['The calcium-channel blocking effect of magnesium might have protective effects in patients undergoing cardiopulmonary bypass surgery. We assessed the effects of magnesium on hearts undergoing coronary artery bypass surgery with intermittent warm blood hyperkalemic cardioplegia in the antegrade fashion.', 'Twenty patients undergoing coronary bypass surgery were randomly divided into two groups, a control group who received intermittent antegrade warm blood hyperkalemic cardioplegia for myocardial protection, and a study group who received the same solution with the addition of magnesium to the cardioplegia. Extracellular substrates (creatinine phosphokinase, creatinine phosphokinase-MB group, lactate dehydrogenase, c-reactive protein, and cardiac troponin I were measured preoperatively and postoperatively.', 'There were significant differences in the post-operative concentrations of creatinine phosphokinase, creatinine phosphokinase-MB group, c-reactive protein, and lactate dehydrogenase after cardiopulmonary bypass (P<0.001) in the study group compared with the control subjects. Cardiac troponin I levels were also significantly lower in the study group after cardiopulmonary bypass (P<0.005).'] Does magnesium decrease cardiac injury in patients undergoing coronary artery bypass surgery?