Cardiomyopathies, Myocarditis, Pericarditis, Tumors, and Transplant Flashcards
What is a primary cardiomyopathy?
diseases of the heart muscle typically confined to myocardium
What is a secondary cardiomyopathy?
systemic cause of the cardiomyopathy (e.g. hemochromatosis)
What are the three types of cardiomyopathy?
- dilated (congestive)
- hypertrophic (most common form)
- restrictive (some kind of infiltrate in the myocardial muscle or pericardium prevents normal beating of the heart)
Which chambers are dilated in dilated cardiomyopathy?
all of them
What is the most common cause for dilated cardiomyopathy?
chronic alcoholism
Other causes of dilated cardiomyopathy?
- some may be the end-stage of remote viral myocarditis caused by coxsackievirus V and other enteroviruses)
- dystrophin gene mutations
What meds could cause dilated cardiomyopathy?
doxorubicin
Describe the gross appearance of a heart with dilated cardiomyopathy?
flabby, all chambers dilated, wall thinning accompanies the dilation
ventricular thickness varies
What are some potential consequences of dilated cardiomyopathy?
- mural thrombi due to stasis near the margins of the dilated chambers, leading to emboli
- valvular regurgitation
What is Beriberi heart disease?
chronic alcoholism is associated with thiamine deficiency (vitamin B1) historically present in places where polished rice were a large part of the diet
What are the two major types of beriberi?
- Wet beriberi
- Dry beriberi and Wenicke-Korsakoff syndrome
What does wet beriberi affect?
CV system causing congestive heart failure
What does dry beriberi affect?
nervous system causing neurologic and/or psychiatric symptoms
What does hypertrophic cardiomyopathy cause?
- diastolic dysfunction (impaired contractility)
- can result in idiopathic hypertrophic sub aortic stenosis (IHSS)
What causes idiopathic hypertrophic sub aortic stenosis (IHSS)?
asymmetric interventricular septal hypertrophy that pushes into the left ventricle and can close off the aortic valve
How does hypertrophic cardiomyopathy look grossly?
interventicular septum comrpesses ascending aorta and the left atrium is usually enlarged
How does hypertrophic cardiomyopathy look microscopically?
cardiac fibers are in disarray and run in many directions and become surrounded by collagen
So what do you see in hypertrophic cardiomyopathy?
- marked left ventricular hypertrophy
- asymmetric bulging of a very large inter ventricular septum into the left ventricular chamber
- reduced SV and impaired diastolic filling and overall smaller chamber size
- deceased left ventricular compliance
The abnormal areas caused by hypertrophic cardiomyopathy can lead to what?
arrhythmias
Many (most) cases of hypertrophic cardiomyopathy are caused by what?
mutations in genes encoding for sarcomeric proteins (B-myosin heavy chain)
What do defects in B-myosin heavy chains cause?
defects in energy transfer from mitochondria to sarcomeres and/or direct sarcomere dysfunction
What are some causes of restrictive cardiomyopathy?
anything that infiltrates the pericardium and impairs ventricular filling (diastolic) such as amyloidosis, hemochromatosis, or radiation-induced fibrosis
How does restrictive cardiomyopathy present?
- ventricles are normal size
- cavities are not dilated
- myocardium is firm
- bi-atrial dilation is common due to decreased ability of ventricles to fill
What are some problems associated with hemochromatosis?
- liver cirrhosis
- pancreas dysfunction
- arryhthmias and HF
- reproductive problems
- skin color change (bronzing)
How does hemochromatosis affect the heart specifically?
decreased ventricular compliance with impaired ventricular filling during diastole because of iron deposits
someone with a genetic hemochromatosis that impairs heart function is considered a restrictive caridomyopathy
What is iron overload cardiomyopathy?
decreased as dilate cardiomyopathy characterized by left ventricular (LV) remodeling with chamber dilation and reduced LV ejection fraction
What is myocarditis?
infectious agents and/or inflammatory processes targeting the myocardium.
Mostly caused by viruses (so see more lymphocyte reaction than neutrophil infiltrate) but can be caused by bacteria
Coxsachievrisus A and B and other enteroviruses most common
How does the heart appear grossly in myocarditis?
