CARDIOMYOPATHIES, PERICARDIAL DISEASE, AND CARDIAC TUMORS Flashcards
Explain myocarditis? etiologies?
When a diagnosis of myocarditis is made, its usage implies inflammation of the myocardium that is the primary process, not just inflammation that is present because of another process (such as a neutrophilic infiltrate with myocardial infarction NOT “myocarditis,” although technically it has an –itis of myocardium). Myocarditis characterized by a predominately lymphocytic infiltrate Given this strict definition, etiologies then revolve around infection and immune reactions. • Infectious – coxsackie A or B, HIV, CMV, Trypanosoma cruzi (Chagas disease), Borrelia burgdorferi (Lyme disease) and other less common viruses, bacteria, fungi and protozoa • Immune – SLE, post-streptococcal (RF), drug reactions, and sarcoidosis (presumed immune-mediated) Clinically, myocarditis shows a wide range of variability, and can show no symptoms to acute heart failure to fatal arrhythmias.
Explain cardiomyopathy what must be present?
Like myocarditis, this diagnosis also has more specific usage. Literally, “cardiomyopathy” means “disease process of the heart muscle” or some such. However, when a diagnosis of cardiomyopathy is made, the implication is that a few elements are present… • Mechanical (diastolic or systolic) and/or electrical (pacemaker) dysfunction of myocytes • Often (but not always) some type of overall hypertrophy or dilation to the heart silhouette • Often (but not always) an underlying genetic cause or contribution Diseases of ischemia, HTN, blood flow, thrombotic tendencies, valves, infections, congenital issues, etc. don’t ‘count’ as a cardiomyopathy because they aren’t primarily myocyte-centered
in dilated, hypertrophic, and restrictive cardiomyopathies what is the LV ejection fraction? mechanisms of heart failure? causes of phenotype? indirect myocardial dysfunction?
dilated cardiomyopathy is what? occurs when? presentation? prognosis?
DCM is predominately cardiac dilation, with a lesser component of hypertrophy, resulting in a heart silhouette that overall appears much enlarged (and indeed shows 4 chamber enlargement), yet may still appear ‘symmetrical.’
- Most common form of cardiomyopathy
- Occurs between ages of 20-50 years old
- Presentation: progressive CHF, with decreased ejection fraction (<25%), poor systolic function
- Poor prognosis; 5 year survival about 25%; may require cardiac transplantation
Causes of dilated cardiomyopathy?
- Genetics – many types of genes with many inheritance patterns and many functions (structural, mitochondrial, etc.) are identified; may cause upwards of 50% of cases
- Alcohol – and its metabolites (acetaldehyde) are directly toxic to myocytes
- Less common – pregnancy, cocaine, myocarditis viruses, drugs, iron overload
Dilated cardiomyopathy will show what pathology?
eccentric hypertrophy.
Microscopically, myocyte hypertrophy and interstitial fibrosis will be evident, with the latter occurring because of low-grade, progressive ischemia.
enlarged, globoid (rounded), and floppy gross heart
what is the difference between eccentric and concentric hypertrophy?
When myocytes are laid down in series (eccentric hypertrophy, as in an exercising heart or DCM), and accompanied by myocyte hypertrophy, growth expansion pressure is occurring in many directions causing the overall heart to appear enlarged but relatively proportional or symmetrical.
When myocytes are laid down in parallel (concentric hypertrophy, as in hypertrophic cardiomyopathy) and accompanied by myocyte hypertrophy, growth expansion pressure is mostly occurring bidirectionally causing the wall to undergo abnormal thickening without proportional expansion.
Explain hypertrophic cardiomyopathy? Clinical presentation? BOARDS NEED TO KNOW? Causes?
Somewhat in reverse to DCM, HCM has predominant hypertrophy of myocytes, causing the heart to become thick and noncompliant, leading to diastolic dysfunction.
Clinical presentations can look like anything acute or chronic, and the course is quite variable. • AKA: asymmetric septal hypertrophy or idiopathic hypertrophic subaortic stenosis, when outflow shows obstruction due to predominant septal enlargement
• Boards alert: sudden cardiac death in a young or elite athlete, leading to death during severe exercise when the cardiac outflow tract collapses, preventing blood from exiting the heart • 1 in 500 people have HCM to some degree • slightly less than half of cases are idiopathic; slight over half of cases are genetic About 50-60% of HCM is due to various genetic mutations (upwards of 400 different mutations known). Some of the more common autosomal dominant mutations are genes that code directly for β-myosin heavy chain or in proteins that stabilize/support sarcomere structure. The pathogenesis of how all these different mutations variably lead to disease is not well understood.
