DIAGNOSIS OF CORONARY-ARTERY DISEASE BY EXERCISE TL-201 TOMOGRAPHY INPATIENTS WITH A RIGHT-VENTRICULAR PACEMAKER

Objectives. We sought to study the accuracy of exercise perfusion scin tigraphy in patients with an implanted apical right ventricular pacema ker. Background. The specificity of exercise perfusion scintigraphy is decreased in patients with a left bundle branch block. Patients with a permanent ventricular pacemaker have a similar conduction abnormalit y that may also potentially result in similar false positive perfusion defects, Methods. One hundred five patients with a right ventricular pacemaker underwent exercise thallium-201 tomography and coronary angi ography within 7 days of each other. Patients with a previous myocardi al infarction were excluded. Results. Patients were classified into fo ur groups according to the agreement or disagreement between the thall ium tomographic and coronary angiographic results. Only 8% of patients ,vith normal results by both techniques were continuously paced during exercise, compared with 78% of patients with normal angiographic resu lts but abnormal scintigraphic results. The mean defect size was 12% i n the latter group. Most of the false positive defects were localized to the inferoposterior (71%), apical (50%) and inferoseptal (28%) wall s. Conclusions. Patients who are paced in the right ventricular apex a nd who continue to be paced throughout exercise have a high incidence of false positive thallium-201 single-photon emission computed tomogra phic defects. (C) 1997 by the American College of Cardiology.