Cardiomyopathy Flashcards
Disorders 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
Excludes cardiac dysfunction caused by structural heart disease: CAD, primary valve disease, HTN
Cardiomyopathy involves which part of the heart and causes dysfunction of systole, diastole, or both?
LV
diagnostic modalities of Cardiomyopathy include:
- echo
- nuclear imaging
- coronary angiography w/ L ventriculography
- Cardiac MRI
resulting dysfunction can be transient or permanent
how does Systolic dysfunction happen?
decrease in myocardial contractility nd reduction in LVEF
Eventually fails and HF develops
what Compensatory mechanisms in systolic dysfunction aim to maintain cardiac output:
- LV enlargement resulting in higher stroke volume
- Frank-Starling relationship (↑stretch = ↑contractility)
how does Diastolic dysfunction happen?
cardiac dysfunction d/t abnormal LV relaxation and filling
Accompanied by elevated filling pressures
T/F: diastolic dysfunction can happen with or w/o systolic dysfunction
T
Always present if systolic dysfunction occurs
Why is diastolic dysfunction often underestimeated/missed?
more difficult to quantify on echo
An inflammatory, infiltrative process involving the myocardium caused by infectious and noninfectious conditions
Myocarditis
May be acute, subacute, or chronic
what can Myocarditis lead to?
- necrosis and/or degeneration of myocytes
- myocardial dysfunction and dilated cardiomyopathy
Pathogenesis of Myocarditis
Varies depending on the underlying cause (which is often undetermined)
- Host-mediated: direct cytotoxic effect of the causative agent
- Autoimmune-mediated: secondary immune response
Myocardial damage occurs in 2 main phases:
- Acute phase:
- First 2 weeks
- Myocyte death is a direct result of the causative agent, leading to cell-mediated cell toxicity - Chronic phase:
- After 2 weeks
- A result of an inappropriate, overactive immune response
what are the MC infectious causes of myocarditis
- adenovirus
- coxsackie B virus
- cytomegalovirus
- COVID
what are the MC cardiotoxin causes of myocarditis
- alcohol
- anthracyclines
- cocaine
Epidemiology of Myocarditis
- Frequency is poorly defined d/t variability of clinical presentation
- MC 20-50 y/o
- Men have a slightly higher mortality rate
myocarditis presentation
- days-weeks after acute febrile illness / respiratory infection - No known underlying cardiac pathology
- SOB, pleural/pericardial chest pain, +/- fever, chills—Could also present with HF
- gradual or abrupt with decreased cardiac output, shock, and severely depressed LV systolic function
- Palpitations, syncope, or sudden death may also occur d/t arrhythmias
PE of myocarditis
- pericardial friction rub, tachycardia, S3 or S4, murmur of mitral or tricuspid regurg if ventricular dilation is severe
- HF → volume overload
initial testing for 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
other testing for myocarditis (not initial)
- Labs: CRP, ESR (elevated), CBC (eosinophilia), +/- rheumatologic workup, serum viral antibody titers, BNP (in setting of HF)
- TTE: critical!
- cardiac MRI (CMR)
- suggests myocarditis, but sensitivity and specificity are limited and time-dependent
what testing allows visualization of the myocardium, assessment of ventricular function, helps r/o / assess other pathology (regurg)
TTE
what testing helps assess extent of inflammation, myocyte necrosis and scarring, ventricular size / shape changes, wall motion abnormalities, and pericardial effusion
cardiac MRI (CMR)
Endomyocardial biopsy (EMB) should only be obtained if ?
there is a high probability that results will change patient management
tx for infectious myocarditis
- Consult Cardiology!
- tx directed toward presentation
- LVEF <40% → ACE-I, BB
- NSAIDs (possibly Colchicine) for myopericardial CP
- Arrhythmia management
- Trials using immunosuppressive therapies, corticosteroids, IVIG, and antivirals have not shown benefit
noninfectious myocarditis MCC by?
medications, illicit drugs, and toxic substances