CORRELATES OF UNRECOGNIZED ACUTE MYOCARDIAL-INFARCTION DETECTED VIA PERFUSION IMAGING

Research using the electrocardiogram (EGG) indicates that about 1/3 of acute myocardial infarctions (AMIs) are unrecognized. To date, no stu dies of unrecognized AMIs have employed perfusion imaging, although it is more sensitive than the ECG and provides more information about in farct characteristics, such as size and location. In this study, 82 of 258 consecutive patients (31.8%) undergoing exercise testing with tec hnetium-99m sestamibi perfusion imaging had fixed, nonartifactual perf usion defects, suggesting AMI. These patients were interviewed regardi ng their recognition of AMI; 27 patients (32.9%) had unrecognized AMI. Unrecognized AMI was significantly associated with (1) smaller infarc ts, (2) infarcts not in the apical or septal regions, (3) diabetes mel litus, (4) lack of angina, (5) a negative family history for cardiac d isease, and (6) being African-American. Many of these variables were s ignificantly intercorrelated, and in multivariate analysis, unrecogniz ed AMI remained significantly predicted by a smaller infarct and lack of angina. This study suggests that the incidence of unrecognized AMI detected via perfusion imaging on a clinic population is similar to th at detected via electrocardiagraphic studies on community samples. Thi s study also replicates prior findings of the medical history and demo graphic correlates of unrecognized AMI, and indicates that infarct siz e and location are also associated with unrecognized AMI. (C) 1997 by Excerpta Medica, Inc.