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Valves and Heart Sounds

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Normal heart sounds are heard when
valves are closing, not opening
first heart sound
closure of AV valves at beginning of systole. Caused by the vibration of the blood and ventricle walls.
second heart sound
closure of semilunar sounds at end of systole. Caused by the sudden snap closure
Duration of the 1st and 2nd heart sound
first 0.14 sec - second 0.11
Which has higher frequency and why
Second - taughtness of valve and high elasticity of the arterial walls
third heart sound
faint sound associated with blood flowing into ventricles at the beginning of the middle third of diastole
fourth heart sound
atrial heart sound - faint sound of atrial contraction at ~ the beginning of the 3rd third of diastole caused by rush of blood into ventricles
Chest Surface Areas for Auscultation of Normal Heart Sounds
1-aortic area is upward along the aorta
2-pulmonic area is upward along the pulmonary artery.
3-Tricuspid area is over the right ventricle, 4-Mitral area is over the apex of the left ventricle
Loud and long 1st heart sound and no 2,3 or 4
Aortic stenosis - causes the loudest murmur of all
low and prolonged 1st sound, and no 2,3 or 4
mitral regurgitation
normal 1st and a combined long 2nd, 3rd and 4th
aortic regurgitation
normal 1st and 2nd then an audible 3rd and slightly more audible 4th
mitral stenosis - causes the weakest murmur of all
prolonged and merged 1-4 with 1 being loudest
patent ductus arteriosus
Valvular lesions
Often caused by Rheumatic fever.
Mitral valve receives more trauma so it is often most damaged
aortic valve is second most damaged due to higher pressure
What do the lesions cause?
leaflets become stuck together - stenosed., making them scarred and solid so they do not close = ventricles contract=regurgitation of blood
Heart murmur of Aortic Stenosis
pressure in left ventricle rises to 300-400 mmHg while pressure in aorta is normal. Causes jetting effect of blood during systole=severe turbulence vibrations when blood is ejected and a loud murmur
"thrill"
sound vibrations of aortic stenosis felt with the hand on the upper chest and lower neck, a phenomenon known as a "thrill."
Heart murmur of aortic regurgitation
no murmur in systole. During diastole blood flows backward from high pressure in aorta from turbulence of blood jetting backward into the low pressure ventricle
Heart Murmur of Mitral Regurgitation
blood flows backward through the mitral valve into the left atrium during systole. causing high frequency "blowing," swishing sound in the left atrium.
Heart Murmur of Mitral Stenosis
Blood passes with difficulty through the stenosed mitral valve from the low pressure left atrium into the left ventricle. Lack of high pressure so abnormal sounds are not heard. After partial filling, the ventricle has stretched enough for blood to reverberate, and a low rumbling murmur begins.
What murmurs occur only during systole?
aortic stenosis and mitral regurgitation
What murmurs occur only during diastole
aortic regurgitation and mitral stenosis
In aortic stenosis and aortic regurgitation the net stroke volume output is
reduced
What compensations of the circulation occur in aortic stenosis and aortic regurgitation?
1. Hypertrophy of the left ventricle due to increased ventricular load
2.Increase in blood volume due to slight decrease in arterial pressure plus peripheral circulatory reflexes caused by decreased pressure and red cell mass increases due to slight tissue hypoxia.
What type of heart disease causes the left ventricular mass to increase 4-5X?
Aortic regurgitation
What type of heart disease causes the left intraventricular pressure to rise to as much as 400mmHg in systolic peak?
Aortic stenosis
In the early stages of aortic stenosis and regurgitation what prevents significant abnormalities in the person at rest?
the ability of the left ventricle to adapt to the changes - so person may have little or no symptoms initially while disease progresses
At critical stage of aortic valve lesions what occurs?
left ventricle cannot keep up with demand, dilates, CO falls, blood dams up in left atrium and lungs. Left atrial pressure rises >25-40mmHg causing pulmonary edema
In what type of heart disease is blood flow from the left atrium into the left ventricle impeded?
mitral stenosis
In what heart disease does much of the blood flow in the left ventricle during diastole leak into the left atrium during systole?
mitral regurgitation
The buildup of blood in the left atrium causes progressive increase in left atrial pressure (25 mmHg - 40 mmHg), and this eventually results in
development of serious pulmonary edema.
What causes atrial fibrillation?
An enlarged left atrium due to high left atrial pressure causing enlargement of the left atrium which affects the cardiac electrical pathways leading to circus movements causing atrial fibrillation
What are the Compensations in Early Mitral Valvular Disease?
1. Blood volume increases due to diminished excretion of water and salt by the kidneys=increases venous return to the heart
2. increase in atrial pressure, blood damming in lungs all the way to pulmonary artery. Edema causes pulmonary-arteriolar constriction. All combined cause increased pressure and hypertrophy of the right heart which compensates for increased load.
Effects of exercise in patients with aortic valvular lesions
acute left ventricular failure followed by acute pulmonary edema.
Effects of exercise in patients with mitral disease
damming of blood in the lungs that serious or lethal pulmonary edema may occur in as little as 10 minutes.
Three major types of congenital anomalies of the heart and its associated vessels:
1. stenosis
2. left-to-right shunt - Patent Ductus Arteriosus
3. right-to-left shunt
4. coarctation of the aorta
coarctation of the aorta causes
arterial pressure in the upper body to be much greater than the lower body - must use collateral vessels
Ductus Arteriosus
pulmonary pressure is high, aortic pressure is low, blood shunts
Ductus Arteriosus after birth
lungs inflate, pressure in pulmonary artery falls and pressure in aorta rises. Blood begins to flow backward through the ductus from the aorta into the pulmonary artery. Ductus occludes and becomes ligamentum arteriosum.
Patent Ductus Arteriosus-steps in disease
Remains open. 1. As child grows pressure in aorta increases and pressure in pulmonary decreases further. Blood back flows from aorta to pulmonary. Over time the high aortic pressure makes opening larger and condition worsens. 2. 2x through lungs for every 1x in systemic-arterial blood more O2 than normal
Major effects of patent ductus arteriosus are
1. decreased cardiac and respiratory reserve due to lower net blood flow thru body
2. high pulmonary pressure due to excess flow thru lungs->pulmonary congestion->pulmonary edema
machinery murmur
the murmur of patent ductus arteriosus load 1st and merged 2-4 but less loud
Tetraology of Fallot
overrding of the aorta
pulmonary stenosis
VSD
enlarged right ventricle causing boot shaped heart - left ventricle extends out
Pentalogy of Fallot
Tetralogy of Fallot plus an atrial septal defect or patent foramen ovale
What is the abnormal circulation in Tetraology of Fallot?
75% of venous blood passes from right ventricle to aorta without getting oxygenated
Signs of Tetraology of Fallot
cyanosis
high systolic pressure in the right ventricle
enlarged right ventricle
angiogram showing abnormal blood flow through septum and in overriding aorta
One of the most common causes of congenital anomalies
Rubella