Card Set Information

2011-01-16 16:18:15

Heart valves and Heart sounds
Show Answers:

  1. Cause of sound when valves close
    vibration of the taut valves immediately after closure along wont vibration of adjacent walls of the heart and major vessels
  2. Length of heart sounds
    • first 0.14
    • second 0.11
    • the second os hotter because the semilunar valves are more taut than the AV valves so they vibrate for a shorter time
  3. Frequency of heart sounds
    • the second usually has a higher frequency
    • 1 the tautness
    • 2 greater elastic coefficient of the arterial walls that provide the principle vibrating chamber
  4. Heart sounds
    • first is longer with a lower frequency
    • second is shorter with a higher frequency
  5. Third heart sound
    • weak rumble in the middle third of diastole
    • oscillation of blood between the walls of the ventricle
    • reason it does not appear until the middle of diastole is that in the early part of diastole the ventricles are not filled enough to create the elastic tension needed to reverberate
    • very low frequency
  6. S4
    • the atrial heart sound
    • heard when the atria contract and blood rushes into ventricle
  7. Phenocardiogram
    special microphone to record heart sounds
  8. Greatest cause of valvular lesions
    rheumatic fever
  9. Rheumatic fever
    • autoimmune disease
    • begins with infection by Group A hemolytic streptococci; sore throat, scarlet fever, middle ear infection
    • the streptococci release proteins which antibodies are formed
    • the antibodies react not only with the proteins but also with other proteins of the body
    • Inflammation occurs along the edges of the heart valves
    • mitral>aortic
    • The inflammation on adjacent leaflets cause them to become stuck and fuse together. the edges also become solid, scarred masses
  10. Systolic murmur of aortic stenosis
    • because of resistance to ejection LV pressure can reach 300, this creates a nozzle effect.
    • this turbulent blood vibrates the walls of the aorta and causes the murmur
    • If severe may cause a thrill, being able to feel the vibration on the chest
  11. Diastolic murmur of aortic regurge
    • during diastole blood flows backward from the aorta into the ventricle
    • blowing murmur
  12. systolic murmur of mitral regard
    • blood flows backward through the mitral valve during systole
    • pansystolic murmur heard at the apex of the heart
  13. Diastolic murmur of mitral stenosis
    • left atrial pressure can rise to 30 mmHg
    • not heard until middle third of systole with an increase at the end due to atrial contraction
  14. Loudest and softest murmur
    • Ao stenosis id loudest
    • mitral stenosis is softest
  15. Effect of Ao stenosis and regurg on stroke volume
    • they both decrease stroke volume
    • stenosis does not allow the LV to empty entirely
    • regurge allows blood to flow back into the ventricle
  16. Compensatory mechanisms of stenosis and regurge
    • hypertrophy of the LV; due to increased workload. In regurge the LV also enlarges to hold the extra blood. Allows the LV the generate a much higher pressure and stroke volume
    • Increases in blood volume; results from an initial drop in arterial blood pressure and circulatory reflexes that are induced by the drop in pressure
  17. consequence of chronic aortic valve lesion
    • the LV finally cannot keep up with the workload
    • as a consequence the LV dilates and output begins to fall
    • blood dams up in the left atrium and in the lungs
    • left atrial pressure rises and causes pulmonary edema
  18. Why does lethal pulmonary edema not occur until high pressures
    the lung lymphatic system enlarges and carries fluid away
  19. how atrial enlargement effects conduction
    • the enlargement increases the distance that the impulse must travel in the atrial wall
    • may become so long it causes a circus rhythm
    • mitral disease usually cause atrial fib
  20. valvular lesions during exercise
    • problems become exacerbated due to increased return to the heart
    • can lead to lethal pulmonary edema or left heart failure
    • diminished cardiac reserve
    • muscles fatigue rapidly
  21. Three major types of congenital anomalies
    • stenosis of some point in the heart or a major vessel; valve or coarctation of the aorta . pulmonary edema and reduced cardiac output
    • left to right shunt
    • right to left shunt
  22. closure of the ductus arterioles
    • the lungs inflate during the first breath reducing the pulmonary resistance
    • at the same time the aortic pressure increases from the cessation of blood through the umbilical artery
    • blood begins to flow backward through th ductus causing it to close, the blood now flowing through it has a much higher O2 concentration causing this constriction
  23. Persistant ductus arteriosus
    • during early life no effect
    • as the child grows the pressure gradient between the aorta and pulmonary artery grows which increases flow backward to the lungs
    • no cyanosis until later in life when the heart fails or the lungs become congested
  24. major effects of a PDA
    • decreased cardiac reserve and respratory reserve
    • LV must pump much more blood and become hypertrophied, when exercising the heart can never pump enough blood as needed
    • will faint from moderate activity
    • The extra flow through the lungs leads to high pulmonary pressure and to congestion and edema
    • no murmur at birth van be heard then will become a machine type murmur through the entire cardiac cycle. waxes and wanes with each beat
  25. Most common cause of blue baby
    tetralogy of fallout
  26. four abnormalities of tetralogy of fallot
    • overriding aorta, originates from the RV or a hole in the septum
    • pulmonary valve stenosis
    • VSD
    • right ventricle hypertrophy
  27. circulatory dynamics of tetralogy
    right to left shunt, right ventricle directly to the aorta
  28. diagnosis of tetralogy
    • cyanotic
    • high systolic RV pressure
    • enlarged RV on xray
    • angiogram shows VSD
  29. most common cause of congenital heart disease
    • viral infection during pregnancy, first trimester
    • german measles
    • some are hereditary