title: Use of the peak troponin value to differentiate myocardial infarction from reversible neurogenic left ventricular dysfunction associated with aneurysmal subarachnoid hemorrhage.
abstract: OBJECTIVE
  Differentiating myocardial infarction (MI) from reversible neurogenic left ventricular dysfunction (stunned myocardium [SM]) associated with aneurysmal subarachnoid hemorrhage (SAH) is critical for early surgical intervention. The authors hypothesized that the cardiac troponin (cTn) trend and/or echocardiogram could be used to differentiate between the two entities.
  
  
  METHODS
  A retrospective study was conducted for the period between 1995 and 2000. All patients included in the study met the following criteria: 1) no history of cardiac problems; 2) new onset of abnormal cardiac function (ejection fraction [EF] < 40% on echocardiograms); 3) serial cardiac markers (cTn and creatine kinase MB isoform [CK-MB]); 4) surgical intervention for their aneurysm; and 5) cardiac output monitoring either by repeated echocardiograms or invasive hemodynamic monitoring during the first 4 days post-SAH when the patients were euvolemic. Of the 350 patients with SAH, 10 (2.9%) had severe cardiac dysfunction. Of those 10, six were women and four were men. The patients' mean age was 53.5 years (range 29-75 years) and their SAH was classified as Hunt and Hess Grade III or IV. Aneurysm distribution was as follows: basilar artery tip (four); anterior communicating artery (two); middle cerebral artery (one); posterior communicating artery (two); and posterior inferior cerebellar artery (one). The mean EFonset was 33%. The changes on echocardiograms in these patients did not match the findings on electrocardiograms (EKGs). Within 4.5 days, dramatic improvement was seen in cardiac output (from 4.93 +/- 1.16 L/minute to 7.74 +/- 0.88 L/minute). Compared with historical controls in whom there were similar levels of left ventricular dysfunction after MI, there was no difference in peak CK-MB. A 10-fold difference, however, was noted in cTn values (0.22 +/- 0.25 ng/ml; control 2.8 ng/ml; p < 0.001).
  
  
  CONCLUSIONS
  The authors determined the following: 1) that the CK-MB trend does not allow differentiation between SM and MI; 2) that echocardiograms revealing significant inconsistencies with EKGs are indicative of SM; and 3) that cTn values less than 2.8 ng/ml in patients with EFs less than 40% are consistent with SM.
authors.affiliation: Department of Surgery Neurosurgery, Duke University Medical Center, Durham, North Carolina 27710, USA. krb1@acpub.duke.edu
authors.forename: Ketan R
authors.initials: KR
authors.lastname: Bulsara
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: McGirt
authors.forename: Lawrence
authors.initials: L
authors.lastname: Liao
authors.forename: Alan T
authors.initials: AT
authors.lastname: Villavicencio
authors.forename: Cecil
authors.initials: C
authors.lastname: Borel
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Alexander
authors.forename: Allan H
authors.initials: AH
authors.lastname: Friedman
mesh_terms: D000328:Adult; D000368:Aged; D002302:Cardiac Output; D003937:Diagnosis, Differential; D004452:Echocardiography; D004562:Electrocardiography; D005260:Female; D006801:Humans; D002532:Intracranial Aneurysm / Q000150:complications*; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000175:diagnosis*; D017682:Myocardial Stunning / Q000097:blood / Q000175:diagnosis / Q000209:etiology; D012189:Retrospective Studies; D013345:Subarachnoid Hemorrhage / Q000150:complications* / Q000209:etiology*; D013997:Time Factors; D014336:Troponin / Q000097:blood*; D018487:Ventricular Dysfunction, Left / Q000097:blood / Q000175:diagnosis* / Q000209:etiology*
chemical_list: D014336:Troponin