Wk5: Witrak Flashcards
Leading cause of M&M in developed world with 95% due to what
Ischemic heart disease; coronary atherosclerosis
What defines an unstable atherosclerotic plaque?
risk of rupture with partial or complete lumen occlusion by aggregated platelets/thrombosis
What is acute coronary syndrome?
Coronary blood supply is suddenly blocked - either unstable angina or MI
How many minutes of complete ischemia -> myocardial death
30 minutes +
EKG changes with subendocardial and transmural infarctions
Sub: usually non-STEMI
Transmural: more likely STEMI (older -> Q waves)
Subacute sequelae of MI (days to 2 weeks)
Mural thrombosis, LV rupture (free wall, septal, or papillary muscles), fatal hemopericardium, acute VSD, mitral regurg/flail, peri-infarct pericarditis
Chronic sequelae of MI
LV aneurysm, chronic CHF, pleural effusions, 2* RV CHF, Dressler’s pericarditis
What is another name for Dressler’s pericarditis, and what is it?
Post-cardiac injury syndrome. Believed to be an immune response to damaged tissue after MI, trauma, surgery to pericardium or heart.
How does stable chronic atherosclerotic disease present a risk of sudden death?
Sudden/fatal vent dysrhythmia from ischemic aggravation to the conduction system
What causes left-sided hypertensive heart disease? What happens?
Chronic systemic (arterial) htn -> concentric LV hypertrophy (free wall >1.5 cm) -> LV failure
Isolated Right Sided hypertensive heart disease (cor pulmonale) cause
Inc pulm artery pressure from: 1)chronic pulm parenchymal disease e.g. COPD, fibrosing 2)chronic hypoxia e.g. sleep apnea -> pulm vasoconstriction 3)pulm vasc disease e.g. 1* pulm htn and chronic recurrent thromboemboli
Size of RV free wall in RV hypertrophy
Free wall >0.5 cm.
Cause of most RV HF
LV HF
Possible causes of aortic valve regurg
Thoracic aortic aneurysm -> valves can’t close properly. Aortic dissection.
Causes of AV valve insufficiency
CHF -> valve ring dilation, papillary muscle dysfunction from LV ischemia with CAD
Define cardiomyopathy
Intrinsic myocardial disease NOT assoc w ischemic, valvular, hypertensive, or structural congen heart disease
What type of cardiomyopathy is essentially 100% genetic/mutational cause
Hypertrophic
What is cardiac tamponade?
Pericardial fluid critically compresses the heart
What is constrictive pericarditis?
progressive pericardial space fibrosis (like a growing scar) -> compression of heart
Causes of pericardial effusion
infectious and non-infectious disease, CHF, neoplastic infiltration, uremia
Most primary tumors of the heart are what type?
Atrial myxomas, very rare, usually left atrium
Other primary cardiac tumors
Rhabdomyomas - children esp tuberous sclerosis (gene defect -> growth of benign tumors). Cardiac sarcomas: very rare, usually lethal.
Are myocytes or the pericardium more likely to be sites of metastases?
Pericardium
What O2 sat defines cyanosis
<85%
How long does it take a troponin to become positive in AMI? When does it peak, and how long does it persist?
2-4 hours to be positive. Peaks ~48 hours. Persists 7-10 days.
How does CK-MB compare to troponin?
Also elevated with myocardial necrosis but less specific than trop. Does drop down sooner allowing for detection of a second event.
What causes release of BNP? What are significant lab values?
Stretch of myocardium esp LV. 400 HF more likely cause of dyspnea
Main cause of hypercarbia
(inc pCO2 @ >45 mmHg): alveolar hypoventilation, usually due to COPD
When can O2 saturation be normal yet the patient is hypoxemic?
CO poisoning
AMI mortality within one month
30%
How might you get a circumferential LV subendocardial infarct?
Global hypotension
What is the immune response to death of cardiac myocytes?
Neutrophils within a couple days, fibroblasts in 1.5-3 weeks, collagen scar formation in 4-6 weeks.
Possible causes of CHF post infarct
1) Perforation of septum -> VSD -> acute CHF. 2) decreased functioning of myocardium due to necrotic regions -> CHF 3) transmural -> scarring -> loss of compliance -> akinetic -> CHF
Define systolic and diastolic HF
Systolic: low EF. Diastolic: preserved EF but decreased compliance -> can’t relax -> can’t fill appropriately and backs up blood -> pulmonary sx
How might diastolic failure lead to a-fib?
Associated atrial enlargement -> a-fib
Can LVH be reversed?
Yes, fairly quickly with control of hypertension
What does the LV look like in congenital LVH?
Thickening of septum moreso than the free wall.
