Prevalence and factors associated with false-positive ST-segment elevation myocardial infarction diagnoses at primary percutaneous coronary intervention–capable centers: a report from the Activate-SF registry.

BACKGROUND: Rapid activation of the cardiac catheterization laboratory for primary percutaneous coronary intervention (PCI) improves outcomes for ST-segment elevation myocardial infarction (STEMI), but selected emphasis on minimizing time to reperfusion may lead to a greater frequency of false-positive activations.
METHODS: We analyzed consecutive patients referred for primary PCI for a possible STEMI at 2 centers from October 2008 to April 2011. "False-positive STEMI activation" was defined as lack of a culprit lesion by angiography or by assessment of clinical, electrocardiographic, and biomarker data in the absence of angiography. Clinical and electrocardiographic factors associated with false-positive activations were evaluated in a backward stepwise selection bootstrapped logistic regression model.
RESULTS: Of 411 STEMI activations by emergency physicians, 146 (36%) were deemed to be false-positive activations. Structural heart disease and heart failure were the most common diagnoses among false-positive activations. Electrocardiographic left ventricular hypertrophy (adjusted odds ratio [AOR], 3.15; 95% CI, 1.55-6.40; P=.001), a history of coronary disease (AOR, 1.93; 95% CI, 1.04-3.59; P=.04), or prior illicit drug abuse (AOR, 2.67; 95% CI, 1.13-6.26; P=.02) independently increased the odds of false-positive STEMI activations. Increasing body mass index decreased the odds of a false-positive activation (AOR, 0.91; 95% CI, 0.86-0.97; P=.004), as did angina at presentation (AOR, 0.28; 95% CI, 0.14-0.57; P < .001).
CONCLUSIONS: More than a third of patients referred for primary PCI from the emergency department did not have a STEMI. Multiple patient-level characteristics were significantly associated with an increased odds of false-positive STEMI activation.