Dobutamine pharmacodynamics during dobutamine stress echocardiography and the impact of β-blocker withdrawal: A report from the women\u27s ischemic syndrome evaluation study

Study Objectives. To determine the pharmacodynamic parameters of dobutamine during dobutamine stress echocardiography (DSE) and to determine how β-blocker withdrawal the evening before DSE affects responses to dobutamine during DSE. Design. Retrospective analysis. Setting. University medical center. Patients. One hundred thirty-six women who had chest pain or other symptoms suggestive of myocardial ischemia and were considered to have a clinical indication for coronary angiography. Measurements and Main Results. Patients underwent DSE with dobutamine dosages titrated from 5 to 40 pg/kg/minute. The infusion was terminated if the patient reached target heart rate or symptoms developed. Those taking β-blockers withheld their doses the evening before DSE. Traditional pharmacodynamic modeling revealed a wide range in responses to dobutamine. Data for 62% of patients not taking β-blockers were described by the Emax (maximum heart rate response to dobutamine) model, whereas data for only 39% of patients taking β-blockers were best described by this model (p=0.01). Patients taking β-blockers also had a smaller mean increment in left ventricular ejection fraction (10.8% ± 4.2% vs 14.1% ± 9.3%, p\u3c0.01), a trend toward a higher ED50 (dobutamine dosage rate causing half the maximum heart-rate response; median 16.8 pg/kg/min, p=0.12) and a lower sigmoidicity factor determining the shape of the curve (median 2.1, p=0.03). Conclusion. The response to dobutamine exhibits wide interpatient variability, even in the absence of β-blockade. Nonetheless, in the absence of β-blockers, in most patients the dobutamine response reaches a plateau by the time the maximum infusion rate (40 pg/kg/min) is reached. Withdrawal of β-blockers the evening before DSE may be inadequate time for elimination of β-blocker effect, requiring the addition of atropine to achieve the desired response during DSE

Influence of gender and race on hemodynamic response to dobutamine during dobutamine stress echocardiography

This study sought to determine the influence of gender and/or race on the hemodynamic response to dobutamine during dobutamine stress echocardiography. Blood pressure response patterns differed by gender and race, and completion of testing was often limited because of adverse events, namely, hypertension. Gender and racial differences in blood pressure response merit consideration as potential contributors to the suboptimal response in dobutamine stress testing. © 2004 by Excerpta Medica, Inc