3. Cardiomyopathy and Pericardial Disease Flashcards
what are the 3 main mechanisms of cardiac disease?
ventricular overloading, ventricular underloading, primary myocardial failure.
define ventricular overloading
mechanical abnormality causes excessive pressure or volume load on the ventricle. requirement for increased muscle tension or muscle shortening.
what can compensate for ventricular overloading?
concentric or eccentric hypertrophy
list some reasons for pressure overload
LV: hypertension, aortic stenosis, coarctation of the aorta
RV: pulmonic stenosis, cor pulmonale
most common reason for LV pressure load?
HTN
what might the heart do in order to compensate for a pressure load?
concentric LV hypertrophy allows it to create higher systolic pressures.
what is a cost of concentric hypertrophy?
LV is less compliant. RA and pulm venous pressures need to rise to fill LV. leads to backward failure/pulm congestion.
What are examples of volume overload?
LV: aortic regurg, mitral regurg, PDA, systemic arteriovenous fistula
RV: atrial septal defect, tricuspid regurg.
describe ‘high output failure’. what are some examples?
high output failure = marked increase in peripheral 02 demand, ie demand for incr cardiac output. requires same compensations as heart failure so pt will exhibit sx of CHF even though CO is elevated. Ex: hyperthyroidism, anemia
describe mitral regurg
leaky mitral valve -> blood regurgitates back from LV to RA during systole.
what does the heart do to compensate for mitral regurg?
to maintain adequate forward flow, the LV increases output by incr HR and incr SV. –>eccentric hypertrophy.
describe ventricular underloading. examples?
inadequate ventricular filling. failure occurs because the ventricle is underfilled. examples: mitral stenosis, hypovolemia, pericardial restriction, RV infarction
describe primary myocardial failure. examples?
myocardial failure = cardiomyopathy. pumping is handicapped by a primary abnormality of the ventricular muscle. examples: dilated cardiomyopathy, hypertrophic cardiomyopathy, coronary artery disease.
two main pathophysiologic forms of primary cardiomyopathy?
dilated and hypertrophic. basically look like eccentric and concentric but here the prob is muscle tissue itself, not demand placed on the heart.
dilated cardiomyopathy: syndrome or disease?
syndrome caused by many diseases
hypertrophic cardiomyopathy: syndrome or disease?
disease caused by many genetic defects
dilated cardiomyopathy: some possible causes?
genetic, postpartum, neuromuscular disease, alcohol, viral, autoimmune, metabolic, ischemic cardiomyopathy.
describe ischemic cardiomyopathy. is it a primary cardiomyopathy?
NO because it is caused by ischemia rather than primary muscle problem. scarred myocardium doesn’t contract well, leading to LV dilatation that resembles dilated cardiomyopathy.
by looking at the heart, how could you tell ischemic from primary cardiomyopathy?
ischemic will affect the LV: primary will have diffuse 4-chamber enlargement.
pathology of non-ischemic dilated cardiomyopathy at gross and microscopic levels?
gross: 4 chamber enlargement
micro: myocyte degeneration with irregular hypertrophy, atrophy, and fibrosis
results of dilated cardiomyopathy?
systolic pump failure, eccentric hypertrophy (attempt to compensate for decr shortening ability)
clinical features of dilated cardiomyopathy?
may be asx, may have biventricular failure.
If LH failure, dyspnea, orthopnea, LV enlargement, s3 gallop.
RH failure: peripheral edema, hepatomegaly, RV enlargement.
may see thromboembolism, arrhythmias.
treatment for Congestive heart failure?
- inotropic agents (digoxin)
- beta blockers
- diuretics
- vasodilators
- anticoagulants
- therapies specific to cause (abx, steroids, anti-toxin)
cause of hypertrophic cardiomyopathy?
disease caused by variety of different genetic defects.
pathology of hypertrophic cardiomyopathy, both gross and micro?
gross: concentric hypertrophy, mostly in septum but also LV
micro: myofibrillar disarray.
non-obstructive hypertrophic cardiomyopathy causes what?
diastolic disfunction: incr LV stiffness leads to reduced LV filling. leads to decr CO. compensation for this leads to higher LV filling pressures, which leads to pulmonary congestion (dyspnea)
hypertrophic cardiomyopathy can also be known as what (ASH)?
asymmetric septal hypertrophy
define subaortic stenosis
hypertrophied septum in pts with ASH leads to clinical picture looking like valvular aortic stenosis – septum impinges on mitral leaflet during systole, causing dynamic obstruction to LV outflow.
clinical symptoms of hypertrophic cardiomyopathy
- angina
- dyspnea. usually associated with angina and decr LV compliance.
- syncope, may be fatal. one of leading causes of death in young athletes
heart murmur associated with hypertrophic cardiomyopathy
systolic crescendo-decrescendo murmur at LL sternal border
what would increase the intensity of the murmur with hypertrophic cardiomyopathy?
- decr heart size: brings septum and anterior wall leaflet closer together
- increasing LV ejection velocity: by Bernoulli’s, leaflet pulled toward septum by blood streaming over surface.
drugs for hypertrophic cardiomyopathy?
beta blockers: relax myocardium, prolong diastolic filling rate, releave ischemia/angina, decr outflow obstruction.
surgery for hypertrophic cardiomyopathy?
remove septal muscle that is getting in the way.
three types of pericarditis?
- acute pericarditis
- pericardial tamponade
- chronic constrictive pericarditis
describe acute pericarditis. a few etiologies?
inflammation of the pericardium. infections, carcinoma, direct trauma, autoimmune
pathology of pericarditis: a few options for appearance
serous: early phase, with minimal cellular elements
serofibrinous: grossly appears shaggy (bread and butter)
purulent: pus associated with bacterial infection
clinical signs of pericarditis?
- pain: substernal, pleuritic, worse in supine. may be cardiophasic: rare but very telling.
- pericardial rub: may be scratchy or musical, loudest near L sternal border
- ECG: early - diffuse ST elev. late - diffuse Twave inversion
diagnosis of pericarditis?
clinical signs and ECG, ECHO, tissue/fluid analysis
therapy for pericarditis?
drugs: abx. pericardial drainage for bacterial inf. salicylates, steroids
describe pericardial tamponade
pericardial fluid accumulation, sufficient to compress heart and cause cardiogenic shock. (via collapsed vasculature and decr filling)
cause of pericardial tamponade?
usually due to acute hemorrhage.
what does pericardial tamponade cause?
restriction of diastolic filling –> underloading, decr CO.
compensation for the decr CO of pericardial tamponade/
sympathetic stimulation, high venous pressures
clinical signs of pericardial tamponade?
rapid onset, shock, tachycardia, diaphoresis, Beck’s Triad
What is Beck’s triad?
3 symptoms seen in pericardial tamponade:
- paradoxical pulse: accentuation of the normal inspiratory drop in BP
- incr systemic venous pressure
- quiet heart because insulated by fluid.
what is the clinical picture of chronic constrictive pericarditis?
- usually occurs long after an episode of acute pericarditis.
- fibrotic pericardium restricts ventricular filling with diastole, so diastolic heart failure
- looks like heart failure rather than shock
- incr diastolic pressure more on R side, so presents as Rsided heart failure
clinical signs of chronic constrictive pericarditis?
- Rsided heart failure, with small heart
- sometimes paradoxical pulse
- Kussmaul sign
- pericardial knock (similar to S3 gallop, due to early rapid ventricular filling)
what is Kussmaul sign?
neck veins distended on inspiration rather than normal collapse.
