Pathophysiology of Myocardial Diseases Flashcards
What are the big 3 cardiomyopathies?
Dilated (congestive)
Hypertrophic
Restrictive
Describe the appearance of the heart in Dilated cardiomyopathy
4 chamber dilitation, especially at end of diastole
Describe the appearance of the heart in Hypertrophic cardiomyopathy
Hypertrophy of ventricle, but not concentric, just bulges in certain areas
Usually hypertrophic in ventricular septum under aortic valve, causing some obstruction of aortic outflow and subaortic stenosis
Atria is enlarged
Describe the appearance of the heart in Restrictive cardiomyopathy
Ventricles appear normal, but the ventricle is not able to dilate and relax during diastole
Atria is enlarged, can see fibrosis
Which of the three cardiomyopathies has a decreased ejection fraction?
Dilated
Which of the three cardiomyopathies is systolic dysfunction?
Dilated
Cannot contract properly
Which of the three cardiomyopathies is diastolic dysfunction?
Restrictive
(and partially Hypertrophic)
Cannot fill/relax properly
Which of the three cardiomyopathies has a decreased cardiac output?
Trick! ALL 3
What are the causes of dilated cardiomyopathy?
Heterogeneous causes
- Genetic causes (30%)
- Myocarditis
- Alcoholism
- Toxins (e.g. adrimycin used for breast cancer)
- Peripartum
- End stages of hypertension can mimic this
What are the causes of hypertrophic cardiomyopathy?
Genetic (50%)
- Amyloidosis can mimic this
What are the causes of restrictive cardiomyopathy?
Amyloid in adults
Idiopathic in children
- Pericardial constriction can mimic this
Which protein is mutated in hypertrophic cardiomyopathy?
Sarcomeric proteins
What will be a major finding on echo that will indicate dilated cardiomyopathy?
Increased left ventricular end diastolic diameter (LVEDD)
What will be clinical findings of dilated cardiomyopathy?
Congestive heart failure (ineffective contraction)
Mitral and tricuspid regurgitation (due to dilation)
EF <25%
Thombi may result in strokes
If patient develops dilated cardiomyopathy from Adriamycin toxicity, what will be seen in histology?
Vacuoles in the myocytes
What will be clinical findings of hypertrophic cardiomyopathy?
Present with arrhythmias, angina, sudden death (acute onset of symptoms)
LV outflow obstruction
LA dilatation
Where will the area of abnormal hypertrophy usually be in hypertrophic cardiomyopathy?
Intraventricular septum, right below the aortic valve so it impinges on outflow
What occurs to the mitral valve in hypertrophic cardiomyopathy?
Gets thickened
Exhibits systolic anterior motion of mitral valve (SAM)
Anterior leaflet
What is the most common cause of restrictive cardiomyopathy in children?
Idiopathic
What is the most common cause of restrictive cardiomyopathy in adults?
Amyloidosis
What is the most common cause of restrictive cardiomyopathy in developing countries/tropics?
Endocardial fibrosis
How does cardiac amyloid appear macroscopically and microscopically?
Dew drop appearance macroscopically in atria
Microscopically see amyloid wrapping around the myocytes
What is the type of endomyocardial disease causing restrictive cardiomyopathy that is NOT seen only seen in the tropics?
Loffler endocarditis - hypereosinophilic disease
Eosinophils infiltrate endocardium, can cause thrombosis and scar
What type of cardiomyopathy will myocarditis cause?
Dilated
What are the 3 main types of myocarditis?
Lymphocytic (usually viral)
Hypersensitivity
Giant cell
What is the most common type of myocarditis?
Lymphocytic
What causes the damage to the myocytes in lymphocytic myocarditis?
Immune reaction to virus
What two viruses most commonly cause lymphocytic myocarditis?
Coxsackie B (enterovirus) Adenovirus
What will be seen histologically with lymphocytic myocarditis?
Myocytes necrosis
Lymphocytes everywhere
Upon survival, can exhibit fibrosis and scarring
Is lymphocytic myocarditis seen more in children or adults?
Children
Is hypersensitivity myocarditis seen more in children or adults?
Adults
What causes hypersensitivity myocarditis?
Allergic reaction to medications, especially antibiotics
What will be seen histologically with hypersensitvity myocarditis?
Eosinophils around blood vessels (not diffuse like in lymphocytic myocarditis)
Is giant cell myocarditis seen more in children or adults?
Adults
What causes giant cell myocarditis?
Thought to be immune
What will be seen histologically with giant cell myocarditis?
Macrophage giant cells clearing necrotic myocytes
See lots of lymphocytes
