EFFECT OF DOBUTAMINE STRESS ECHOCARDIOGRAPHY ON MITRAL REGURGITATION

Objectives. This study was performed to examine the effect of dobutami ne stress echocardiography on mitral regurgitation and to test the hyp othesis that mitral regurgitation will increase in patients with an is chemic response. Background. New or worsening mitral regurgitation dur ing stress testing has been proposed as a marker of ischemia. However, it is unclear whether ischemia induced by dobutamine is associated wi th mitral regurgitation because the hemodynamic effects of dobutamine may vary with regard to mitral regurgitation, depending on left ventri cular function and maximal dose attained. Methods. Dobutamine stress e chocardiography was performed in 102 consecutive patients with suspect ed or known coronary artery disease. Color flow Doppler was used to de termine the presence and change in mitral regurgitation at baseline an d peak dobutamine infusion (up to 40 mu g/kg body weight per min). The mitral regurgitation color flow Doppler area was semiquantitatively g raded as mild (<4 cm(2)), moderate (4 to g cm(2)) or severe (>8 cm(2)) . Patients were assigned to ischemic and nonischemic groups according to the dobutamine stress echocardiographic results. Results. The two g roups achieved the same maximal dose and demonstrated similar blood pr essure and heart rate responses to dobutamine infusion. Only two patie nts developed new mitral regurgitation during dobutamine infusion, and both had a normal dobutamine echocardiographic result. More patients without ischemia had no mitral regurgitation compared with patients wi th ischemia. There was an insufficient number of patients with coronar y angiographic data to determine the effects of mitral regurgitation o n the sensitivity and specificity of dobutamine stress echocardiograph y. Of 23 patients with a rest ejection fraction <50%, 61% had an impro vement in mitral regurgitation grade compared with 25% of patients wit h a rest ejection fraction greater than or equal to 50% (p < 0.02). Co nclusions. These data indicate that although dobutamine infusion often improves mitral regurgitation in patients with left ventricular dysfu nction during stress echocardiography, it does not induce or worsen mi tral regurgitation in those who demonstrate an ischemic response. Futu re studies are necessary, with larger numbers of patients, to determin e the effects of mitral regurgitation on the sensitivity and specifici ty of dobutamine stress echocardiography.