PREVALENCE OF RIGHT-VENTRICULAR PERFUSION DEFECTS AFTER INFERIOR MYOCARDIAL-INFARCTION ASSESSED BY LOW-LEVEL EXERCISE WITH TECHNETIUM 99M SESTAMIBI TOMOGRAPHIC MYOCARDIAL IMAGING

To assess the prevalence of right ventricular perfusion defects after a recent inferior wall myocardial infarction, 33 patients were studied 6 to 14 days after infarction with low-level exercise testing and tec hnetium 99m (Tc-99m) sestamibi (SPECT) imaging. Twenty-two control sub jects with a <5% likelihood of coronary artery disease undergoing exer cise Tc-99m sestamibi imaging were also studied. For each image the ri ght ventricle was computer isolated from reconstructed transverse card iac slices, followed by reorientation into oblique slices. Both right and left ventricular images were visually assessed for defects. A quan titative method of defect detection was also applied to the right vent ricle. For the right ventricle, 100% of the stress images and 96% of t he rest images were adequate for interpretation. Right ventricular str ess perfusion defects were identified in 10 (30%) of 33 patients with recent inferior infarction, with 50% completely or partially normalizi ng on rest images, consistent with ischemia. Of 14 patients with left ventricular inferoseptal defects, eight (57%) had right ventricular de fects compared with 2 (11%) of 19 without inferoseptal defects (p < 0. 005). We concluded that the right ventricle can be adequately assessed for perfusion defects by means of exercise with Tc-99m sestamibi SPEC T imaging. Defects of the right ventricle after inferior myocardial in farction occur frequently, and many have evidence of ischemia. Right v entricular perfusion defects are closely associated with left ventricu lar inferoseptal defects.