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The protocol for dobutamine stress echocardiography for evaluation of AS severity in setting of LV dysfunction uses a low dose starting at 2.5 or 5 µg/kg/min with an incremental increase in the infusion every 3–5 min to a maximum dose of 10–20 µg/kg/min. There is a risk of arrhythmia so there must be medical supervision and high doses of dobutamine should be avoided. The infusion should be stopped as soon as a positive result is obtained or when the heart rate begins to rise more than 10–20 bpm over baseline or exceeds 100 bpm, on the assumption that the maximum inotropic effect has been reached. In addition, dobutamine administration should also be terminated when symptoms, blood pressure fall, or significant arrhythmias occur.