Module 2.6 - Cardiomyopathy Flashcards
1
Q
What is cardiomyopathy?
A
- Cardiomyopathies (CM) are diseases of the heart muscle that include a variety of myocardial disorders.
- There are structural and functional abnormalities in cardiomyopathy and some types are frequently genetic.
- Some original definitions describe CM as an idiopathic disorder causing cardiac muscle dysfunction that may result in systolic or diastolic dysfunction not due to atherosclerosis, hypertension or valvular disease.
- In clinical practice, the term cardiomyopathy is applied to patients with known cardiovascular disease – i.e, ischemic cardiomyopathy or hypertensive cardiomyopathy.
2
Q
What are the 3 types of cardiomyopathies?
A
- dilated
- hypertrophic
- restrictive cardiomyopathy
3
Q
What are the characteristics associated with dilated cardiomyopathy?
A
- Abnormal systolic function
- Dilated ventricles are seen without proportionate compensatory hypertrophy initially. Dilation impairs the contraction of one or both ventricles. It often becomes severe and is invariably accompanied by an increase in mass.
- Patients present with systolic heart failure symptoms
- Most common form of cardiomyopathy, responsible for over 10,000 deaths and 46,000 hospitalizations annually
- Dilation of the cardiac chambers is directly related to neurohormonal activation
- https://www.youtube.com/watch?v=Aao_4IfWOuI
4
Q
What are the characteristics associated with hypertrophic cardiomyopathy?
A
- Broadly defined as the presence of increased LV wall thickness
- Autosomal dominant disorder – an inherited trait that occurs in 1 out of 500
- Stiff left ventricle during diastole restricts ventricular filling.
- Ventricular hypertrophy occurs without dilation or a thickened septum
- Patients present with diastolic heart failure
- HCM can be further classified clinically according to the presence or absence of LV outflow tract (LVOT) obstruction. If this occurs, the disease is then named hypertrophic obstructive cardiomyopathy
- https://www.youtube.com/watch?v=8RnkKB8xvwA
5
Q
What are the characteristics of restrictive cardiomyopathy?
A
- Characterized by non-dilated ventricles, and impaired ventricular filling
- LV generally is not dilated, LVEF is generally normal
- May be a primary or idiopathic condition or due to infiltrative conditions (amyloid, sarcoid, hyper eosinophilic syndrome).
- Other etiologies include hemochromatosis that deposits excess iron in the cardiomyocyte sarcoplasm causing injury to the epicardium, myocardium and lastly endocardium.
- Fabry disease patients can exhibit restrictive cardiomyopathy due to the accumulation of globotriaosylceramide in tissues.
- Inadequate diastolic filling occurs
- Rigid ventricular walls are seen
- Patients present with diastolic dysfunction initially but can progress to systolic dysfunction when the myocardium is affected
- https://www.youtube.com/watch?v=Vwxco4YvxoQ
6
Q
What causes dilated cardiomyopathy?
A
- The most common etiologies include:
- ischemic heart disease
- ETOH abuse
- tachy arrhythmias that include sinus tachycardia and atrial fibrillation with rapid ventricular response (A fib with RVR)
- connective tissues disease – periarteritis, systemic lupus erythematosus (SLE)
- toxins (chemotherapy – especially Adriamycin)
- cocaine
- peri-partum state,
- idiopathic causes (unknown)
7
Q
What causes hypertrophic cardiomyopathy?
A
- Cause is idiopathic although hypertension has been associated with increased incidence.
- Also known as familial hypertrophic CM is characterized by an autosomal-dominant mode of inheritance.
8
Q
What causes restrictive cardiomyopathy?
A
- This is a relatively uncommon disease and in broad terms is described as noninfiltrative, infiltrative and storage diseases.
- These categories include hemochromatosis, sarcoidosis, amyloidosis, endomyocardial fibrosis (seen after open-heart surgery), exposure, and idiopathic causes.
9
Q
What are the subjective/objective findings associated with dilated cardiomyopathy?
A
- Increased jugular venous distention (JVD) - look for the right internal jugular vein to assess volume status
- Low pulse pressure – can indicate low cardiac output, low blood volume, shock. The normal range between the systolic and diastolic BP (pulse pressure) is 30-60 mmhg.
