The sensitivity of cardiac markers stratified by symptom duration.

We compared the sensitivity of three commonly used cardiac markers between two subpopulations, those who came to the Emergency Department (ED) late (6-24 h) after their symptoms began, and those who arrived earlier (<6 h), in a prospective comparative trial. Among all adult patients who presented to our ED with symptoms suggestive of acute myocardial infarction (MI), we drew serum for myoglobin, CK-MB, and troponin I upon arrival (time 0) and 2 h later. Outcomes, including acute MI, were determined. Sensitivities for all three markers between the subpopulations who arrived fewer than 6 h from symptom onset were compared to those who arrived later (6-24 h). We enrolled 346 eligible subjects, 36% of whom described cardiac symptoms as beginning 6 or more hours earlier; 14% suffered acute MIs. For time 0, the sensitivity of all three markers for acute MI was significantly higher among those subjects with symptoms of 6 or more hours' duration as compared to those with less. For troponin I, the increase in sensitivity between these two subpopulations approached 300%. At the time of the 2-h sample, the differences in sensitivities were much less and were not statistically significant. We conclude that cardiac marker values obtained at time 0 among Emergency Department patients who arrive 6 or more hours after cardiac symptom onset provide significantly higher sensitivities as compared to those obtained in patients who arrive earlier. For troponin I, the increase in sensitivity approaches threefold.

Disagreement between formal and medical record criteria for the diagnosis of acute coronary syndrome.

OBJECTIVES: To measure agreement between formal and medical record criteria for the diagnosis of acute coronary syndrome (ACS) among patients undergoing an emergency department evaluation for potential acute coronary symptoms. METHODS: Cases of ACS were determined by both formal (World Health Organization 1984 criteria for acute myocardial infarction [AMI], Braunwald criteria for unstable angina pectoris [UAP]) and medical record criteria. In the latter, a diagnosis was made if providers indicated AMI or UAP anywhere in the medical record. All information included in formal criteria was available to clinicians establishing the medical record diagnosis. The two criteria for diagnosis were compared, and a kappa value was recorded. Two blinded observers adjudicated discordant cases, with a kappa value recorded. Disagreements between these two coinvestigators were resolved by a Delphi technique. RESULTS: A total of 375 eligible subjects were enrolled, of whom 65 (17%; 45 AMI, 20 UAP) had ACS by both sets of criteria. Formal and medical record criteria disagreed in 32 subjects. This represented 9% (95% confidence interval = 6% to 12%) of the overall study population but 33% (95% confidence interval = 23% to 43%) of subjects with possible ACS. Coinvestigators acting as judges and blinded to each other's determinations agreed that 25 of these subjects had ACS and three did not; they disagreed on four subjects (kappa = 0.54). Among these four subjects, a Delphi consensus technique determined that two subjects had AMI and two had no ACS. CONCLUSIONS: In a single-site study, among subjects who have possible ACS as determined by either or both formal and medical record criteria, these two sets of criteria disagree in almost one third of cases. Among discordant cases, even two expert judges frequently disagreed on the final diagnosis. A modified Delphi technique to address these disagreements is described.

Predictors of delay in presentation to the ED in patients with suspected acute coronary syndromes.

Delays in seeking medical attention for patients with acute coronary syndromes (ACS) preclude early application of life-saving treatment and diminish efficacy. Previous studies suggest 3-hour delays between onset of symptoms and ED arrival in patients with typical presentations of acute myocardial infarction (AMI). A prospective observational study was conducted in an urban ED measuring lag time (LT) among adults presenting within 48 hours of onset of symptoms suggestive of ACS. Univariate and multiple regression analyses were performed on 5 predictors: age, sex, symptoms at presentation, and 2 different outcomes (AMI and ACS). Three hundred seventy-four patients were enrolled. Mean age was 63 years with 38% 70 years or older. Seventy-three percent of all patients with suspected ACS presented with chest pain, 27% with atypical symptoms. Overall mean LT was 8.7 hours (standard deviation 11). In subgroup analysis, patients aged >/=70 years were more likely to have LTs >12 hours (29% vs. 19% P =.043) and patients without chest pain had longer mean LTs (11.6 vs. 7.6 hours, P =.01). Delay in ED presentation is group specific. Advanced age and patients with atypical symptoms are predictive of longer LTs. Contrary to previously published data, patients with symptoms suspicious for ACS can delay an average of 9 hours, which might alter current thinking in the prevention and care of these patients.