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Current guidelines advocate primary percutaneous coronary intervention as the therapy of choice for ST-segment elevation myocardial infarction (STEMI) when available. Little is known about the outcomes of patients without a culprit lesion after referral for primary percutaneous coronary intervention for a presumed STEMI. Subjects were identified within a registry containing consecutive patients who underwent emergent angiography for a potential STEMI from October 2008 to July 2012. Vital status was obtained from the medical record and Social Security Death Index. Cox proportional hazards models were created to evaluate the relation between the angiographic findings and cardiovascular outcomes, including major adverse cardiovascular events (MACE) and mortality. Among 539 patients who underwent emergent angiography, 65 (12%) had no coronary artery disease (CAD), 110 (20%) had CAD without a culprit lesion, and 364 (68%) had a culprit lesion. Kaplan-Meier analysis of MACE demonstrated that patients with CAD who lack a culprit lesion had a similar rate of MACE to those with a culprit lesion (p = 0.64), and both groups had significantly increased risk compared with those with no CAD (hazard ratio [HR] 1.9, 95% confidence interval [CI] 1.01 to 3.41 and HR 2.0, 95% CI 1.15 to 3.54, respectively). Kaplan-Meier analysis of mortality illustrated a nonsignificant trend toward increased mortality in patients having a culprit lesion (HR 1.7, 95% CI 0.59 to 4.80) and those having CAD without a culprit lesion (HR 1.2, 95% CI 0.39 to 3.81) compared with those with no CAD. In conclusion, patients found to have CAD without a culprit lesion in emergent angiography after a presumptive STEMI diagnosis have similar long-term rates of MACE compared with those requiring emergent revascularization., (Copyright © 2013 Elsevier Inc. All rights reserved.)

Background: With adoption of telemedicine, physicians are increasingly asked to diagnose ST-segment elevation myocardial infarctions (STEMIs) based on electrocardiograms (ECGs) with minimal associated clinical information. We sought to determine physicians' diagnostic agreement and accuracy when interpreting potential STEMI ECGs., Methods and Results: A cross-sectional survey was performed consisting of 36 deidentified ECGs that had previously resulted in putative STEMI diagnoses. Emergency physicians, cardiologists, and interventional cardiologists participated in the survey. For each ECG, physicians were asked, "based on the ECG above, is there a blocked coronary artery present causing a STEMI?" The reference standard for ascertaining the STEMI diagnosis was subsequent emergent coronary arteriography. Responses were analyzed with generalized estimating equations to account for nested and repeated measures. One hundred twenty-four physicians interpreted a total of 4392 ECGs. Among all physicians, interreader agreement (kappa) for ECG interpretation was 0.33, reflecting poor agreement. The sensitivity to identify "true" STEMIs was 65% (95% CI: 63 to 67) and the specificity was 79% (95% CI: 77 to 81). There was a 6% increase in the odds of accurate ECG interpretation for every 5 years of experience since medical school graduation (OR 1.06, 95% CI: 1.02 to 1.10, P = 0.01). After adjusting for experience, there was no significant difference in the odds of accurate interpretation by specialty-Emergency Medicine (reference), General Cardiology (AOR 0.97, 95% CI: 0.79 to 1.2, P = 0.80), or Interventional Cardiology physicians (AOR 1.24, 95% CI: 0.93 to 1.7, P = 0.15)., Conclusions: There is significant physician disagreement in interpreting ECGs with features concerning for STEMI. Such ECGs lack the necessary sensitivity and specificity to act as a suitable "stand-alone" diagnostic test.

Background: An isolated posterior myocardial infarction (PMI) is associated with significant morbidity and mortality. Because physicians often fail to recognize this diagnosis, there may be delays in the timely revascularization of these patients. The present study sought to identify the clinical characteristics and reperfusion times among patients presenting with isolated PMI., Methods: We identified subjects with isolated PMI within a registry of all catheterization laboratory activations for ST-elevation myocardial infarction (STEMI) from 2008 to 2012. Association between PMI and revascularization within 90 minutes was evaluated by logistic regression., Results: Among 318 patients who underwent revascularization for STEMI, a total of 20 (6%) had electrocardiographic evidence of an isolated PMI. Compared to non-PMI STEMI, subjects with PMI were more often female (45% vs 22%; P=.02) and less likely to have chest pain (40% vs 75%; P<.01). The median door-to-activation (25.5 min vs 12 min; P<.01), activation-to-laboratory (36.5 min vs 29 min; P<.01) and door-to-balloon times (107 min vs 72 min; P<.01) were longer among subjects with PMI, with fewer patients achieving reperfusion within 90 minutes (30% vs 71%; P<.01). After multivariable adjustment, individuals with PMI had 82% lower odds (adjusted odds ratio, 0.18; 95% confidence interval, 0.06-0.50) of achieving coronary reperfusion within 90 minutes. Door-to-activation time accounted for 96% of variation in the total revascularization time (R²=0.96; P<.0001)., Conclusions: Door-to-activation time was prolonged for those with PMI, resulting in longer door-to-balloon times and fewer patients revascularized within the recommended time. An isolated PMI should be considered among individuals presenting with symptoms consistent with myocardial infarction.

