January 14, 2016 - Cardiac Pathology Flashcards
Location and Extent of Infarction
Different locations will cause different tissue to infarct depending on which artery supply was cut off. Additionally, a permanent (complete) occlusion of an artery will cause a transmural (whole) section to infarct, while a partial obstruction will cause a non-transmural section to infarct. The section that infarcts is in the endocardium because it is the furthest distance away from the blood supply.
Age of the Infarct
There will be no histological changes if the infarction was less than 24 hours ago
In the acute sense between 24 hours and 2 months, you need to rely on histology for the accurate age. You will be able to see hyperemia and necrosis.
In the remote sense (>6 months), you will be able to see fibrosis.
Acute Infarction
Hyperemia and necrosis are present.
Pathologic Complications of MI
- Rupture - left ventricular free wall, septal, or papillary muscle
- Aneurysm
- Mural thrombus
- Chronic IHD
Rupture - Left Ventricular Free Wall
Not always this pronounced.
This can lead to a hemopericardium and tamponade.
Rupture - Septal
Causes shunting where blood goes from one ventricle to the other.
Rupture - Papillary Muscle
Leads to acute valvular insufficiency.
Aneurysm with Mural Thrombus
In and of itself, this isn’t that big of a deal, but this can significantly lower your ejection fraction which can lead to heart failure.
Additionally, blood pools and anytime blood pools you can get clot formation. Clot formation in the heart can lead to the clot fragments being ejected into the aorta and the rest of the body which can cause stroke, ischemic gut, ischemic kidney, or ischemic limbs.
Chronic Ischemic Heart Disease
AKA Ischemic cardiomyopathy
1. Cardiomegaly
2. Left ventricular hypertrophy
3. Obstructive coronary artery atherosclerosis
4. Patchy fibrosis, usually subendocardial
5. Myocyte hypertrophy and vacuolization
These can lead to congestive heart failure or sudden cardiac death.
Cardiomyopathy
Literally means “Disease of the Heart Muscle”
Three major categories are dilated (too big), hypertrophic (too thick), and restrictive (wall doesn’t move well).
Dilated Cardiomyopathy
One of the broad categories of cardiomyopathies.
Results in impaired contractility and therefore systolic dysfunction.
Results in a heavy, flabby heart.
Dilated ventricules can also cause valvular insufficiency.
Clinically, the patient may have heart failure, sudden death, atrial fibrillation, and stroke (if intracardiac thrombi).
Hypertrophic Cardiomyopathy
One of the broad categories of cardiomyopathies.
Impaired compliance results in diastolic dysfunction.
Massive hypertrophy without dilation.
Septum is 3x thicker than the LV free wall.
Can present with sudden death.
♦ Hypertrophic cardiomyopathy =/= Left ventricular hypertrophy due to hypertension ♦
Restrictive Cardiomyopathy
One of the broad categories of cardiomyopathies.
Impaired compliance results in diastolic dysfunction.
Usually results from amyloidosis, radiation, or idiopathy.
Normal size ventricles, but they are firm and non-compliant.
Clinically may have pulmonary hypertension and heart failure.
Myocarditis
Inflammation of the myocardium which is classified based on the type of inflammatory cell. Can see infiltrate on histology.
Lymphocytes = lymphocytic myocarditis
Neutrophils = neutrophilic myocarditis
Eosinophils = eosinophilic myocarditis
Giant cells = giant cell myocarditis
Cardiac Tumors
Cardiac myxoma is the most common cardiac tumor (over 80%).
Papillary fibroelastoma (10%).
Cardiac Myxoma
The most common cardiac tumor composing 80% of them.
Can occur at any age.
Appear gelatinous.
LA > RA
Postinflammatory Valve Disease
“Rheumatic heart disease”
Can cause mitral valve stenosis (90%) or mitral valve insufficiency (10%). Causes the mitral valve to become fibrotic and scarred with a “fish mouth” appearance.
