ICL 5.3: Clinical Cardiomyopathies Flashcards
what is a cardiomyopathy?
ventricular muscle disorders resulting in mechanical and/or electrical myocardial dysfunction
what are the main types of cardiomyopathies?
- dilated
- hypertrophic
- restrictive
other = arrhythmogenic right ventricular dysphagia and LV noncompaction
which conditions can progress into dilated cardiomyopathy?
- hypertensive HF
- ischemic HF
- valvular HF
- congenital HF
what are the types of dilated cardiomyopathy?
- idiopathic
- familial = protein mutations
- inflammatory = infectious, noninfectious, peripartum
- toxic = alcohol, chemotherapy, cocaine
- metabolic/nutritional/endocrine = thyroid dysfunction, hypocalcemia
- physiologic = tachycardia, Afib
- neuromuscular
which mutations can lead to dilated cardiomyopathy?
- cytoskeletal proteins
desmin, dystrophin, myosin-binding protein C, titin, sarcoglycans
- myofibrillar proteins
B-myosin heavy chain, troponin, alpha-tropomyosin, actin
- nuclear membrane proteins
lamin A/C
what is the pathophysiology of dilated cardiomyopathy?
myocyte injury —> decreased contractility and SV –> LV dilation and mitral regurgitation because LV starts to dilate and the annulus gets stretched out
then decrease in forward flow leads to fatigue and weakness
increased ventricular filling pressures due to decreased contractility leads to pulmonary congestion (dyspnea, orthopnea, rales) and systemic congestion (JVD hepatomegaly, edema)
what are the signs and symptoms of dilated cardiomyopathy?
- slow progressive onset = weeks to months
- congestion is the main problem = DOE and edema
- lungs = basilar chest dullness due to pleural effusions – cracker
- cardiomegaly
- S3
- mitral regurgitation
what are the venous congestion signs seen in dilated cardiomyopathy?
- JVD
- hepatomegaly
- ascites
- peripheral edema
- RV enlargement due to fluid overload/preload increase
- tricuspid regurgitation due to RV enlargement
what is noninfectious dilated cardiomyopathy?
this is peripartum dilated cardiomyopathy! so it has to present itself in the last month of pregnancy and up to 6 months post-birth
50% recover
what are the risk factors for noninfectious dilated cardiomyopathy?
- older women,
- african american
- multiple pregnancies put you at risk for it
how do you treat noninfectious dilated cardiomyopathy?
if they develop it during pregnancy, avoid nonselective BB like carvedilol; use B1 selective BB – no ACEI because teratogenic –> use hydralazine/nitrate combination to decrease afterload (both are arterial dilators and nitrates also dilate venous)
if the LV EF <25% or if LV dusfunction persists more than 6 months, subsequent pregnancies are not recommended due to SCD
also anticoagulation is recommended because the stasis causes increased risk for thrombus
what is stress cardiomyopathy?
apical ballooning syndrome aka broken heart syndrome
it’s a transient regional systolic dysfunction of LV apex with sparing of the base – the heart looks like a balloon
it present like an acute mI with ST elevation that doesn’t follow a certain coronary artery pattern and therefore the cardiac cath test will show normal coronary arteries
what is the etiology of stress cardiomyopathy?
females > males
postmenopausal women more common
usually you can identify the stress by taking a good history = loss of partners, job, bad news, emotional trigger
what is the pathophysiology of stress cardiomyopathy?
we really don’t now how it happens…
we know there are excess catecholamines and microvascular disease but that’s it (NOT classic epicardial CAD)
what lab results are seen with stress cardiomyopathy? EKG?
EKG abnormal = ST elevation, WT prolongation
troponin (+) and BNP (+)
how do you treat stress cardiomyopathy?
treat like HF with B-blockers, ACI, ARBs, diuretics
excellent prognosis; normally recover in months but recurrences are possible
what is restrictive cardiomyopathy?
RCM has impaired diastole due to loss of compliance from fibrosis of endomyocardial tissue or from infiltration of a noncontractil complex/material into the myocardium
compliance is volume expansion in response to increased pressure and this is lost in RCM
there is a normal EF though until end stage because the cells that can contract will contract till the very end but you just can’t relax as well
what are the classes of restrictive cardiomyopathy?
- noninfiltrative –> idiopathic, scleroderma
- infiltrative –> amyloidosis, sarcoidosis
- storage diseases –> hemochromatosis, glycogen storage diseases
- endomyocardial disease (fibrosis) –> metastatic tumors, radiation therapy, hypereosinophilic syndrome
why is there reduced LV filling and CO but the EF is normal?
