Technetium-99m sestamibi uptake after injection at rest is comparable to 201Tl uptake after injection at rest in patients with severe coronary artery disease and left ventricular dysfunction, suggesting comparable worth for viability assessment.

Background: Very low high-sensitivity cardiac troponin T (hs-cTnT) thresholds on presentation can rule out acute myocardial infarction (AMI), but the ability to identify patients at low risk of 30-day major adverse cardiac events (MACE) is less clear. This study examines the sensitivity of low concentrations of hs-cTnT on presentation to rule out 30-day MACE. Methods: This prospective cohort study enrolled patients with chest pain presenting to the emergency department with nonischemic electrocardiograms who underwent AMI rule-out with an hs-cTnT assay. The primary outcome was 30-day MACE; secondary outcomes were individual MACE components. Because guidelines recommend using a CJC Open 1 (2019) 289e296

ABSTRACT Objective Both 1- and 2-hour rapid diagnostic algorithms using high-sensitivity troponin (hs-cTn) have been validated to diagnose acute myocardial infarction (MI), leaving physicians uncertain which algorithm is preferable. The objective of this study was to prospectively evaluate the diagnostic performance of 1- and 2-hour algorithms in clinical practice in a Canadian emergency department (ED). Methods ED patients with chest pain had high-sensitivity cardiac troponin-T (hs-cTnT) collected on presentation and 1- and 2-hours later at a single academic centre over a 2-year period. The primary outcome was index MI, and the secondary outcome was 30-day major adverse cardiac events (MACE). All outcomes were adjudicated. Results We enrolled 608 patients undergoing serial hs-cTnT sampling. Of these, 350 had a valid 1-hour and 550 had a 2-hour hs-cTnT sample. Index MI and 30-day MACE prevalence was ~12% and 14%. Sensitivity of the 1- and 2-hour algorithms was similar for index MI 97.3% (95% CI: 85.8–99.9%) and 100% (95% CI: 91.6–100%) and 30-day MACE: 80.9% (95% CI: 66.7–90.9%) and 83.3% (95% CI: 73.2–90.8%), respectively. Both algorithms accurately identified about 10% of patients as high risk. Conclusions Both algorithms were able to classify almost two-thirds of patients as low risk, effectively ruling out MI and conferring a low risk of 30-day MACE for this group, while reliably identifying high-risk patients. While both algorithms had equivalent diagnostic performance, the 2-hour algorithm offers several practical advantages, which may make it preferable to implement. Broad implementation of similar algorithms across Canada can expedite patient disposition and lead to resource savings.

Introduction: Two published studies reported natriuretic peptides can aid in risk-stratification of Emergency Department (ED) syncope. We sought to assess the role of N-Terminal pro Brain Natriuretic Peptide (NT pro-BNP) to identify syncope patients at risk for serious adverse events (SAE) within 30 days of the ED visit, and its value above that of the Canadian Syncope Risk Score (CSRS). Methods: We conducted a multicenter prospective cohort study at 6 large Canadian EDs from Nov 2011 to Feb 2015. We enrolled adults who presented within 24-hours of syncope and excluded those with persistent altered mentation, obvious seizure, and intoxication. We collected patient characteristics, nine CSRS predictors (includes troponin), ED management and NT pro-BNP levels. Adjudicated serious adverse events (SAE) included death, cardiac SAE (arrhythmias, myocardial infarction, serious structural heart disease) and non-cardiac SAE (pulmonary embolism, severe hemorrhage and procedural interventions within 30-days). We used two tailed t-test and logistic regression analysis. Results: Of the 1359 patients (mean age 57.2 years, 54.7% females, 13.3% hospitalized) enrolled, 148 patients (10.9%; 0.7% deaths, 7.9% cardiac SAE including 6.1% arrhythmia) suffered SAE within 30-days. The mean NT pro-BNP values, when compared to the patients with no SAE (499.8ng/L) was significantly higher among the 56 patients who suffered SAE after ED disposition (3147ng/L, p = 0.001), and among the 35 patients with cardiac SAE after ED disposition (2016.2ng/L, p = 0.02). While there was a trend to higher levels among patients who suffered arrhythmia after the ED visit, it was not statistically significant (1776.4ng/L, p = 0.07). In a model with CSRS predictors, the adjusted odds ratio for NT pro-BNP was 8.0 (95% CI 1.8, 35.9) and troponin was 3.8 (95% CI 1.7, 8.8). The addition of NT pro-BNP did not significantly improve the classification performance (p = 0.76) with areas under the curves for CSRS was 0.91 (95% CI 0.88, 0.95) and CSRS with NT pro-BNP was 0.92 (95% CI 0.88, 0.95). Conclusion: In this multicenter study, mean NT pro-BNP levels were significantly higher among ED syncope patients who suffered SAE including cardiac SAE after ED disposition. Though NT pro-BNP was a significant independent predictor of SAE after ED disposition, it did not improve accuracy in ED syncope riskstratification when compared to CSRS. Hence, we do not recommend NT pro-BNP measurement for ED syncope management. Keywords: syncope, risk stratification, n-terminal pro brain natriuretic peptide LO56External validation of a 1-hour rapid diagnostic algorithm for ruling out acute myocardial infarction in emergency department patients with chest pain using a high-sensitivity troponin-T assay J. E. Andruchow, MD, MSc, T. S. Boyne, MD, S. Vatanpour, PhD, D. Wang, MSc, A. D. McRae, MD, PhD, University of Calgary Department of Emergency Medicine, Alberta Health Services, Calgary, AB Introduction: Ruling out acute myocardial infarction (AMI) using serial troponin testing is central...