Effect of Esmolol Given During Cardiopulmonary Bypass on Fractional Area of Contraction from Transesophageal Echocardiography

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The infusion of esmolol during hypothermic cardiopulmonary bypass (CPB) has no negative myocardial effects after CPB, despite increased esmolol levels during CPB due to hypothermia. The purpose of this randomized, double-blind, prospective study was to measure the effects of esmolol infused during CPB on cardiac function as measured by calculated indices of cardiac work and by transesophageal echocardiography (TEE). Patients scheduled for CPB were randomized to receive intravenous esmolol (300 micrograms.kg-1.min-1 during CPB after bolus of 2 mg/kg prior to CPB) or placebo. Infusion was stopped at 10 min after release of aortic cross-clamp. Hemodynamics and TEE were recorded during the procedure. Fractional area of contraction (FAC), an approximation of left ventricular ejection fraction, was calculated from end-diastolic and end-systolic areas. Esmolol was administered to 15 patients and placebo to 14. Heart rates in the esmolol group were lower during infusion and prior to CPB (P < 0.05). Stroke volume index and left ventricular stroke work index were higher in the esmolol group at 15 min post-CPB (P < 0.05). FAC was higher in the esmolol group at 15 and 30 min post-CPB (P < 0.05), but no difference was observed between groups at 1 h post-CPB. Esmolol infused during CPB in this series of patients was associated with better left ventricular function during the first 0.5 h post-CPB.