Guyton and Hall Physiology Chapter 23 - Heart Valves and Heart Sounds
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Guyton and Hall Physiology Chapter 23 - Heart Valves and Heart Sounds

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Questions and Answers

What characterizes the machinery murmur heard in the pulmonary artery area as a baby grows older?

  • It is much more intense during systole. (correct)
  • It increases in intensity during diastole.
  • It is absent in infants with PDA.
  • It is continuous and does not vary with the heartbeat.

    • Which procedure is often performed to treat patent ductus arteriosus (PDA)?

  • Transposition of the great vessels.
  • Truncation of the aorta.
  • Insertion of a stent within the aorta.
  • Ligation or division of the patent ductus. (correct)

    • What is a common symptom of Tetralogy of Fallot that indicates the presence of unoxygenated blood in the aorta?

  • Increased heart rate and output.
  • Murmurs that are consistent in all heart phases.
  • Enlargement of the left ventricle.
  • Cyanosis of the skin. (correct)

    • During what phase of the cardiac cycle is the murmur from PDA most intense?

    <p>Systole when aortic pressure is high.</p> Signup and view all the answers

    What condition can result from the right-to-left shunt seen in Tetralogy of Fallot?

    <p>Right ventricular hypertrophy.</p> Signup and view all the answers

    What is a significant risk factor for children of patients who have had congenital heart disease?

    <p>They have a 10 times greater chance of developing heart disease.</p> Signup and view all the answers

    Why does tetralogy result in major physiological difficulties?

    <p>The muscle hypertrophies without improving blood flow.</p> Signup and view all the answers

    What complication is commonly associated with cardiac hypertrophy?

    <p>Development of myocardial fibrosis.</p> Signup and view all the answers

    What is the primary function of extracorporeal circulation during cardiac surgery?

    <p>To take over the function of the heart and lungs.</p> Signup and view all the answers

    Why might patients with valvular or congenital heart disease experience anginal pain?

    <p>As a result of coronary blood flow insufficiency.</p> Signup and view all the answers

    What issue commonly arises from the disproportionate increase in cardiac muscle mass?

    <p>Development of cardiac arrhythmias.</p> Signup and view all the answers

    How does congenital heart disease typically affect systemic health?

    <p>It is often linked with other congenital defects in the body.</p> Signup and view all the answers

    What is the main component of the extracorporeal circulation system used during cardiac surgery?

    <p>A pump and an oxygenating device.</p> Signup and view all the answers

    What is the effect of successful surgery on the life expectancy of patients with the described heart condition?

    <p>Increases to 50 or more years</p> Signup and view all the answers

    What does fibrosis in the subendocardial muscle commonly indicate?

    <p>Replacement of degenerating muscle fibers with fibrous tissue.</p> Signup and view all the answers

    What happens to the pulmonary artery in this heart condition?

    <p>It is stenosed, leading to reduced blood flow to the lungs.</p> Signup and view all the answers

    Which of the following describes blood flow dynamics in this heart defect?

    <p>Blood from both ventricles can directly enter the aorta due to septal defects.</p> Signup and view all the answers

    What is known to occur in identical twins regarding congenital heart defects?

    <p>The same defect can occur in both twins.</p> Signup and view all the answers

    What is the primary risk associated with the mother contracting German measles during the first trimester of pregnancy?

    <p>It can lead to congenital heart defects in the developing fetus.</p> Signup and view all the answers

    Which of the following medications is associated with an increased risk of congenital heart defects?

    <p>Angiotensin-converting enzyme (ACE) inhibitors</p> Signup and view all the answers

    What anatomical feature forms due to the right ventricle's adaptation to high pressure in this condition?

    <p>Hypertrophy of the right ventricle musculature</p> Signup and view all the answers

    How does blood typically bypass the lungs in this congenital heart defect?

    <p>By being redirected through the septal defect into the aorta</p> Signup and view all the answers

    What percentage of live births is affected by congenital heart disease?

    <p>8 of every 1000 live births</p> Signup and view all the answers

    What is a consequence of rising left atrial pressure?

    <p>Diminished cardiac output</p> Signup and view all the answers

    What effect does coarctation of the aorta have on blood pressure in the body?

    <p>Higher pressure in the upper body compared to the lower body</p> Signup and view all the answers

    What physiological change is associated with increased systolic pulmonary arterial pressure?

