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| | *continued here from [[Lecture 11 Fetal Physiology]] on 01/31/11 at 11:25AM. | | *continued here from [[Lecture 11 Fetal Physiology]] on 01/31/11 at 11:25AM. |
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| - | ==Congenital and Acquired Heart Anatomical Abnormalities==
| + | PDWeWK I appreciate you sharing this article.Really thank you! Much obliged. |
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| - | ===Objectives===
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| - | *The diagnosis of most heart abnormalities begins with the stethoscope and a knowledge of the heart cycle. For each of the abnormalities studied, when would a murmur be heard during the heart cycle and over which valve, if a valve is involved?
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| - | *In the six abnormalities studied, which would have enlarged end diastolic volumes? In each situation, why is the EDV enlarged?
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| - | *In the six abnormalities studied, which would have reduced end diastolic volumes? In each situation, why is the EDV reduced?
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| - | ===Statistics===
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| - | *9 of every 1000 live births has a heart defect that requires intervention.
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| - | *1.7 of every 1000 children develops type 1 diabetes
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| - | *So cardiac abnormalities are far, far more common than T1DM.
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| - | *We do a ton of cardiac procedures (procedure, cost, death rate):
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| - | **Not cheap
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| - | **Coronary Artery Bypass Graft, $85,653, 2.1%
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| - | **Angioplasty Procedure, $44,110, 0.8%
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| - | **Diagnostic Catheterization, $25,322, 0.9%
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| - | **Pacemaker, $43,101, 0.9%
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| - | **Implantable Defibrillator, $99,845, 0.8%
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| - | **Valves/Septal Defect, $119,918, 5.1%
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| - | **Cardiac catheterizations
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| - | ***Much less expensive than surgeries
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| - | ***1.3 million!
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| - | ***Mostly for coronary artery disease
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| - | ***Many of these are done in children to detect problems.
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| - | *We do a ton of open heart surgeries, too:
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| - | **Valve replacements: 106,000
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| - | **Bypass (cardiac revascularization): 469,000
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| - | **Heart transplant: 2,192
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| - | **Septal Defects: 124,000
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| - | **Total open-heart procedures: 699,000
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| - | ===Atrial septal defect===
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| - | *'''Atrial septal defect''' is the '''second most common congenital heart defect'''.
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| - | *Often there is a physical hole between the atrial other than the foramen ovale.
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| - | *Can sometimes be repaired with a patch.
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| - | *Once fixed, pt is able to grow bigger and strong and to exercise much more strenuously.
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| - | *Atrial septal defects allow movement of blood from the left atrium to the right atrium because blood pressure is higher in the left atrium.
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| - | *S&S:
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| - | **There isn't usually hypoxia at rest
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| - | ***Because blood is passing left to right
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| - | ***However, the systemic loop will have less capacity to exercise, etc.
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| - | **The heart is limited to normal or moderate exercise because it is getting less blood than it needs for extreme exercise.
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| - | **Causes increased pulmonary blood pressure because of high right ventricular output (because right atrium is extra full because left atrium donated some extra).
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| - | ***Increased bp in the pulmonary circuit can generate hypertrophy of the arterial vascular muscle.
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| - | ***Because oxygenated blood is getting pushed to the lungs, they contract slightly causing increased pulmonary resistance.
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| - | **Pulmonary hypertension (see two points above)
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| - | **Right ventricular chamber may enlarge (in response to higher preload)
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| - | **Right ventricular muscular hypertrophy
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| - | **Heart sounds may be generated:
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| - | ***Diastolic murmur as blood is pushed form left atrium to right atrium,
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| - | ****This is a soft sound or may not be audible at all.
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| - | ***3rd or 4th heart sound because of right ventricle's stretched state,
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| - | ***Louder pulmonary valve sound because of higher pulmonary pressure,
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| - | ***Splitting of second heart sounds because the right ventricle takes longer to pump against an increased afterload.
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| - | **Right ventricular failure, eventually.
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| - | ===II. Ventricular Septal Defect===
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| - | *The ventricular septum is complicated
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| - | **It is solid muscle
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| - | **It is weaved together like a basket
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| - | **If not weaved just correctly, there can be opening form one ventrical to the next.
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| - | **There is also a dense connective tissue at the top of each ventricle that if not well connected can allow passage of blood.
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| - | *These defects can be really big causing a large load on the ventricle.
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| - | *Ventricular septal defect is '''the most common congenital cardiac defect'''.
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| - | *This is a hole between the two ventricles.
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| - | *Small defects tend to close spontaneously in chidlren.
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| - | *75% of cases require surgery before the age of 5.
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| - | *Causes all the same problems as atrial defect.
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| - | *In addition, if the hole is large enough, there will be increased work required by the left ventricle.
