[Abnormal electrocardiographic changes induced by hypocalcemia secondary to extracorporeal circulation]

We report hereby the case of a 20-year-old woman, whose electrocardiogram showed unusual repolarization abnormalities 36 hours after open heart surgery. They were due to pure hypocalcemia (7,1 mg/100 ml) secondary to extracorporeal circulation, were sudden in onset, transient, variable within a few minutes, and immediately suppressed by intravenous calcium chloride. Some of the changes were similar to those already reported in literature (lengthening of QT and ST segments, changes in T wave voltage but not duration) whereas other were quite unusual i.e. the extreme variability and transientness of these changes, the marked ST level alterations and the presence of wide and diphasic U waves. Intravenous administration of 2 g of calcium chloride was followed by immediate and complete normalization of the electrocardiographic tracing.