Chapter 11: Cardiomyopathies and Myocarditis Flashcards
What is cardiac disease due to?
intrinsic myocardial dysfunction
What is the ‘name’ for intrinsic myocardial dysfunction
cardiomyopathies (literally: heart muscle diseases)
True/false: cardiomyopathies can be primary or secondeary
True!
Many disorders can be the cause of cardiomyopathies. Some are: inflammatory (i), immunologic (ii), systemic metabolic (iii), muscular dystrophies, and genetic disorders of myocardial fibres. Name examples of i, ii and iii (illustration)
i: myocarditis ii: sarcoidosis iii: hemochromatosis
Is the cause of cardiomyopathies often known?
No (we call this ‘idiopathic’)
There are many ways to classify cardiomyopathies, but for purposes of general diagnosis and therapy, however, three time-honored clinical, functional and pathologic patterns are recognized. Name those three.
- Dilated cardiomyopathy (DCM) (including arrhythmo- genic right ventricular cardiomyopathy) 2. Hypertrophic cardiomyopathy (HCM) 3. Restrictive cardiomyopathy (from most to least frequent/common)
Read this through
Okay
Explain dilated cardiomyopathy (DCM)
Dilated cardiomyopathy (DCM) is characterized by progressive cardiac dilation and contractile (systolic) dysfunction, usually with concurrent hypertrophy; regardless of the cause, the clinicopathologic patterns are similar.
Is DCM mostly acquired genetically or secondary?
Genetically (20-50%)
DCM can however be a result from various acquired myocardial insults. Name some
- Myocarditis - Toxicities - Pregnancy (peripartum cardiomyopathy) - stress provoked - tachycardia induced
In this picture you see the major forms of cardiomyopathy. Link the numbers (i-vi) with the correct diagnosis: a) dilated cardiomyopathy b) hypertrophic cardiomyopathy c) normal d) restrictive cardiomyopathy
i = c (normal) ii = a (dilated cardiomyopathy) iii = b (hypertrophic cardiomyopathy) vi = d (restrictive cardiomyopathy)
What are general causes that can lead to end-stage DCM besides genetics?
Infection - alcohol or other toxic exposure - peripartum cardiomyopathy - iron overload
What is the fundamental defect in DCM?
Ineffective contraction (in end-stage, the cardiac ejection is typically less than 25% (normally l50-65%))
What, besides ineffective contraction, are clinical features of DCM?
Secondary mitral regurgitation and abnormal cardiac rhythms are common, and embolism from intracardiac (mural) thrombi can occur
What is arrhythmogenic right ventricular cardiomopathy?
Arrhythmogenic right ventricular cardiomyopathy is an autosomal dominant disorder that classically manifests with right-sided heart failure and rhythm disturbances, which can cause sudden cardiac death
What is hypertrophic cardiomyopathy (HCM) characterized by?
Hypertrophic cardiomyopathy (HCM) is characterized by myocardial hypertrophy, defective diastolic filling, and— in one third of cases—ventricular outflow obstruc- tion.
Fill in: In arrhythmogenic right ventricular cardiomyopathy, the wall is *thickened/thinned*. In hypertrophic cardiomyopathy, the wall is *thickened/thinned*
Thinned, thickened respectively
What other disorders should be clinically distinguished from hypertrophic cardiomyopahy (because they are similar, but different treatment)?
HCM needs to be distinguished clinically from disorders causing ventricular stiffness (e.g., amyloid deposition) and ventricular hypertrophy (e.g., aortic stenosis and hypertension).
True/false: Most cases of HCM are caused by missense mutations in one of several genes encoding proteins that form the contractile apparatus
True
At what age is HCM, DCM, RCM and ARVC often diagnosed?
- HCM: postpubertal growth spurt
- DCM: 20-50y/o
- RCM: 4-6y/o (but can be at any age)
- Arrhythmogenic: 20-40y/o
Explain (elaborately) the clinical features (NOT complications) of HCM (i don’t think we have to learn this)
t is characterized by massive left ventricular hypertorphy associated with (paradoxically) a markedly reduced stroke volume. This latter occurs as a consequence of impaired diastolic filling and overall smaller chamber size. In addition, roughly 25% of patients have dynamic obstruction to the left ventricular outflow by the anterior leaflet of the mitral valve. Reduced cardiac output and a secondary increase in pulmonary venous pressure cause exertional dyspnea, with a harsh systolic ejection murmur. A combination of massive hypertrophy, high left ventricular pressures, and compromised intramu- ral arteries frequently leads to myocardial ischemia (with angina), even in the absence of concomitant CAD.
What are the major clinical complications of HCM?
Atrial fibrillation with mural thrombus formation, ventricular fibrillation leading to sudden cardiac death, infectious endocarditis of the mitral valve and CHF.
How is restrictive cardiomyopathy characterized?
By a primary decrease in ventricular compliance, resulting in impaired ventricular filling during diastole (simply put, the wall is stiffer)
True/false: restrictive cardiomyopahy is idiopathic
Yes, but it may also be associated with systemic diseases that affect the myocardium (e.g. radiation fibrosis, amyloidosis, sarcoidosis, errors metabolism)
