A number of gross and microscopic findings may appear, develop and then resolve after a myocardial infarction. These findings can help approximately date when a myocardial infarct occurred.
|
Days After AMI |
Gross Myocardial Color |
Myocardial Consistency |
Other Features |
|
0.5 (12 hours) |
normal |
normal |
|
|
1-2 (24 - 48 hours) |
pale red |
soft |
|
|
3 days |
yellow, pale red |
soft |
raised |
|
4-7 days |
yellow |
soft, risk of rupture |
demarcating rim, raised |
|
7-8 days |
yellow green |
soft |
raised |
|
8-14 days |
yellow to red |
soft |
|
|
21-30 (3-4 weeks) |
red |
soft |
depressed |
|
30-60 (1-2 months) |
red to gray |
rubbery |
|
|
60-90 (2-3 months) |
grey |
firm |
contracted |
|
>= 120 days |
white |
firm |
|
|
Histologic Feature |
Appear |
Reach Maximum |
Gone |
|
necrosis |
1 (24 hours) |
3-6 days |
100 days |
|
neutrophils |
0.5-1 (12-24 hours) |
4-5 days |
21 days |
|
pigmented macrophages |
6 days |
21-28 days |
> 365 |
|
eosinophils |
6 days |
14 days |
21 days |
|
lymphocytes |
6 days |
21-28 days |
> 100 days |
|
collagen |
14 days |
84-120 days |
> 365 |
where:
• Collagen can be evaluated on special stains (trichrome, other) or under polarized light.
|
PMNs |
Necrosis |
Other Cells |
Collagen |
Time |
|
none |
none |
none |
none |
< 12 hours |
|
few |
early |
none |
none |
12-24 hours |
|
heavy |
present |
none |
none |
1-5 days |
|
present |
present |
eosinophils, lymphocytes, monocytes |
none |
6 - 14 days |
|
few |
present |
eosinophils, lymphocytes, macrophages |
present |
14-21 days |
|
absent |
present |
lymphocytes, macrophages |
present |
> 21 days |
Cases which may pose problems for identification:
(1) small infarcts
(2) acute infarction superimposed on a chronic infarct
Specialty: Cardiology
ICD-10: ,
