Diagnosis of coronary artery disease in patients with permanent cardiac pacemaker by dobutamine stress echocardiography or exercise thallium-201 myocardial tomography

This study evaluated the use of dobutamine stress echocardiography and exer cise thallium-201 myocardial computed tomography (CT) in the diagnosis of c oronary artery disease (CAD) in patients with permanent transvenous pacemak er with the electrode implanted in the right ventricle (RV). Twenty-nine co nsecutive patients with pacemaker underwent dobutamine stress echocardiogra phy, exercise thallium-201 myocardial CT, and coronary arteriography over a period of 8 +/- 1 days. None of these patients had suffered a myocardial i nfarction (MI). The cardiac rhythm of every patient was electrically paced during echocardiography and tomography. Sixteen. (55%) patients showed CAD on angiography (stenosis greater than or equal to 50% of the luminal diamet er of a major epicardial vessel). The detection sensitivity for CAD was 94% for the tomography and 88% for the echocardiography (P = NS). The differen ce between the sensitivities of the true techniques in detecting CAD based on the affected coronary artery was not statistically significant. Of the 1 3 patients without CAD, tomography showed a positive result in nine cases, i.e., a specificity of 31%, whereas echocardiography showed a positive resu lt in only one case, i.e., a specificity of 92% (P < 0.01). Exercise thalli um-201 myocardial computed tomography produces an increased rate of false-p ositive results in patients with permanent transvenous cardiac pacemaker (P CP) implanted in the right ventricle (RV). Dobutamine stress echocardiograp hy can. thus be used to reduce considerably the level of false-positive res ults in these patients and still retain, a detection sensitivity for CAD eq ual to that of myocardial tomography.