High Sensitivity Cardiac Troponin in the Distinction of Acute Myocardial Infarction from Acute Cardiac Non-Coronary Artery Disease.

Circulation. 2012 May 23;

Authors: Haaf P, Drexler B, Reichlin T, Twerenbold R, Reiter M, Meissner J, Schaub N, Stelzig C, Freese M, Heinzelmann A, Meune C, Balmelli C, Freidank H, Winkler K, Denhaerynck K, Hochholzer W, Osswald S, Mueller C

Abstract
BACKGROUND: We hypothesized that high-sensitivity cardiac troponin (hs-cTn) and its early change are useful in distinguishing acute myocardial infarction (AMI) from acute cardiac non-coronary artery disease (CNCD). METHODS AND RESULTS: In a prospective, international multicenter study, hs-cTn was measured with three assays (hs-cTnT, Roche Diagnostics; hs-cTnI, Beckman-Coulter; hs-cTnI Siemens) in a blinded fashion at presentation and serially thereafter in 887 unselected patients with acute chest pain. Accuracy of the combination of presentation values with serial changes was compared against a final diagnosis adjudicated by two independent cardiologists. AMI was the adjudicated final diagnosis in 127 patients (15%), CNCD in 124 (14%). Patients with AMI had higher median presentation values of hs-cTnT (0.113 ug/l [0.049-0.246 ug/l] versus 0.012 ug/l [0.006-0.034 ug/l];p<0.001) and higher absolute changes of hs-cTnT in the first hour (0.019 ug/l [0.007-0.067 ug/l] versus 0.001 ug/l [0-0.003 ug/l];p<0.001) than patients with CNCD. Similar findings were obtained using the hs-cTnI assays. Adding changes of hs-cTn in the first hour to its presentation value yielded a diagnostic accuracy for AMI as quantified by the area under the receiver operating characteristics curve of 0.94 for hs-cTnT (0.92 for both hs-cTnI assays). Algorithms using ST-elevation, presentation values and changes of hs-cTn in the first hour accurately separated patients with AMI and CNCD. These findings were confirmed when the final diagnosis was re-adjudicated using hs-cTnT values and validated in an independent validation cohort. CONCLUSIONS: The combined use of hs-cTn at presentation and its early absolute change excellently discriminate between patients with AMI and CNCD. CLINICAL TRIAL REGISTRATION INFORMATION: clinicaltrials.gov; Identifier: NCT00470587.

PMID: 22623715 [PubMed - as supplied by publisher]

The Relationship Between Chest Compression Rates and Outcomes from Cardiac Arrest.

Circulation. 2012 May 23;

Authors: Idris AH, Guffey D, Aufderheide TP, Brown S, Morrison LJ, Nichols P, Powell J, Daya M, Bigham BL, Atkins DL, Berg R, Davis D, Stiell I, Sopko G, Nichol G

Abstract
BACKGROUND: Guidelines for cardiopulmonary resuscitation (CPR) recommend a chest compression rate of at least 100 compressions/min. Animal and human studies have reported that blood flow is greatest with chest compression rates near 120/min, but few have reported rates used during out-of-hospital (OOH) CPR, or the relationship between rate and outcome. The purpose of this study was to describe chest compression rates used by emergency medical services (EMS) providers to resuscitate patients with OOH cardiac arrest and to determine the relationship between chest compression rate and outcome. METHODS AND RESULTS: Included were patients ? 20 years old with OOH cardiac arrest treated by EMS providers participating in the Resuscitation Outcomes Consortium. Data were abstracted from monitor-defibrillator recordings during CPR. Multiple logistic regression assessed the association between chest compression rate and outcome. From December 2005 to May 2007, 3,098 patients with OOH cardiac arrest were included in this study. Mean age was 67±16 years and 8.6% survived to hospital discharge. Mean compression rate was 112±19/min. A curvilinear association between chest compression rate and return of spontaneous circulation (ROSC) was found in cubic spline models after multivariable adjustment (p = 0.012). ROSC rates peaked at a compression rate of about 125/min and then declined. Chest compression rate was not significantly associated with survival to hospital discharge in multivariable categorical or cubic spline models. CONCLUSIONS: Chest compression rate was associated with ROSC but not with survival to hospital discharge in OOH cardiac arrest.

PMID: 22623717 [PubMed - as supplied by publisher]