- normal or slightly dilated
- flabby, pale colored
- mural thrombi may be present
How does the heart appear microscopically in myocarditis?
- edema
- interstitial inflammatory infiltrates prominent
- myocyte injury common
- viral/bacterial abscesses can occur
What bug causes Chagas disease?
Reduviid bug (trypanosoma cruzi-protazoan)
Chagas disease commonly affects what patient population?
patients in central/South America that live in houses with thatched roofs, where Trypanosoma cruzi typically live
What occurs in Chagas disease?
bug bite causes parasite deposit into the blood rbcs (typically diagnosed in the blood) that can lead to death and deposit into scattered myofibers and are then accompanied by inflammatory infiltrate of neutrophils, lymphocytes, macrophages, and some eosinophils leading to fibrosis and potentially thrombosis formation
What does Toxoplasma gondii cause?
it is an obligate intracellular, parasitic protozoan common in cat feces that typically affect immunocompromised people and cause tissue pseudocyst in myocardial cells
Toxoplasma gondii infection is especially associated with what?
heart transplant (immunocompromised)- usually a reactivation
pregnancy- primary infection
What causes Lyme Disease?
a gram negative spirochete called Borrelia burgdorferi
What are some common carriers of borrelia burgdorferi?
-Ixodes scapualris (the black-legged tick) and in the western states, I. pacific us (the western black-legged tick)
How long does an Ixodes tick have to be on you to transmit borrelia burgdorferi?
at least 24hrs
What are some non-infectious causes of myocarditis?
- immune mediated-i.e. SLE
- Hypersensitivity/Drug induced
- giant cell myocarditis
T or F. Drug hypersensitivity reactions can occur via a wide range such agents and are typically benign
T, only in rare circumstances do these lead to CHF or sudden death
On the other hand, giant cell myocarditis carrier a poor prognosis
What are some causes of secondary pericarditis?
- uremia
- rheumatic fever
- SLE
- metastasis
What is uremia?
a clinical syndrome associated with fluid, electrolyte, and hormone imbalances and metabolic abnormalities, which develop in parallel with deterioration of renal function
What are the potential outcomes of pericarditis?
- typically resolve without significant sequelae
- can progress to a chronic fibrosing process or cardiac tamponade
What are some types/causes of pericardial effusion?
- serous
- serosanguineous
- chylous
What things commonly cause serous pericardial effusion?
CHF
hypoalbuminemia of any cause
What things commonly cause serosanguineous pericardial effusion?
blunt chest trauma
malignancy
ruptured MI or aortic dissection
What things commonly cause chylous pericardial effusion?
mediastinal lymphatic obstruction
What is the most common tumor of the heart?
metastasis of some kind from another primary - may present as effusion
What are some common cancers that metastasize to the heart?
- pleural mesothelioma (48.4%)
- melanoma (27.8%)-multiple lesions
- lung adenocarcinoma
- lung squamous cell carcinoma
- breast carcinoma
Hodgkins and urothelial carcinoma
What paths can tumor use to spread to the heart?
- direct extension
- bloodstream
- lymphatic
- intracavitary diffusion through either the IVC or the pulmonary veins
What are myxomas?
most common primary heart tumors (about 80% in left atrium)
Note about myxomas
They are pedunculate so they often are mobile enough to swing into the mitral or tricuspid valve during systole, causing intermittent obstruction or exerting a ‘wrecking ball’ effect that damages the valve leaflets
What is another type of primary heart tumor?
rhabdomyoma
Describe rhabdomyomas.
Primary heart tumors found most in ventricles in infants and children that can spontaneously regress
What are rhabdomyomas commonly associated with?
tuberous sclerosis caused by mutations in the TSC1 or TSC2 tumor suppressor genes leading to myocyte overgrowth
What are the two major type of cardiac transplant rejection?
- acute cardiac rejection
- allograft arteriopathy
What are heart transplant patients particularly at risk for?
immunosupression increases risk of opportunistic infections and certain post-transplant lymphoproliferative disease (PTLD)
PLTD is most associated with what?
EBV
How do we check for rejection?
several endomyocardial biopsies are taken
What is rejection characterized by?
intersitial lymphocytic inflammation associated with myocyte damage (similar to viral myocarditis)
