Early deterioration followed by improvement in contractility during dobutamine stress echocardiography: An unusual response

In 2 patients with severe proximal coronary artery stenosis and normal wall motion in this territory, we observed marked wall motion abnormalities wit h low and intermediate doses of dobutamine, followed by marked improvement with continued dobutamine infusion This unusual response suggests ischemic preconditioning and recruitment of coronary collaterals and would be recogn ized only by monitoring of images obtained at all stages of dobutamine infu sion.