How should hypotension be treated in a patient with mitral stenosis?
Hypotension is best treated with an α-adrenergic agonist such as phenylephrine, which would increase arterial pres-sure and decrease heart rate via baroreceptor-mediated reflexes. Vasoconstriction is necessary in this case, because it is essential to preserve vital organ perfusion in the face of a fixed low cardiac output. β-Adrenergic agonists cause tachycardia and vasodilation, which are undesirable effects in mitral stenosis patients. Thus, ephedrine, dopamine, dobutamine, and epinephrine are relatively contraindicated before valvular repair.