Do coronary sinus magnesium levels really change in coronary surgery patients perioperatively

The role of the divalent cation magnesium in cardiovascular function has been receiving increasing attention. Hypomagnesemia is often reported to occur preoperatively and following cardiac surgery. Hypomagnesemia was also shown to be associated with cardiac arrhythmias and sudden cardiac death from ischemic heart disease. As a result of the described antiarrhythmic effects, intravenous magnesium supplementation has been recommended during myocardial infarction as well as after coronary artery bypass graft operations. The aim of this study was to determine the status and the changes of magnesium levels in a representative random test of elective coronary patients. Arterial, central venous and coronary sinus blood magnesium levels were taken before, during and after coronary bypass graft operations using cardiopulmonary bypass (CPB). As a control to the general shifts of electrolytes also the sodium, potassium and phosphate values are shown. The "common occurence" of pre-, intra- and postoperative hypomagnesemia in coronary bypass patients could not be confirmed in our patients. On the contrary it was found a significant increase (p < 0.05) of magnesium levels after going on cardiopulmonary bypass. Magnesium levels never fell below normal magnesium range (0.7 - 1.1 mmol / 1) perioperatively. The trends in all three compartments were comparable.