Effects of Gadolinium on Regionally Stunned Myocardium: Temporal Considerations

ObjectivesThe lanthanide cation, gadolinium (Gd3+), accelerates recovery of stunned myocardium when given prior to ischemia. This study sought to determine whether giving Gd3+ during ischemia or during reperfusion also ameliorates stunning, as these temporal relationships could help determine the clinical utility of this novel agent.MethodsRegional myocardial stunning was induced in anesthetized dogs by coronary occlusion for 15 min followed by reperfusion for 3 h. Gd3+ (500 μmol) was given intravenously in three treatment groups: [1] preischemia; [2] during ischemia; [3] after reperfusion. No Gd3+ was given to controls (Group 4). Measures of global and regional myocardial function were assessed serially.ResultsTreatment with Gd3+ prior to ischemia (Group 1) had no effects on hemodynamics or regional contraction. Coronary occlusion resulted in diastolic lengthening and paradoxical systolic bulging equally in all groups. After 3 h of reperfusion, regional systolic shortening (%) in the stunned segment was greater in Groups 1 (10.9 ± 3.4; P = 0.02) and 2 (6.6 ± 1.3; P = 0.047) compared with controls (−0.6 ± 0.03). Recovery of systolic function (% of baseline shortening) after 3 h of reperfusion was similarly improved in Groups 1 (56.1 ± 16.8; P = 0.02) and 2 (43.3 ± 8.1; P = 0.04) compared with controls (−11.5 ± 4.7).ConclusionsGadolinium has no inherent inotropic effects but enhances recovery of stunned myocardium. This effect appears maximal if Gd3+ is given prior to ischemia, indicating potential utility in elective cardiac surgical procedures or percutaneous coronary interventions. Gadolinium also enhances recovery if given during ischemia but prior to reperfusion, and may thus be useful in acute coronary syndromes as well.