Herzog
W R
WR
D000818:Animals; D005260:Female; D006439:Hemodynamics / Q000187:drug effects; D007262:Infusions, Intravenous; D008274:Magnesium / Q000097:blood / Q000627:therapeutic use*; D008955:Models, Cardiovascular; D009200:Myocardial Contraction / Q000187:drug effects; D017202:Myocardial Ischemia / Q000517:prevention & control*; D015425:Myocardial Reperfusion; D017682:Myocardial Stunning / Q000517:prevention & control*; D010974:Platelet Aggregation / Q000187:drug effects; D013552:Swine
D008274:Magnesium