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| *Abbreviated ''MI''. | | *Abbreviated ''MI''. |
| *[[AKA]] ''myocardial infarct''. | | *[[AKA]] ''myocardial infarct''. |
| ===Clinical===
| | {{Myocardial infarction}} |
| *Usually diagnosed clinically - with blood work (troponin, CK-MB) or EKG.
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| *MI may be precipitated by cocaine use... and further exacerbated by treatment with a beta-blocker.<ref name=pmid19127137>{{cite journal |author=Mohamad T, Kondur A, Vaitkevicius P, Bachour K, Thatai D, Afonso L |title=Cocaine-induced chest pain and beta-blockade: an inner city experience |journal=Am J Ther |volume=15 |issue=6 |pages=531-5 |year=2008 |pmid=19127137 |doi=10.1097/MJT.0b013e3181758cfc |url=}}</ref>
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| *Acute myocardial infarction (abbreviated AMI) = MI < 6 hours old.<ref name=pmid19258462>{{Cite journal | last1 = Senter | first1 = S. | last2 = Francis | first2 = GS. | title = A new, precise definition of acute myocardial infarction. | journal = Cleve Clin J Med | volume = 76 | issue = 3 | pages = 159-66 | month = Mar | year = 2009 | doi = 10.3949/ccjm.75a.08092 | PMID = 19258462 | URL = http://www.ccjm.org/content/76/3/159.full }}</ref>
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| **Usually no [[PMN]] infiltrate.
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| Classic symptoms:
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| *Retrosternal chest pain +/- with radiation down the arms.
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| *Nausea & vomiting.
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| *Diaphoresis.
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| Enzymatic tests:<ref>URL: [http://pro2services.com/Lectures/Fall/CardEnz/a6mienz.gif http://pro2services.com/Lectures/Fall/CardEnz/a6mienz.gif]. Accessed on: 27 April 2012.</ref>
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| *CK: peaks at day 1, resolves after 2-3 days.
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| *AST: peaks close to day 2, resolves after 4-5 days.
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| *LDH: peaks day 2, resolves after ~6 days.
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| Complications of MI:<ref name=Ref_PCPBoD8_293>{{Ref PCPBoD8|293}}</ref>
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| *Contractile dysfunction.
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| *[[Cardiac arrhythmia]].
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| *Aneurysm formation, e.g. left ventricular aneurysm.
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| *Ventricular rupture:
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| **Ventricular free wall rupture.
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| **Ventricular septal rupture.
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| *[[Fibrinous pericarditis]].
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| **''Dressler's syndrome'' [[AKA]] ''postmyocardial infarction syndrome''<ref name=pmid5039567>{{cite journal |author=Hutchcroft BJ |title=Dressler's syndrome |journal=Br Med J |volume=3 |issue=5817 |pages=49 |year=1972 |month=July |pmid=5039567 |pmc=1788531 |doi= |url=}}</ref>; pericarditis post-myocardial infarction +/- pericardial effusion (clinically tamponade).
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| *Mural thrombosis.
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| *Extension of MI.
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| ===Pathologic===
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| ====Gross====
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| Sequence:<ref>[http://library.med.utah.edu/WebPath/TUTORIAL/MYOCARD/MYOCARD.html http://library.med.utah.edu/WebPath/TUTORIAL/MYOCARD/MYOCARD.html]</ref>
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| *18-24 hours - myocardial pallor.
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| *1-3 days - pallor, moderate hyperemia (redness due to congestion with blood).
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| *3-7 days - yellow lesion with hyperemic border.
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| *10-21 days - maximally yellow.
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| *6 weeks - white (fibrosis).
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| ====Microscopic====
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| Sequence:<ref>[http://library.med.utah.edu/WebPath/TUTORIAL/MYOCARD/MYOCARD.html http://library.med.utah.edu/WebPath/TUTORIAL/MYOCARD/MYOCARD.html]</ref>
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| *1-3 hours - Wavy (myocardial) fibers
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| *4-12 hours - Coagulative [[necrosis]] & loss of cross striations, [[contraction band necrosis|contraction bands]], edema, hemorrhage, PMN infiltrate.
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| *18-24 hours - Coagulative necrosis, pyknosis of nuclei, and marginal contraction bands.
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| *1-3 days - Loss of nuclei (karyolysis), loss of striations, abundant PMNs.
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| *3-7 days - Macrophage and mononuclear infiltration, fibrovascular response.
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| *10-21 days - Fibrovascular response, prominent granulation tissue.
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| *6 weeks - Fibrosis.
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| Images:
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| *[http://path.upmc.edu/cases/case158/micro.html MI (upmc.edu)].
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| =====Contraction band necrosis=====
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| General:
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| *Mediated by catecholamines.<ref>{{cite journal |author=Hopster DJ, Milroy CM, Burns J, Roberts NB |title=Necropsy study of the association between sudden cardiac death, cardiac isoenzymes and contraction band necrosis |journal=J. Clin. Pathol. |volume=49 |issue=5 |pages=403–6 |year=1996 |month=May |pmid=8707956 |pmc=500481 |doi= |url=}}</ref>
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| *Thought to arise in reperfusion from hypercontraction.
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| Microscopic:
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| *Thick intensely eosinophilic staining bands (on H&E) ~ typically 4-5 micrometres wide
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| **Span the short axis of myocyte.
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| **Can be thought of bunched-up striae.
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| Notes:
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| *Better seen with special stains (Masson or Gomori trichrome).<ref>{{cite journal |author=Hopster DJ, Milroy CM, Burns J, Roberts NB |title=Necropsy study of the association between sudden cardiac death, cardiac isoenzymes and contraction band necrosis |journal=J. Clin. Pathol. |volume=49 |issue=5 |pages=403–6 |year=1996 |month=May |pmid=8707956 |pmc=500481 |doi= |url=}}</ref>
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| ======Images======
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| <gallery>
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| Image:MI_with_contraction_bands_high_mag.jpg | CBN - high mag. (WC)
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| Image:MI_with_contraction_bands_very_high_mag.jpg | CBN - very high mag. (WC)
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| </gallery>
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| ==Coronary artery atherosclerosis== | | ==Coronary artery atherosclerosis== |