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.