[Dobutamine stress echocardiography in the diagnosis of myocardial ischemia in patients with implanted pacemakers: report of two cases].

Dobutamine stress echocardiography was used in the diagnosis of myocardial ischemia in patients with implanted VVI pacemakers. A 69-year-old woman received a pacemaker for Mobitz II type AV block in October 1992. She had suffered from chest pain during effort since January 1993 and underwent dobutamine stress echocardiography in April 1993. Although the electrocardiogram failed to identify ischemia because of the pacemaker rhythm, ischemia of the anterior wall was revealed as a worsening of the wall motion on the echocardiogram. The coronary angiogram showed 99% stenosis of the left descending artery. A direct coronary atherectomy was performed on the lesion. A 68-year-old man received a pacemaker for sick sinus syndrome in August 1993. He had suffered from chest oppression during effort since May 1992 and underwent dobutamine stress echocardiography in October 1993. Spontaneous rhythm appeared with dobutamine infusion, but the electrocardiogram could not demonstrate ischemia because of incomparability with the rhythm at rest. Echocardiography detected a new wall motion abnormality of the inferior wall caused by dobutamine. The coronary angiogram showed 90% stenosis of the right coronary artery. PTCA was performed on the lesion. Dobutamine stress echocardiography is useful for the diagnosis of myocardial ischemia in patients with implanted pacemakers.