BACKGROUND: Determining the precise magnitude, duration, and mechanism of hypotension caused by intravenous amiodarone could potentially increase the safety of drug administration to critically ill patients. The objective of this study was to characterize the immediate cardiovascular actions of an intravenous loading dose of amiodarone administered using echocardiographic and hemodynamic measurements.

METHODS: In a prospective double-blind trial, 20 patients undergoing off-pump coronary artery bypass graft surgery were randomly assigned to receive intravenous amiodarone (n = 10) or placebo (n = 10). Heart rate (HR), arterial blood pressure (systolic, diastolic, mean; SAP, DAP, MAP), pulmonary artery pressure (systolic, diastolic, mean; PSAP, PDAP, PMAP), cardiac output (CO), central venous pressure (CVP), left ventricular ejection fraction (LVEF) were measured.

RESULTS: HR, SAP, DAP, MAP, PSAP, PDAP, PMAP, CO by thermodilution method, CVP, LVEF by echocardiographic measurements was not significantly different in both group. Hypotension requiring intervention occurred in 2 of 10 patients after amiodarone administration and in none of 10 patients after placebo.

CONCLUSIONS: Hypotension requiring intervention occurred 20% after amiodarone administration, the cause of these hypotension were thought to be arterial dilatation but was not associated with decreased cardiac output or left ventricular ejection fraction and corrected successfully by intravenous administration of phenylephrine.