Controlled reperfusion after myocardial ischemia in a canine model monitored by two-dimensional phosphorus 31...

Phosphorus 31 magnetic resonance spectroscopy at 2 T was used to monitor high-energy phosphate metabolism over a 3-week period in a canine model of myocardial infarction and reperfusion. Twenty animals were divided into two groups: group 1 (n = 11) received intravenous nitroglycerin beginning at the onset of coronary occlusion; group 2 (n = 9) received a 105-minute infusion of superoxide dismutase (SOD) beginning at the onset of reperfusion. A metabolic protective effect was observed (vs controls) with both agents, manifested by a reduction in the degree of pH decline from baseline values and preservation of the adenosine triphosphate/total phosphate ratio during occlusion and reperfusion. Further, both treatments, compared with controls, produced a lower infarct/zone at risk ratio: controls, 1.5 +/- 1.2; nitroglycerin, 0.52 +/- 0.50; and SOD, 0.64 +/- 0.40. The technique of 31P magnetic resonance spectroscopy demonstrated its use for the noninvasive assessment of myocardial metabolism in response to therapeutic intervention.