Cardiomyopathy Flashcards
epidemiology of cardiomyopathies
accounts for 5-10% of heart failure of the 5-6 million pts with this diagnosis in the US
etiology of cardiomyopathy
- primary intrinsic - d/t myocardial dz - genetic disorders of myocardial fibers
- secondary intrinsic cardiomyopathy d/t systemic dz or to another cause - sarcoidosis, hemochromatosis, chronic anemia
3 main patterns of cardiomyopathies
- dilated
- hypertrophied
- restrictive
s/s of cardiomyopathies
- DOE d/t increased LV/LA/PA pressure
- fatigue - decreased CO
** with advancing dz there is progressive DOE with mild activity, orthopnea and PND
definition of dilated cardiomyopathy
most common 90% of cases
-an enlarged LV (dilation with contractile dysfunction) with decreased systolic function and ejection fraction (EF
epidemiology of dilated cardiomyopathy
causes 25% of all cases of heart failure
blacks more affected
men>women
age of onset 20-50yo
pathophys of dilated cadiomyophaty
impairment of ventricular contractility
- systolic failure is more pronounced than diastolic failure
- floppy or flabby thin and weak ventricles and atria
- enlarged - bw 2-3x the normal weight
- can sometimes see ventricular thickness (compensated heart failure)
causes of intrinsic dilated cardiomyopathy
genetic - 20-50% primary type
- idiopathic
- CAD as secondary cause
- Rx: alcohol, doxorubicin, adriamycin
- thyroid dz
- peripartum cardiomyopathy
- infections: coxsackie HIV lyme’s
- Chronic tachycardia
- sarcoidosis
- amyloidosis
- hemochromatosis
- diabetes
s/s of dilated cardiomyopathy
pulm rales elevated JVD cardiomegaly s3 gallop murmurs of mitral or tricuspid regurg (systolic) periperhal edema ascites
s/s in dilated cardiomyopathy in severe heart failure
- cheyne-stokes breaking - endstage LHF
- pulsus alternans - end stage LHF
- pallor
- cyanosis
diagnostic studies for dilated cardiomyopathy
- echo - confirms presence of dilated ventricle and reduced systolic function EF
treatment of dilated cardiomyopthy
- ACEi, ARBs, BB, diuretics, aldosterone antagonists - get rid of fluid
- sodium restriction
- anticoags d/t high risk of embolization
- digoxin as adjunctive tx
- tx underlying causes
definition of hypertrophic cardiomyopthy
obstructive vs non-obstructive
-increased LV hypertrophy w/o the presence of an underlying cause such as valvular dz (with an increase in pressure greadients) volume overload or systemic HTN
epidemiology of hypertrophic cardiomyopathy
- age of onset - any, but commonly seen in post puberty and young athletes (20-40)
- most common genetic cause of cardiac death in young people including trained athletes
main dysfunction in hypertrophic cardiomyopathy
increased diastolic filling pressure (diastolic failure or compliance impairment) from a stiff and small chambered hypertrophied LV
hypertrophic cardiomyopathy - increased wall thickness will
- decrease LV systolic stress (wall tension) and increase the EF (no outflow obstruction-nonobstuctive)
- can result in a relative empty ventricle at end systole and a supranormal EF of 50-80% if there is no obstruction to outflow
hypertrophic cardiomyopathy - obstructive
outflow track obstruction
characteristic asymmetric inter ventricular septal hypertrophy that can obstruct outflow by narrowing the LV outflow track and decreasing the EF
causes of intrinsic hypertrophic cardiomyoptahy
- genetic (in 50-80% of cases, most common genetic cardiovascular dz)
- idiopathic
- infants of diabetic mothers
pathophys of hypertrophic cardiomyopathy
- genetic mutations of myofibril cells and contractile elements results in hyper contractility and a small and stiff LV
- hyper contracted myocardium is not able to relax during diastole resulting in diastolic dysfunction and decreased filling during diastole
pathophys of left ventricular outflow track obstruction
- obstruction causes: decreased cardiac output
- obstruction can be made wore by: tachycardia, extreme exercise, valsalva, digoxin, vasodilators, diuretics, catecholamines, hypertrophy with increased contractile force, decrease in ventricular volume or afterload
other causes of hypertrophic cardiomyopathy
mitral regurg, myocardial ischemia, arrhythmias
definition of cardiomyopathy
an intrinsic dz of the myocardium that casues hemodynamic dysfunction
ex. heart failure (left and/or right beiventricular failure)
