Effects of calcium on left ventricular function early after cardiopulmonary bypass

Evaluation of the effects of intravenous CaC1₂on systolic and diastolic function early after separation from cardiopulmonary bypass (CPB) Prospective study University hospital Twenty patients scheduled for elective coronary artery surgery Left ventricular (LV) pressures were measured with fluid-filled catheters. Data were digitally recorded during pressure elevation induced by tilt-up of the legs. Transgastric short-axis echocardiographic views of the LV were simultaneously recorded on videotape. Measurements were obtained before the start of CPB, 10 minutes after termination of CPB, after intravenous administration of CaC1₂, 5 mg/kg, and 10 minutes later.

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Systolic function was evaluated with the slope (Ees, mmHg/mL) of the systolic pressure-volume relation. Diastolic function was evaluated with the chamber stiffness constant (Kc, mmHg/mL) of the diastolic pressure-volume relation. CaC1₂increased Ees from 2.62 ± 0.46 to 5.58 ± 0.61 (mean ± SD), but induced diastolic dysfunction with an increase in Kc from 0.011 ± 0.006 to 0.019 ± 0.007. These changes were transient and had disappeared within 10 minutes after administration of CaC1₂. CaC1₂early after CPB transiently improved systolic function at the expense of an increase in ventricular stiffness, suggesting temporary diastolic dysfunction.