Prompt percutaneous coronary intervention is associated with improved survival in patients presenting with cardiac arrest. Few studies, however, have focused on patients with cardiac arrest not selected for coronary angiography. The aim of the present study was to evaluate the clinical characteristics and outcomes of patients with cardiac arrest denied emergent angiography. Patients with cardiac arrest were identified within a registry that included all catheterization laboratory activations from 2008 to 2012. Logistic regression and proportional-hazards models were created to assess the clinical characteristics and mortality associated with denying emergent angiography. Among 664 patients referred for catheterization, 110 (17%) had cardiac arrest, and 26 of these patients did not undergo emergent angiography. Most subjects (69%) were turned down for angiography for clinical reasons and a minority for perceived futility (27%). After multivariate adjustment, pulseless electrical activity as the initial arrest rhythm (adjusted odds ratio [AOR] 13.27, 95% confidence interval [CI] 1.76 to 100.12), <1.0 mm of ST-segment elevation (AOR 10.26, 95% CI 1.68 to 62.73), female gender (AOR 4.45, 95% CI 1.04 to 19.08), and advancing age (AOR 1.10 per year, 95% CI 1.04 to 1.16) were associated with increased odds of withholding angiography. The mortality rate was markedly higher for patients who were denied emergent angiography (hazard ratio 3.64, 95% CI 2.05 to 6.49), even after adjustment for medical acuity (hazard ratio 2.29, 95% CI 1.19 to 4.41). In conclusion, older subjects, women, and patients without ST-segment elevation were more commonly denied emergent angiography after cardiac arrest. Patients denied emergent angiography had increased mortality that persisted after adjustment for illness severity., (Copyright © 2013 Elsevier Inc. All rights reserved.)

Patients with electrocardiographic (ECG) left ventricular hypertrophy (LVH) have repolarization abnormalities of the ST segment that may be confused with an ischemic current of injury. We analyzed the ACTIVATE-SF database, a registry of consecutive emergency department ST-segment elevation (STE) myocardial infarction diagnoses from 2 medical centers. Univariate analysis was performed to identify ECG variables associated with presence of an angiographic culprit lesion. Recursive partitioning was then applied to identify a clinical decision-making rule that maximizes sensitivity and specificity for presence of an angiographic culprit lesion. Seventy-nine patients with ECG LVH underwent emergency cardiac catheterization for primary angioplasty. Patients with a culprit lesion had greater magnitude of STE (3.0 ± 1.8 vs 1.9 ± 1.0 mm, p = 0.005), more leads with STE (3.1 ± 1.6 vs 2.0 ± 1.8 leads, p = 0.002), and a greater ratio of STE to R-S-wave magnitude (median 25% vs 9.2%, p = 0.003). Univariate application of ECG criteria had limited sensitivity and a high false-positive rate for identifying patients with an angiographic culprit lesion. In patients with anterior territory STE, using a ratio of ST segment to R-S-wave magnitude ≥25% as a diagnostic criteria for STE myocardial infarction significantly improved specificity for an angiographic culprit lesion without decreasing sensitivity (c-statistic 0.82), with a net reclassification improvement of 37%. In conclusion, application of an ST segment to R-S-wave magnitude ≥25% rule may augment current criteria for determining which patients with ECG LVH should undergo primary angioplasty., (Copyright © 2012 Elsevier Inc. All rights reserved.)