- S3 and S4 heart sounds – S3 may be heard after S1 and S2 and indicate heart failure. S4 may be heard as a results of blood flow against a stiff or hypertrophic ventricle
- Peripheral edema
- Rales
- Dyspnea
- Orthopnea
- Paroxysmal nocturnal dyspnea (PND)
- Mitral or tricuspid regurgitation - common due to the effect of chamber dilation on the valvular apparatus
- Cardiomegaly
10
Q
What are the subjective/objective findings associated with hypertrophic cardiomyopathy?
A
- Dyspnea
- Chest pain
- Syncope
- Murmur – harsh, crescendo-decrescendo systolic murmur heard best at the left sternal border
- S4 heart sound
- Maximized apical pulse
11
Q
What are the subjective/objective findings associated with restrictive cardiomyopathy?
A
- Dyspnea
- Fatigue
- Weakness
- Edema
- JVD
- Ascites
- Murmurs – regurgitant
- Kussmaul breathing possible
12
Q
What diagnostic tests should be used for dilated cardiomyopathy and what findings should be expected?
A
- Chest x-ray- You will see marked cardiac enlargement and interstitial pulmonary edema
- EKG – Possible findings include ST segment/T wave changes with left ventricular hypertrophy (LVH), right or left bundle branch block (RBBB or LBBB), and arrhythmias that include atrial fibrillation (AF), premature atrial contractions (PACs), premature ventricular contractions (PVCs) and ventricular tachycardia (VT).
- Echocardiogram – The diagnosis of DCM can be confirmed with echocardiography. Findings will include left ventricular dilation and dysfunction with low ejection fraction (EF). In addition to the changes in the LV, other findings can include RV ventricle enlargement and dysfunction. In these extreme cases, all four chambers are dilated causes bi-ventricular heart failure.
- Radionuclide ventriculography can assess LV function but is not the first test of choice
- Routine blood and urine chemistries
13
Q
What diagnostic tests should be used for hypertrophic cardiomyopathy and what findings should be expected?
A
- Chest x-ray – likely will see mild cardiomegaly but heart size can be normal
- EKG – Most common findings are ST segment and T wave abnormalities followed by evidence of LVH. You may see abnormal Q waves in anterolateral and inferior leads can be seen along with findings of LVH
- Echocardiogram – findings include LVH that is concentric, increased or at times normal EF
- Exercise stress testing and 24 hour Holter monitor screening to monitor heart rate and rhythm and help assess risk stratification for SCD
- Cardiac MRI – may be indicated if echocardiogram cannot confirm the diagnosis
- Routine blood and urine studies; Genetic testing in order to facilitate familial screening
14
Q
What diagnostic tests should be used for restrictive cardiomyopathy and what findings should be expected?
A
- Chest x-ray – There can be evidence of CHF, possible with pleural effusions. Cardiomegaly is possible and is usually mild to moderate.
- EKG – Possible findings include ST segment/T wave changes There may be arrhythmias, particularly AF
- Echocardiogram – thickened cardiac valves, increased wall thickness and normal or small left ventricle will be seen. LV function will be normal or mildly decreased.
- Routine blood and urine chemistries, serum iron concentrations and other possible indicators of hemochromatosis
- Cardiac MRI or catheterization – MRI shows thickening of the pericardium can identify and localize fat, iron or amyloid infiltration, inflammation, scar/fibrosis. Cardiac catheterization utilizes hemodynamic findings to assess for restrictive etiology
- Myocardial biopsy for definitive diagnosis
15
Q
How do you manage a patient with dilated cardiomyopathy?
A
- Treat the patient for HF by current guidelines with goal of improving symptoms and treating the co-morbid conditions
- Treat the underlying condition – ETOH abuse, DM, arrhythmias
- Vasodilators, especially combined with ACE inhibitors and nitrates should be considered
- Assess patient for need for oral anticoagulants to prevent emboli formation or treat thrombus formation in the LV
- If etiology is idiopathic, consider use of diltiazem. If ejection fraction is depressed, this is contra indicated
- Observe for arrhythmias to occur after initial diagnosis-atrial and ventricular arrhythmias are present in as many as one half of these patients and contribute to the high incidence of sudden cardiac death (SCD)
- Internal defibrillator – per heart failure guidelines and/or patient develops syncopal episodes related to arrhythmias
