Cardiomyopathies Flashcards
(50 cards)
What is the most common cardiomyopathy? What is the least common?
Most = Dilated Cardiomyopathy
Least = Restrictive cardiomyopathy
Describe Dilated cardiomyopathy. What is the ejection fraction? Mechanism of heart failure? Causes of phenotype? Indirect myocardial dysfunction (mimicking cardiomyopathy)?
EF < 40%
Mechanism = impairment of contractility (systolic dysfunction)
Causes of phenotype: genetic, alcohol, hemochromatosis, etc.
Mimicking = IHD, VHD, HHD, congenital HD
Describe Hypertrophic cardiomyopathy. What is the ejection fraction? Mechanism of heart failure? Causes of phenotype? Indirect myocardial dysfunction (mimicking cardiomyopathy)?
EF = 50-80%
Mechanism = Impairment of compliance (diastolic dysfunction)
Causes of phenotype: genetic, infants of diabetics, storage DO
Mimicking = HHD, aortic stenosis
Describe Restrictive cardiomyopathy. What is the ejection fraction? Mechanism of heart failure? Causes of phenotype? Indirect myocardial dysfunction (mimicking cardiomyopathy)?
EF = 45-90%
Mechanism = Impairment of compliance (diastolic dys)
Causes of phenotype: Amyloidosis, radiation induced fibrosis, idiopathic
Mimicking = pericardial constriction
What is Dilated cardiomyopathy (DCM)?
Progressive cardiac dilation and systolic dysfunction, usually with dilated hypertrophy
What is the genetic basis behind DCM?
Thought to be familial in 30-50% of cases
TTN mutations may account for 20% of all cases
Usually autosomal dominant
What cause is strongly linked to DCM? What else is related?
Alcohol
Myocarditis
Cardiotoxic drugs/substances = doxorubicin, cobalt, iron overload
Why does iron overload occur leading to DCM?
Iron overload from hereditary hemochromatosis (HFE mutation) or multiple transfusions
Use the prussian blue iron stain
What is the morphology of dilated cardiomyopathy?
Dilation of all chambers
Mural thrombi
Functional regurgitation of valves
What is the presentation of DCM?
Usually manifests b/w ages 20-50 yo
Progressive CHF –> dyspnea, exertional fatigue, decreased EF
Arrhythmias (sudden death)
Embolism
What is Takotsubo cardiomyopathy?
A dilated cardiomyopathy
“Broken heart syndrome”
Excess catecholamines following extreme emotional or psychological stress
How does takotsubo cardiomyopathy present?
> 90% in women
Ages 58-75
Sx and sign similar to acute MI
Apical ballooning of the left ventricle with abnormal wall motion and contractile dysfunction
Histologically, what can you observe with DCMs?
Dilation
Myocyte hypertrophy
Interstitial fibrosis
What is arrhythmogenic right ventricular cardiomyopathy (ARVC)? What can it lead to?
Right ventricular failure & arrhythmias
Myocardium of right ventricle wall replaced by adipose & fibrosis
Causes ventricular tachycardia or fibrillation –> sudden death
What is the genetics behind ARVC? What is the pathogenesis?
Familial, Autosomal dominant
Defective cell adhesion proteins in desmosomes that link adjacent cardiac myocytes
What is Naxos syndrome?
ARVC w/ hyperkeratosis of plantar palmar skin surfaces
Mutations in gene encoding the desmosome-associated protein Plakoglobin
What is hypertrophic cardiomyopathy? Describe the genetic changes seen with the dz?
Genetic DO leading to myocardial hypertrophy & diastolic dysfunction, leading to decreased SV & often ventricular outflow obstruction
Numerous mutations known, involving sarcomeric proteins
-most commonly B-myosin heavy chain (B-MHC)
What is the morphology of hypertrophic cardiomyopathy?
Massive myocardial hypertrophy, often with marked septal hypertrophy
Microscopically, myocyte disarray
What are Sx of hypertrophic cardiomyopathy?
Harsh systolic ejection murmur, caused by ventricular outflow obstruction as the anterior mitral leaflet moves toward the ventricular septum during systole
What are the consequences of extensive hypertrophy in hypertrophic cardiomyopathy?
Foci of myocardial ischemia may occur
Left atrial dilation and mural thrombus
Diminished cardiac output and increased pulmonary congestion leads to exertional dyspnea
Arrhythmias
Sudden death (sudden, otherwise unexplained death in young athletes)
What is Restrictive Cardiomyopathy?
Decreased ventricular compliance (increased stiffness), leading to diastolic dysfunction (impaired filling), while systolic function of the LV remains normal
What may restrictive cardiomyopathy be secondary to? What changes to the heart will you see?
May be secondary to deposition of material within the wall (amyloid), or increased fibrosis (radiation)
Ventricles normal size, but BOTH atria can be enlarged
What is amyloid and how does it relate to restrictive cardiomyopathy?
Extracellular deposition of proteins which form an insoluble B-pleated
It is a common cause of RC
May be systemic (myeloma) or restricted to the heart (usually transthyretin)
-certain mutated versions of transthyretin are more amyloidogenic
Amyloid can involve different parts of heart, but when deposits are in interstitium of myocardium = restrictive cardiomyopathy
What is the classic stain associated with amyloid?
Congo red stain = apple green birefringence