Define cor pulmonarle
Right-sided hypertensive heart disease due to chronic hypoxemic pulm disease (e.g. COPD) or pulm htn
Causes of valvular stenosis
Valvulitis (RF, SLE, RA), congen deform, CALCIFIC degen change, carcinoid syndrome, radiation
Commonest cause of mitral stenosis
Rheumatic fever
2/3 of clinically significant valve disease = acquired aortic or mitral stenosis. Causes?
1) gradual obstruction due to post inflam fibrosis/deform (RF, SLE, RA) 2)atherosclerotic or calcific degen (esp AS)
What is ankylosing spondylitis?
Inflammatory disease -> fusing of vertebrae
How are valvular diseases diagnosed?
echo
What is myxomatous degeneration?
Pathological weakening of connective tissues
Most common cause of isolated mitral regurg in N Amer requiring surgery
Myxomatous degeneration -> ballooning of valve leaflets and elongation of chordae tendinae
What is “fish mouth” associated with?
A valve with typical rheumatic fever damage
Other than IE, what may result in vegetations on heart valves?
hypercoagulable state due to malignancy
What is systolic click murmur syndrome?
Mitral valve prolapse
What is dilated CM?
Dilated ventricles -> systolic LV dysfunction with decreased LVEF
What is hypertrophic CM?
Thickened LV wall esp septum with normal to reduced LV chamber size -> diastolic LV dysfunction
What is restrictive CM? What causes it?
Diastolic LV dysfunction assoc with usually non-dilated, usually non-hypertrophic ventricles due to primary dec in vent compliance.
Dilation of atrium = risk for ?
Clot formation
Dilated CM associated with what
Increased cardiac mass, HF symptoms e.g. dyspnea and fatigue, atrial of ventricular arrhythmias, possible sudden death
Causes of dilated CM (6)
Genetic 20-50%, myocarditis, alc abuse, chemo e.g. doxorubicin, hemochromatosis, peripartum, idiopathic
Dilated CM age of onset and mortality
Commonly 20-50 y.o. and leading to 50% mortality within 2 years.
Treatment for dilated CM
Supportive HF measures, possibly a LVAD (for myocardial recovery or bridge to transplant)
Commonest cause of hypertrophic CM (specific)
Autosomal dominant defect in sarcomeric contractile proteins (60–70%)
How does the ventricle appear in hypertrophic CM (specifically)
Asymmetrically thickened septum, especially in subaortic/basal region
What component of functioning is impaired in hypertrophic CM?
Diastolic relaxation/ filling -> limited CO -> inc LVEDP. May have syst murmur due to blood trying to pass by fat septum
Top 3 causes of sudden death in young athletes
- hypertrophic CM 2. anomalous coronary artery origin 3. myocarditis
Symptoms of HCM
DOE, myocardial ischemia without CAD, risk of a-fib, eventual vent. failure/dilation, vent arrhythmias, sudden death
How does LVH appear when due to inc BP or aortic stenosis
Usually concentric thickening
Treatment for hypertrophic CM
Beta blockers, occasionally partial septal ablation
How does restrictive CM present?
Manifests as right HF. Systolic fx usually normal early.
A few causes of RCM
Familial, amyoidosis, diabetic CM, sarcoidosis, chemo (esp anthracyclines), metabolite deposition from inborn errors of metab, radiation fibrosis
What is arrhythmogenic RV CM? What causes it?
Autosomal dominant. Markedly thinned RV wall with fibroadipose tissue -> conduction disturb -> RV failure
What disease is arrhythmogenic RV CM associated with?
palmar/plantar hyperkeratosis. The combo = Naxos syndrome
Mechanism of stress-induced CM
Catecholamine surge -> “myocardial stunning” with transient systolic dys
How does stress-induced CM present
ischemic heart sx, foci of myocardial necrosis
Other causes of CM
Pheochromocytoma (adrenal tumor), cocaine use
Clinical sequelae of hemochromatosis
CM/HF (usually dilated type), conduction disturbance, cirrhosis/hepatoma, endocrine dys, arthritis
What effect does excess hemosiderin have on myocytes?
Toxicity -> secondary fibrosis
How is hemochromatosis diagnosed
> 45% transferrin saturation, HFE gene mut, hepatic iron index noted on liver biopsy
What occurs in amyloidosis?
deposition of amorphous proteinaceous substance that is congo red positive
Sequelae of cardiac amyloidosis
usually restrictive CM -> HF, low EKG voltage, increased vent thickness, non-dilated LV cavity
Most common causes of myocarditis in US
Viral: entero, coxsackie B, adenovirus, parvo B19, hep C, HHV-6, CMV, HIV
Cause of myocarditis in developing/ endemic latin American countries
Chagas: attacks heart and esophagus -> HF + dysphagia
Acute HF within weeks of viral prodrome, possibly with CP, arrhythmia, sudden death = classic presentation of ?
Myocarditis
Most common cause of HF in children
myocarditis
