Cardiomyopathy Flashcards
Disorder characterized by morphologically and functionally abnormal myocardium in the absence of any other disease that is sufficient, by itself, to cause the observed phenotype
Cardiomyopathy
What does cardiomyopathy exclude?
Cardiac dysfunction caused by structural heart disease such as CAD, primary valve disease, HTN
What are the traditional classifications of cardiomyopathy?
- Dilated cardiomyopathy
- Restrictive cardiomyopathy
- Hypertrophic cardiomyopathy
What are the WHO/ISFC classifications of cardiomyopathy?
- Dilated, Hypertrophic, Restrictive
AND - Arrhythmogenic right ventricular cardiomyopathy/dysplasia
- Unclassified cardiomyopathies
In addition to the traditional classification and WHO/ISFC classification, cardiomyopathy can be classified as what?
- Intrinsic vs extrinsic
- Primary vs secondary
- Ischemic vs nonischemic
What are types of familial/genetic cardiomyopathy?
- Unidentified gene defect
- Disease sub-type
What are types of non-familial/non-genetic cardiomyopathy?
- Idiopathic
- Disease sub-type
What does cardiomyopathy predominantly involve?
- LV
- Dysfunction of systole, diastole, or both
How can the presentation of cardiomyopathy range?
- Asymptomatic to decompensated CHF to cardiac arrest
What are diagnostic modalities for cardiomyopathy?
- Echocardiography
- nuclear imaging
- coronary angiography w/ left ventriculography
- Cardiac MRI
Dysfunction can be transient or permanent
What does systolic dysfunction cause?
- Decrease in myocardial contractility and reduction in LVEF
- Compensatory mechanisms of LV enlargement resulting in higher stroke volume
- Frank-Starling relationship (increased stretch= increased contractility
- Eventually will lead to HF
What does diastolic dysfunction cause?
- Cardiac dysfunction d/t abnormal LV relaxation and filling, accompanied by elevated filling pressures
What is the relationship between diastolic dysfunction and systolic dysfunction?
May occur with or without systolic dysfunction but always present if systolic dysfunction occurs
What is one problem with diastolic dysfunction diagnosis?
More difficult to quantify on echo so often underestimated or missed
What is myocarditis?
- Inflammatory, infiltrative process involving the myocardium caused by infectious and noninfectious conditions
- May be acute, subacute, or chronic
- Results in necrosis and/or degeneration of myocytes
What can myocarditis lead to?
- Myocardial dysfunction
- Dilated cardiomyopathy
What is the pathogenesis of myocarditis?
- Varies depending on underlying cause (often undetermined)
- 2 main mechanisms: host-mediated and autoimmune mediated
What causes host-mediated myocarditis?
direct cytotoxic effect of the causative agent
What causes autoimmune-mediated myocarditis?
secondary immune response
What are the 2 main phases of myocardial damage in myocarditis?
- Acute phase and chronic phase
What are characteristics of the acute phase of myocarditis?
- First 2 weeks
- Myocyte death is a direct result of the causative agent, leading to cell-mediated cell toxicity
What are characteristics of the chronic phase of myocarditis?
- Post 2 weeks
- Result of inappropriate, overactive immune response
What are 3 infectious causes of myocarditis to know?
- Adenovirus (COVID-19)
- Coxsackie B virus
- Cytomegalovirus
What are 3 noninfectious causes of myocarditis to be aware of?
Cardiotoxins:
- Alcohol
- Anthracyclines
- Cocaine
Which group has a slightly higher mortality rate due to myocarditis?
Men
What is the epidemiology of myocarditis?
- Frequency poorly defined due to variability of clinical presentation
- MC in patients 20-50 y/o
What is the presentation of myocarditis?
- Days to few weeks after onset of acute febrile illness/respiratory infection
- No known underlying cardiac pathology***
- SOB, pleural/pericardial chest pain, +/- fever, chills
- Could present with HF
- Palpitations, syncope, or sudden death may occur due to arrhythmias
What are the classic symptoms of myocarditis?
- SOB, pleural/pericardial chest pain, +/- fever, chills
If a patient with myocarditis has HF, what presentation may be present?
Gradual or abrupt
* Decreased cardiac output
* shock
* Severely depressed LV systolic function
What will be present on physical exam of myocarditis?
Heart auscultation:
* Pericardial friction rub
* Tachycardia
* S3 or S4
* Murmur of mitral or tricuspid regurgitation if ventricular dilation is severe
Heart failure: Volume overload
What initial testing should be performed for myocarditis?
- EKG
- Cardiac biomarkers
- CXR
What will be findings of the EKG, cardiac biomarkers, and CXR in myocarditis?
- EKG: sinus tachycardia, dysrhythmias, ventricular ectopy (PVCs), ST-T changes
- Cardiac biomarkers: elevated troponin levels common (esp. in rapid onset myocarditis)
- CXR: typically nonspecific, but may see cardiomegaly, pulmonary edema, pleural effusion
What additional testing can be performed for myocarditis?
- Labs: CRP, ESR (elevated), CBC (eosinophilia), +/- rheumatologic workup, serum viral antibody titers, BNP (in setting of HF)
- Transthoracic echo
- Cardiac MRI
- Endomyocardial biopsy
Does a transthoracic echo need to be performed in myocarditis? Why or why not?
- Yes! It is critical
- Allows visualization of myocardium, assessment of ventricular function, helps to r/o other pathology
Why would a cardiac MRI be performed?
- Helps assess extent of inflammation, myocyte necrosis and scarring, ventricular size/shape changes, wall motion abnormalities, and pericardial effusion
- Can suggest myocarditis, but sensitivity and specificity are limited and time dependent
Cardiology will decide whether or not to perform cardiac MRI
What does concrete confirmation of myocarditis require?
Histological evidence
Most cases are presumed
When would endomyocardial biopsy be obtained?
If there is a high probability that results will change patient management
Not our call (cardiology) and has limited sensitivity and specificity
When is endomyocardial biopsy recommended by the AHA/ACC?
- Fulminant, unexplained HF (new onset <2 weeks w/hemodynamic compromise)
- Unexplained new onset HF 2 weeks-3 months w/dilated LV, new ventricular arrhythmia, Mobitz II 2nd degree AV block, 3rd degree block or failure to respond to usual care in 1-2 weeks