Gross, Histological, and Clinical Findings of MI

Question 1

What are the apparent gross findings 1.4-4hrs after MI?

Answer 1

none

Question 2

Describe the histopathology 1.4-4hrs after MI?

Answer 2

None or wavy fibers. Wavy fibers as early as 1-3 hours.

Contraction bands, when present, can occur early (as early as after 2 minutes of reperfusion in animal experiments).

Question 3

What are the clinical correlations 1.4-4hrs after MI?

Answer 3

Mural thrombi can form early and embolize at any time

Question 4

What are the apparent gross findings 4-12hrs after MI?

Answer 4

pecial staining shows lack of dehydrogenase as early as 2-3 hours.

Question 5

Describe the histopathology 4-12hrs after MI?

Answer 5

Early coagulation necrosis, edema, hemorrhage, Earliest sign is hypereosinophilia of myocytes.

Question 6

What are the clinical correlations 4-12hrs after MI?

Answer 6

CK and CK-MB elevated 4-48 hours. Troponin I

8-72 hours.

Question 7

What are the apparent gross findings 12-24hrs after MI?

Answer 7

Pallor or red-blue hue (dark mottling). Occasionally, hemorrhage, especially when thrombolysis was administered.

Question 8

Describe the histopathology 12-24hrs after MI?

Answer 8

Coagulation necrosis, hypereosinophilia, pyknosis as early as 5 hours, loss of striations later, contraction band necrosis, polys as early as 6-8 hours

Question 9

What are the clinical correlations 12-24hrs after MI?

Answer 9

Serious arrhythmias can occur at any time due to neutrophils coming in. Primary ventricular fibrillation – usually in 1st12 hours.

death common in this time period

Question 10

Describe the histopathology 1-3days after MI?

Answer 10

Coagulation necrosis, loss of nuclei 24-48 hours, more loss of striations, polys peak at 48 hours

Question 11

What are the clinical correlations 1-3days after MI?

Answer 11

Neutrophils expand and cause pericarditis leading to pericardial friction rub, due to fibrinous pericarditis, most common on days 2-3

Question 12

What are the apparent gross findings 3-7days after MI?

Answer 12

As macrophages and necrotic tissue predominate, tissue is soft and appears yellow/tan with red border due to hyperemia. Prone to rupture.

Question 13

Describe the histopathology 3-7days after MI?

Answer 13

Early disintegration of dead muscle, dying polys.

Macrophages appearing and increasing- time of instability and rupture of the wall is possible here

Question 14

What are the clinical correlations 3-7days after MI?

Answer 14

Rupture of free wall (resulting in cardiac tamponade), ventricular septum, or papillary muscle at 3-6 days

Question 15

Describe the histopathology 7-10days after MI?

Answer 15

Macros with phagocytosis, early granulation tissue. Proliferation of blood vessels as early as 3 days.

Fibroblasts present as early as 4 days

Question 16

Describe the histopathology 10-14days after MI?

Answer 16

Granulation tissue recognized as early as 7-10 days. Collagen fibers as early as 9 days.

gross appearance of heart is red-grey

Question 17

What are the clinical correlations 10-14days after MI?

Answer 17

Dressler syndrome, an autoimmune-based pericarditis, at 1-8 weeks

Question 18

What are the apparent gross findings 2-8weeks after MI?

Answer 18

Appearance evolves to that of a white, fibrous scar.

Question 19

Describe the histopathology 2-8weeks after MI?

Answer 19

Increased collagen and decreased cellularity. Peak granulation tissue at 2-4 weeks. Dense scar (type 1 collagen) as early as 6 weeks.

Question 20

What are the clinical correlations 2-8weeks after MI?

Answer 20

Ventricular aneurysms are a late complication.