EFFECT OF ESMOLOL GIVEN DURING CARDIOPULMONARY BYPASS ON FRACTIONAL AREA OF CONTRACTION FROM TRANSESOPHAGEAL ECHOCARDIOGRAPHY

The infusion of esmolol during hypothermic cardiopulmonary bypass (CPB ) has no negative myocardial effects after CPB, despite increased esmo lol levels during CPB due to hypothermia. The purpose of this randomiz ed, double-blind, prospective study was to measure the effects of esmo lol infused during CPB on cardiac function as measured by calculated i ndices of cardiac work and by transesophageal echocardiography (TEE). Patients scheduled for CPB were randomized to receive intravenous esmo lol (300 mu g . kg(-1). min(-1) during CPB after bolus of 2 mg/kg prio r to CPB) or placebo. Infusion was stopped at 10 min after release of aortic crossclamp. Hemodynamics and TEE were recorded during the proce dure. Fractional area of contraction (FAG), an approximation of left v entricular ejection fraction, was calculated from end-diastolic and en d-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 str oke 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 associ ated with better left ventricular function during the first 0.5 h post -CPB.