- cause is usually non ischmic although it can be secondary to multi vessel dz
- it is also not related to valvular dz or systemic HTN
s/s of hypertrophic cardiomyopathy
- some pts present from mild to severe symptoms
- many pts will lead an uneventful dz course
- there are some pts at increased risk of sudden death: need for a good family hx and symptom assessment
- especially in young people and trained athletes sudden death - atrial and ventricular arrhythmias - d/t persistently high atrial/ventricular pressures and dilation
- sustained PMI
- loud S4 - from stiffened hypertrophied ventricle
- systolic ejection murmur heard best at left lower sternal border - decreases with squatting (increases LV filling), increases with valsalva and standing (decreases LV size and LV filling) murmur does not radiate to carotids like aortic stenosis
- bisferiens carotid pulse (biphasic) - carotid pulse with 2 upstrokes double peak, characteristic of HCM
common symptoms of hypertrophic cardiomyopathy
- progressive DOE in 90% of pts, anginal CP 70-80% of pts, presyncope and syncope (20-50%) after valsalva maneuver or exercise, palitaitons
- cardiac failure - d/t LV stiffness and increased end diastolic pressure/volume and decreased CO and cardiac O2 supply
diagnostic studies for hypertrophic cardiomyopathy
- echo
- definitive and diagnostic - will show pressure gradient across aortic valve
- shows small and hyper contractile LVH
- delayed relaxation and filling of the LV in diastole
- shows turbulent flow and pressure gradient in the outflow track and mitral regurg - cardiac cath
- confirms echo findings: also rules out CAD - ECG
- LVH in symptomatic pts
- atrial and or ventricular fibrillation, but normal in 25% of pts with localized hypertrophy
tx and prevention of hypertrophic cardiomyopathy
all pts need to avoid strenuous exercise but low to moderate exercise is fine
- maintain hydration at all times
- dehydration decreases preload and after load exacerbating outflow track obstruction
- screen all 1st degree relatives with ECHO
- genetic testing
medical tx
- BBs are 1st line therapy in symptomatic pts
- slows HR and improves diastolic filling of the stiffen LV
- decreases outflow track pressure gradient
- relieves angina by decreasing O2 demand - verapamil
- decreases ionotropy and chronotropy
- improves diastolic relaxation - disopyramide as adjunctive tx
- negative inotropic action decreases LV pressure gradient and improves CO - diurectic
- to correct high pulm capillary wedge pressure
surgical tx
- myotomy-myomectomy
- for pts unresponsive to medical tx - mitral valve replacement if necessary
restrictive cardiomyopathy
-rare cause of intrinsic cardiomyopathy
-amyloidosis is main cause
-other causes: hemochromatosis, sarcoidosis, scleroderma, post radiation, diabetes
-not due to valvular, CAD or systemic HTN
-idiopathic
men>women
onset>age 40
pathophys of restrictive cardiomyopathy
-characterized by impaired LV/RV diastolic filling and volume with reasonably preserved contractility but decreased ventricular compliance
-small and stiff RV/LV restricting diastolic filling - causes elevated atrial, pulm and systemic venous pressures, no or little hypertrophy or cardiomegaly is seen
-right hear failure dominates over left sided heart failure - pulmonary systemic HTN is present
difference bw restrictive cardiomyopathy and constrictive pericarditis
-no ventricular interdependence or pulsus paradoxus
-pulmonary arterial pressure is elevated in restrictive cardiomyopathy but normal in uncomplicated constrictive pericarditis
s/s of restrictive cardiomyopathy
mostly due to elevated ventricular diastolic pressure that restrict filling which causes
- pulmonary and systemic venous pressure
- DOE, orthopnea - pulmonary HTN
- right sided heart failure
- elevated JVD
- hepatomegaly,ascites
- edema
- reduced CO and fatigue from underfilled ventricles
diagnostic studies
- echo: small thickened LV, no cardiomegaly
- endomyocardial bx to confirm amyloidosis
- ECG: low voltage, atrial/ventricular arrhythmias
- CXR: normal size ventricles, atrial enlargement
treatment of restrictive cardiomyopathy
treat underlying dz (amyloidosis
- anti-plasma cell therapy under the care of a specialist (hematologist)
- tx diastolic heart failure
- BBs - help slow HR and improve LV filling
- loop diuretics
- thiazides
- aldosterone antagonists