Background: Little is known about the components of door-to-balloon time among patients with ST-segment elevation myocardial infarction undergoing primary percutaneous coronary intervention. We assessed the role of time from hospital arrival to ST-segment elevation myocardial infarction diagnosis (door-to-activation time) on door-to-balloon time in contemporary practice and evaluated factors that influence door-to-activation times., Methods and Results: Registry data on 347 consecutive patients diagnosed with a ST-segment elevation myocardial infarction in the emergency department over 30 months at 2 urban primary percutaneous coronary intervention centers were analyzed. The primary study end point was the time from hospital arrival to catheterization laboratory activation by the emergency department physician, and we assessed factors associated with this period. Door-to-balloon time and its other components were secondary study end points. The median door-to-activation time was 19 minutes (interquartile range, 9-54). Variation in door-to-activation times explained 93% of the variation in door-to-balloon times and demonstrated the strongest correlation with door-to-balloon times (r=0.97). Achieving a door-to-activation time of ≤20 minutes resulted in an 89% chance of achieving a door-to-balloon time of ≤90 minutes compared with only 28% for patients with a door-to-activation time >20 minutes. Factors significantly associated with door-to-activation time include the following: prehospital ECG use (61% shorter, 95% confidence interval, -50 to -72%; P<0.001) and computed tomography scan use in the emergency department (245% longer, 95% confidence interval, +50 to +399%; P=0.001)., Conclusions: The interval from hospital arrival to ST-segment elevation myocardial infarction diagnosis and catheterization laboratory activation (door-to-activation time) is a strong driver of overall door-to-balloon times. Achieving a door-to-activation time ≤20 minutes was key to achieving a door-to-balloon time ≤90 minutes. Delays in door-to-activation time are not associated with delays in other aspects of the primary percutaneous coronary intervention process.

Patients presenting with suspected ST-segment elevation myocardial infarction (STEMI) may have important alternative diagnoses (e.g., aortic dissection, pulmonary emboli) or safety concerns for STEMI management (e.g., head trauma). Computed tomographic (CT) scanning may help in identifying these alternative diagnoses but may also needlessly delay primary percutaneous coronary intervention (PCI). We analyzed the ACTIVATE-SF Registry, which consists of consecutive patients with a clinical diagnosis of STEMI admitted to the emergency departments of 2 urban hospitals. Of 410 patients with a suspected diagnosis of STEMI, 45 (11%) underwent CT scanning before primary PCI. Presenting electrocardiograms, baseline risk factors, and presence of an angiographic culprit vessel were similar in those with and without CT scanning before PCI. Only 2 (4%) of these CT scans changed clinical management by identifying a stroke. Patients who underwent CT scanning had far longer door-to-balloon times (median 166 vs 75 minutes, p <0.001) and higher in-hospital mortality (20% vs 7.8%, p = 0.006). After multivariate adjustment, CT scanning in the emergency department before primary PCI remained independently associated with longer door-to-balloon times (100% longer, 95% confidence interval 60 to 160, p <0.001) but was no longer associated with mortality (odds ratio 1.4, p = 0.5). In conclusion, CT scanning before primary PCI rarely changed management and was associated with significant delays in door-to-balloon times. More judicious use of CT scanning should be considered., (Copyright © 2012 Elsevier Inc. All rights reserved.)

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.

Early in the course of ST-segment elevation myocardial infarction (STEMI), therapies that may harm patients who develop left ventricular (LV) dysfunction, such as β-blockers, are often administered. The investigators analyzed the ACTIVATE-SF database, a registry of consecutive STEMI activations presenting to 2 medical centers at the University of California, San Francisco. LV dysfunction was defined as an ejection fraction ≤40% on echocardiography. Of 211 patients included in the analysis, 66 (31%) had LV ejection fractions ≤40%. Patients with LV dysfunction were older (63 ± 15 vs 56 ± 13 years, p = 0.002). In multivariate regression models, decreased renal function (reference group, creatinine <1.0 mg/dl; adjusted odds ratio [AOR] creatinine >1.5 mg/dl 6.35, 95% confidence interval [CI] 1.66 to 24.31, p = 0.007), a history of coronary artery disease (AOR 3.12, 95% CI 1.26 to 7.71, p = 0.014), ST-segment elevation >2 mm on 12-lead electrocardiography (AOR 2.78, 95% CI 1.31 to 5.87, p = 0.008), and need for mechanical ventilation (AOR 3.98, 95% CI 1.41 to 11.19, p = 0.009) increased the odds of LV dysfunction. Inferior ST-segment elevations were associated with 88% decreased odds of LV dysfunction (AOR 0.12, 95% CI 0.06 to 0.35, p <0.001). A prediction score using these characteristics stratified patients into low-, intermediate-, and high-risk groups for LV dysfunction; positive likelihood ratios for LV dysfunction in these groups were 0.07, 1.14, and 4.93, respectively. In conclusion, 5 key predictors of in-hospital LV dysfunction after STEMI were identified; a risk score based on these predictors helps to quickly identify patients presenting with STEMI who are at the highest risk for developing significant LV dysfunction and could guide optimal therapeutic choices., (Copyright © 2012 Elsevier Inc. All rights reserved.)