Difference between revisions of "Heart"

Jump to navigation Jump to search
4,468 bytes removed ,  01:56, 8 January 2014
Line 281: Line 281:
*Abbreviated ''MI''.
*Abbreviated ''MI''.
*[[AKA]] ''myocardial infarct''.
*[[AKA]] ''myocardial infarct''.
===Clinical===
{{Myocardial infarction}}
*Usually diagnosed clinically - with blood work (troponin, CK-MB) or EKG.
*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>
*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>
**Usually no [[PMN]] infiltrate.
 
Classic symptoms:
*Retrosternal chest pain +/- with radiation down the arms.
*Nausea & vomiting.
*Diaphoresis.
 
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>
*CK: peaks at day 1, resolves after 2-3 days.
*AST: peaks close to day 2, resolves after 4-5 days.
*LDH: peaks day 2, resolves after ~6 days.
 
Complications of MI:<ref name=Ref_PCPBoD8_293>{{Ref PCPBoD8|293}}</ref>
*Contractile dysfunction.
*[[Cardiac arrhythmia]].
*Aneurysm formation, e.g. left ventricular aneurysm.
*Ventricular rupture:
**Ventricular free wall rupture.
**Ventricular septal rupture.
*[[Fibrinous pericarditis]].
**''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).
*Mural thrombosis.
*Extension of MI.
 
===Pathologic===
====Gross====
Sequence:<ref>[http://library.med.utah.edu/WebPath/TUTORIAL/MYOCARD/MYOCARD.html http://library.med.utah.edu/WebPath/TUTORIAL/MYOCARD/MYOCARD.html]</ref>
*18-24 hours - myocardial pallor.
*1-3 days - pallor, moderate hyperemia (redness due to congestion with blood).
*3-7 days - yellow lesion with hyperemic border.
*10-21 days - maximally yellow.
*6 weeks - white (fibrosis).
 
====Microscopic====
Sequence:<ref>[http://library.med.utah.edu/WebPath/TUTORIAL/MYOCARD/MYOCARD.html http://library.med.utah.edu/WebPath/TUTORIAL/MYOCARD/MYOCARD.html]</ref>
*1-3 hours - Wavy (myocardial) fibers
*4-12 hours - Coagulative [[necrosis]] & loss of cross striations, [[contraction band necrosis|contraction bands]], edema, hemorrhage, PMN infiltrate.
*18-24 hours - Coagulative necrosis, pyknosis of nuclei, and marginal contraction bands.
*1-3 days - Loss of nuclei (karyolysis), loss of striations, abundant PMNs.
*3-7 days - Macrophage and mononuclear infiltration, fibrovascular response.
*10-21 days - Fibrovascular response, prominent granulation tissue.
*6 weeks - Fibrosis.
 
Images:
*[http://path.upmc.edu/cases/case158/micro.html MI (upmc.edu)].
 
=====Contraction band necrosis=====
General:
*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>
*Thought to arise in reperfusion from hypercontraction.
 
Microscopic:
*Thick intensely eosinophilic staining bands (on H&E) ~ typically 4-5 micrometres wide
**Span the short axis of myocyte.
**Can be thought of bunched-up striae.
 
Notes:
*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>
 
======Images======
<gallery>
Image:MI_with_contraction_bands_high_mag.jpg | CBN - high mag. (WC)
Image:MI_with_contraction_bands_very_high_mag.jpg | CBN - very high mag. (WC)
</gallery>


==Coronary artery atherosclerosis==
==Coronary artery atherosclerosis==
48,830

edits

Navigation menu