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| - | *S&S:
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| - | **Ventricular systole murmur volume is indirectly proportional to the area of the hole.
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| - | **Left ventricle is overstretched and fails.
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| - | **Risk of endocarditis is increased because of shear flow over edges of shunt.
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| - | ***This can generate clots on the septum that get washed into the coronary arteries, the brain, the gut, the respiratory tract, etc.
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| - | ===III. Semilunar valve stenosis===
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| - | *With semilunar valve stenosis there is a problem with ventricular ejection because the aortic or pulmonary valves are stiffened.
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| - | *Recall that work is the stroke volume multiplied by the pressure (W = SV * P).
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| - | *When the valve is stiff, it increases the work the ventricles must do to eject the blood.
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| - | *S&S:
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| - | **Ventricular hypertrophy to maintain cardiac output in light of increased work demand
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| - | **EDV is increased by the ejection fraction is below normal.
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| - | **Venous pressure (and therefore atrial pressure) are elevated because of ventricular pressure overload. (That is, venous pressure goes up because the ventricle must reach a higher systolic pressure to get blood through the stenosed valve.)
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| - | **Systolic murmur is audible because the blood turbulantly rushes around the stenosed valve.
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| - | ===IV. Semilunar valve insufficiency===
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| - | *In this situation the valve is causing pressures in the ventricle to be abnormally high.
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| - | *This increase in pressure causes "over-distension".
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| - | **"distention: the act of expanding by pressure from within" per [http://wordnetweb.princeton.edu/perl/webwn wordnet]
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| - | *In this pathology, during systole, blood flows out of the ventricle, through the valve but then some returns to the ventricle during diastole.
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| - | *Recall that work is the stroke volume multiplied by the pressure (W = SV * P)
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| - | *Before we could replace valves, we sometimes knicked stenosed valves with a knife to make them an insufficient valve for which the heart can better compensate.
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| - | *S&S:
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| - | **The ventricular chamber will expand and the ventricle will hypertrophy but not to the extent seen in stenosis.
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| - | **EDV will increase and the ejection fraction will be increased, however, the effective stroke volume that actually stays in the aorta may be below normal.
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| - | **Arterial and venous pressures will rise because ventricular volume overload
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| - | **A diastolic murmur will be heard as the blood moves backward through the valve during diastole.
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| - | ***Like a flag in the wind; constant throughout diastole.
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| - | *stopped here on 01/31/11 at 12PM.
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| - | ===V. Atrioventricular stenosis===
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| - | *In this pathology, blood has difficulty entering the ventricle from the atrium.
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| - | *Recall that work is stroke volume times pressure (W = SV * Pressure)
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| - | *With AV stenosis the ventricle does not fill properly so the EDV is low.
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| - | *S&S:
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| - | **The ventricle may become smaller than normal.
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| - | ***This results because of a low SV and the ventricle being under worked.
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| - | **EDV is decreased by ejection fraction is increased.
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| - | **Atrial and venous pressure are elevated because of AV valve resistance.
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| - | **Diastolic murmur is heard as blood must be forced through the AV valves.
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| - | **3rd and 4th heart sounds may also be heard
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| - | ===VI. Atrioventricular insufficiency===
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| - | *AV insufficiency allows blood to flow backward form the ventricle to the atrium
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| - | *The ventricle ends up being overworked because it has to generate more pressure over a larger volume in order to generate the correct output in spite of the fact that some of its effort is spent on pushing blood back into the atrium.
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| - | *S&S:
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| - | **Ventricular chamber enlarged and hypertrophied
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| - | **EDV is elevated, ejection fraction is elevated, however, the effective stroke volume is decreased
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| - | **Arterial and venous pressure are increased because of back flow from the ventricular systole
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| - | **Systolic murmur can be heard as blood moves into the atrial during ventricular systole (3/4th sound)
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| - | ===Clinical case===
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| - | *45 yo f
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| - | *bicuspid aortic vavle
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| - | *A. Aortic regurgitation
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| - | '''*B. Aortic stenosis'''
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| - | **"A noisey stenotic aortic valve that the lady has compensated with a high vascular resistance"
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| - | *C. Mitral regurgitation
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| - | *D. Mitral stenosis
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| - | *E. Mitral valve prolapse
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| - | ===Clinical case===
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| - | *87 yo f
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| - | *A. loss of papillary muscle function in the right ventricle.
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| - | *'''B. loss of papillary muscle function in the left ventricle.'''
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| - | **"loss of papillary muscle function in the left ventricle. Location of murmur fits plus timing fits."
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| - | *C. a clot obstruction of the aortic valve.
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| - | *D. a clot obstruction of the mitral valve.
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| - | *E. a transmural breakdown of the left ventricular wall infarct.
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