EF = SV/EDV
SV and EDV both decrease
the CO is an absolutely number while the EF is a ratio so that’s why it doesn’t change even though the CO decreases
what are symptoms of restrictive cardiomyopathy?
- fatigue
- weakness
- DOE
- venous congestion
- usually HF signs and symptoms
- horrible exercise intolerance because they can’t get the volume of filling that they need and it only gets worse with exercise
what is the pathophysiology of restrictive cardiomyopathy?
rigid myocardium causes increased diastolic pressures which lead to increased systemic and pulmonary venous pressures which can cause R and L HF = JVD, hepatomegaly, ascites, edema
the rigidity means that there’s less ventricular filling and dilation because it can’t expand so you have decreased CO and compensatory increase in HR = fatigue and weakness
what are the PE findings seen with restrictive cardiomyopathy?
- tachycardia
- JVD
- Kussmaul sign
- pulmonary congestion with rales
- Afib
- tricuspid murmur
- ascites
- peripheral edema
what is Kussmaul sign?
an paradoxical increase in jugular venous pressure with inspiration that happens because the RV is also stiff and can’t accommodate higher volumes caused by LV stiffness
seen in restrictive cardiomyopathy
what are the diagnostic tests done for restrictive cardiomyopathy?
- EKG
2. echo
what are the EKG findings for restrictive cardiomyopathy?
- usually nonspecific ST and T wave changes (can be Afib rhythm)
- amyloid heart: low voltage and Q waves
3, sarcoid: conduction blocks
what are the echo findings for restrictive cardiomyopathy?
- dilated atria
- LV normal/small chamber size from stiffness
- LV EF is normal until end stage
you can identify amyloid in the heart by echo based on the strain pattern and it’ll look like LV hypertrophy but NOT based on ECG because amyloid is a noncontractive protein and won’t effect contraction
what is constrictive pericarditis?
sac around the heart won’t let the heart expand enough
muscle isn’t able to expand so it has really similar presentation to restrictive cardiomyopathy
how can you differentiate restrictive cardiomyopathy and constrictive pericarditis?
- echocardiogram
- invasive heart catheterization (hemodynamic study)
- CT chest or MRI (thick pericardium in constrictive pericarditis)
- EM Biopsy can be helpful too (normal in constrictive pericarditis)
how do you treat restrictive cardiomyopathies?
we don’t have much to treat this….overlal poor prognosis
symptom relief with medications like diuretics
if it’s caused by hemochromatosis you can do iron chelation
if it’s caused by primary amyloid which means it’s caused by amyloid light chain you can do chemo plus stem cell transplant
if it’s secondary amyloid that means it’s a mutation of the TTR amyloid that can infiltrate the heart and you can treat with new drugs that prevent accumulation of TTR protein
what is arrhythmogenic right ventricular dysplasia?
the RV gets a fatty infiltration that causes it to dilate so that it’s not able to contract –> replacement of mainly RV free wall by fibrofatty tissues but no idea why
it’s a genetic disorder that’s AD or AR with incomplete penetrance = the presentation is incomplete and not everyone that has AD form will have the phenotype
it’s the gene that codes for desmosomes!!! specifically plakoglobin and demsoplakin that lead to a loss of intercalated discs because the fatty infiltrate gets between the cells and spreads them apart
what are the test results that point to arrhythmogenic right ventricular dysplasia?
- EKG shows an epsilon wave; this is basically pathopneumonic for ARVC!!
- dilated RV on echo but MRI is way more useful
- cardiac biopsy but not great because lots of false positive
- genetic testing when a family member is diagnosed
- RV arrhythmias
what are the effects of arrhythmogenic right ventricular dysplasia on the heart?
the fatty infiltrates mess up the gap junctions which are important for electrical conduction so this lead to palpitations, syncope and SCD!!
the only treatment is an ICD for prevention of SCD
what is left ventricular noncompaction?
the LV is not compacted; there are trebeculi literally everywhere so you get deep recesses
this is due to a sarcomere mutation!
they cause contraction and relaxation abnormalities which lead to HF and conduction abnormalities that lead to arrhythmias
there’s also a thrombotic risk because of all the stasis happening in all the crevices
what is the genetic inheritance of left ventricular noncompaction?
AD, AR or x-linked
how do you treat left ventricular noncompaction?
- anticoagulation
- ICD
- transplant
what changes happen to the sarcomere in volume vs. pressure overload?
volume overload = sarcomeres added in series = eccentric LV hypertrophy
ex. aortic or mitral regurgitation, ischemic heart disease, dilated cardiomyopathy
pressure overload = sarcomeres added in parallel = concentric LV hypertrophy
ex. chronic hypertension or aortic stenosis
