Characteristics and prognosis in patients with false-positive ST-elevation myocardial infarction in the ED

Background There are several causes of ST-segment elevation (STE) besides acute myocardial infarction (MI). Objectives We design this study to determine the prevalence, etiology, clinical manifestation, electrocardiographic characteristics, and outcome in patients with false-positive STEMI. Methods This is a retrospective case-control study design. At our emergency department, 297 patients who underwent emergent coronary angiography for suspected STEMI were enrolled from January 2004 to December 2010. Results Of the 297 patients who underwent coronary angiography, 31 patients (10.4%) did not have a clear culprit coronary lesion and were classified as false-positive STEMI. False-positive STEMI patients had a lower incidence of typical chest pain or chest tightness (58.1% vs 87.6%, P < .001). Inferior STE occurred significantly more often in the patients with true-positive STEMI (49.6% vs 25.8%, P = .012), and diffuse STE, more often in the patients with false-positive STEMI (19.4% vs 0.38%, P = .001). Total height of STE was lower in false-positive STEMI patients (7.5 ± 4.9 vs 10.9 ± 7.9 mm, P = .002) if excluding 5 patients of marked STE just after cardiopulmonary resuscitation. Concave STE and no reciprocal ST-segment depression occurred more often in false-positive STEMI patients (51.6% vs 24.1%, P = .001; 64.5% vs 19.2%, P < .001). There was no significant difference of in-hospital major adverse events in the patients with false-positive and true-positive STEMI. Conclusions The diagnosis of false-positive STEMI is not uncommon. Detailed clinical evaluation and electrocardiogram interpretation may avoid partly unnecessary catheterization laboratory activation.