Using a high-frequency linear transducer (15L8), we studied 1) the feasibility of performing echocardiography in nonanesthetized mice compared with mice given pentobarbital sodium (Pento) or a mixture of ketamine and xylazine and 2) the feasibility of echocardiographic evaluation of left ventricular (LV) hypertrophy, dilatation, and function in mice with two-kidney, one-clip hypertension or myocardial infarction (MI). Heart rate (HR) in awake mice was 658 +/- 9 beats/min; Pento and ketamine plus xylazine reduced HR to 377 +/- 11 and 293 +/- 19 beats/min, respectively, associated with a significant decrease in shortening fraction (SF), ejection fraction (EF), and cardiac output (CO) and an increase in LV end-diastolic (LVEDD) and end-systolic dimensions (LVESD). Mice with 4 wk of two-kidney, one-clip hypertension had increased LV mass (15.62 +/- 0. 62 vs. 22.17 +/- 1.79 mg) without altered LV dimensions, SF, EF, or CO. Mice studied 4 wk post-MI exhibited obvious LV dilatation and systolic dysfunction, as evidenced by increased LVEDD and LVESD and decreased SF, EF, and CO. Our findings clearly show the adverse impact of anesthesia on basal cardiac function and the difficulty in interpreting data obtained from anesthetized mice. We believe this is the first study to demonstrate the feasibility of using echocardiography to assess cardiovascular function in the nonanesthetized mouse.
SummaryBackground: Elevated troponin I has been associated with increased mortality in critically ill patients without acute coronary syndrome (ACS). However, the prognostic significance of troponin elevation in patients with diabetic ketoacidosis (DKA) without evident ACS has not been studied.Methods: Retrospective study of all patients admitted to a U.S. tertiary center between 01/98 and 12/00 with DKA and had troponin I level measured. Patients with evidence of ACS or who met the American College of Cardiology/European Society of Cardiology (ACC/ESC) definition for myocardial infarction were excluded. Baseline characteristics, cardiac evaluation and 2 year major adverse coronary event (MACE) rate were compared between patients with positive and negative troponin.Results: Ninety-six patients fulfilled the inclusion criteria of this study, 26 had positive troponin. There were no differences in baseline characteristics between the two groups. After a 2 year follow-up, there was significantly increased mortality in patients with elevated troponin (50.0% versus 27.1%, hazard-ratio (HR) 2.3, 95% confidence intraval (CI) 1.2-4.8, p = 0.02). Patients with elevated troponin also had significantly increased MACE rate at 2 years (50.0% versus 28.6%, HR 2.6, 95% CI 1.3-5.3, p = 0.007) driven primarily by mortality. Using
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