Explain restrictive cardiomyopathy? Causes?
Something filling the heart muscle (inter-myocyte issues) will result in noncompliance and difficulties in diastolic filling. RCM is a relatively uncommon form of cardiomyopathy, which is usually secondary then to some other problem.
- Amyloidosis – the accumulation of Congo red positive, apple green birefringent misfolded amyloid protein between myocytes
- Sarcoidosis - granulomatous inflammation with epithelioid histiocytes, giant cells, and activated CD4+ T cells in various lesions scattered throughout the heart muscle
- Metastatic tumor – scattered throughout the heart muscle, such as melanoma foci
- Loeffler endomyocarditis – endomycardial fibrosis with lots of eosinophilic infiltration and release of inflammatory components, causing injury, necrosis, and scarring
What is arrhythmogenic right ventricle cardiomyopathy? more common in? common presenting symptoms? What are also possible especially in athletes? what are important life/family issues?
This is becoming an increasingly more recognized form of an inherited cardiomyopathy. In ARVC, the right ventricle experiences progressive loss of myocytes, resulting in a thinned, somewhat dilated-appearing RV wall.
- Somewhat more common in males; can present in childhood, adolescence, or adulthood
- Syncope and dyspnea are common presenting symptoms
- Arrhythmias and sudden death are also possible (particularly among athletes)
- Curtaining of physical activity and genetic counseling are important life/family issues
what are some genes/proteins that are associated with arrhythmogenic right ventricle cardiomyopathy? What is the pattern of losing the myocytes? complications?
Many associated mutations are being identified, and prominent among them are genes encoding desmosomes (proteins), such as the intermediate filament desmin. Why the pathogenesis leads to only right ventricle myocyte loss isn’t currently known. Characteristically, the myocytes are lost from the epicardium first, and then proceed inwards toward the endocardium. Eventually fatty replacement of the RV wall becomes the predominant cell type of the right ventricle. Of course, complications will become very obvious…
- Aneurysmal dilation of the RV wall
- Conduction abnormalities (PVC’s, VT, or VF), often during exercise and possibly exacerbated by catecholamines
the pericardium and normal fluid? Increase in fluid? what are the types of fluid that can be seen?
The pericardium contains only a small amount of fluid normally (about 50mL), and like the brain, it’s in a closed cavity with relatively rigid containment (the fibrous/tough pericardial sac). Any additional fluid creates increased intra-pericardial pressure, resulting in compression of underlying heart muscle, and mechanistically, a situation that resembles a restrictive CM. Types of fluid include:
- serous fluid – serum-like fluid leading to pericardial effusion
- pus – abundant proteins, cells, and exudate, leading to a purulent/suppurative pericarditis
- blood – leading to hemopericardium
Chronic versus acute pericadial effusion? why?
Chronic pericardial fluid accumulation can get quite large (500+ mL) without evidence of underlying atrioventricular compression/diastolic filling problems.
In contrast, smaller accumulations (200 mL) of fluids that occur acutely may produce inadequate filling to meet whole body needs and physical wall collapse of the structurally weaker atria and venae cavae – the situation of fatal cardiac tamponade.
The body tolerates chronic/progressive/slow changes well, and acute/rapid changes poorly
what is pericarditis? what is serious percarditis?
Usually pericarditis is secondary to some other cardiac, thoracic, or systemic disease; primary pericarditis does occur and is often viral in etiology. Again, the type of fluid collection drives the classification of the acute process, but as an ‘-itis,’ there is usually also a prominent cellular or protein component as well. Generic types, although often mixtures of these types occur:
Serous pericarditis – non-exudative (usually non-infectious) fluid and lymphocytes, occurring secondary to mesothelial cell/serosa irritation; SLE, RA, other autoimmune diseases, neoplasms, thoracic abnormalities are underlying etiologies
What is fibrinous pericarditis? some pathology seen?
Fibrinous pericarditis – fibrin, various amounts of serous fluid and plasma proteins, and mixed inflammatory cells. The clinical presentation includes pleuritic (sharp, better sitting up, worse lying down or deep breathing) pain, fever, CHF symptoms, and a prominent pericardial friction rub.
Some settings usually show this most common type of pericarditis:
- immediately following acute MI
- a post-MI syndrome (Dressler syndrome, see below)
- uremia
- radiation to the chest
- chest trauma induced pericarditis
stringy, ragged fibrin is seen coating the heart – the so-called ‘bread and butter’ appearance typical of fibrinous pericarditis. This fibrinous process can fill the pericardial space and, over time, organize (by scar and wound healing mechanisms) into a fibrous process, causing a constrictive pericarditis, which itself can mimic a restrictive cardiomyopathy.