    <p>Hypertrophy of the right side of the heart</p> Signup and view all the answers

    What is the typical blood flow change through the ductus arteriosus at birth?

    <p>Blood flows backward from the aorta into the pulmonary artery</p> Signup and view all the answers

    What occurs as a result of pulmonary arteriolar constriction due to lung edema?

    <p>Elevated right ventricular pressure</p> Signup and view all the answers

    What is a common outcome of congenital stenosis in cardiac function?

    <p>Development of collateral circulation</p> Signup and view all the answers

    How does increased left atrial pressure contribute to pulmonary edema?

    <p>By causing blood to back up into the lungs</p> Signup and view all the answers

    What is the relationship between right ventricular pressure and the workload experienced during coarctation of the aorta?

    <p>Right ventricular pressure increases to compensate for the workload</p> Signup and view all the answers

    What compensatory mechanism involves blood bypassing the coarctation in aorta?

    <p>Formation of collateral arteries</p> Signup and view all the answers

    What is the primary driving factor for the backward blood flow through the ductus arteriosus after birth?

    <p>Increased systemic arterial pressure</p> Signup and view all the answers

    What is a common complication in the late stages of mitral valvular disease?

    <p>Atrial fibrillation</p> Signup and view all the answers

    Which of the following describes a left-to-right shunt?

    <p>Blood flowing backward from the left side to the right side of the heart</p> Signup and view all the answers

    What primarily causes the increased blood volume in mitral valvular disease?

    <p>Diminished excretion of water and salt by the kidneys</p> Signup and view all the answers

    Which type of congenital anomaly results from blood flowing from the right side to the left side of the heart?

    <p>Right-to-left shunt</p> Signup and view all the answers

    What is the effect of increased left atrial pressure in late mitral valvular disease?

    <p>Minimal impact on cardiac output</p> Signup and view all the answers

    Which statement is true about congenital heart defects?

    <p>Stenosis is a common type of congenital anomaly</p> Signup and view all the answers

    What may lead to excitatory signal circus movements in abnormal circulatory dynamics?

    <p>Prolonged pathways in the heart</p> Signup and view all the answers

    What is one of the primary effects of congenital aortic valve stenosis?

    <p>Dynamic effects similar to aortic valve stenosis</p> Signup and view all the answers

    What compensatory mechanism occurs in early mitral valvular disease?

    <p>Increased venous return to the heart</p> Signup and view all the answers

    How does mitral stenosis primarily affect cardiac function?

    <p>It reduces the pumping effectiveness of the heart</p> Signup and view all the answers

    The first heart sound is associated with the closure of the aortic and pulmonary valves.

    <p>False</p> Signup and view all the answers

    The second heart sound results from the closing of the atrioventricular valves.

    <p>False</p> Signup and view all the answers

    Heart sounds can be described as 'lub, dub, lub, dub' when listening to a normal heart with a stethoscope.

    <p>True</p> Signup and view all the answers

    Audible sounds occur when the heart valves open.

    <p>False</p> Signup and view all the answers

    The vibrations created by the heart sounds are transmitted primarily along the arteries.

    <p>True</p> Signup and view all the answers

    The closure of the semilunar valves causes blood to bulge backward towards the ventricles.

    <p>True</p> Signup and view all the answers

    Heart sounds are never detectable using medical instruments.

    <p>False</p> Signup and view all the answers

    The 'dub' sound is associated with the heart's systolic phase.

    <p>False</p> Signup and view all the answers

    The third heart sound is generally present in older adults and indicates good cardiac health.

    <p>False</p> Signup and view all the answers

    A fourth heart sound can often be recorded in the phonocardiogram from most individuals.

    <p>False</p> Signup and view all the answers

    The atrial heart sound can be easily heard using a standard stethoscope.

    <p>False</p> Signup and view all the answers

    The third heart sound is produced by vibrations from blood flowing into the atria.

    <p>False</p> Signup and view all the answers

    Hypertrophy of the left ventricle often leads to the presence of a fourth heart sound.

    <p>True</p> Signup and view all the answers

    An increase in resistance to ventricular filling can cause a decrease in the third heart sound.

    <p>True</p> Signup and view all the answers

    The phonocardiogram is used to amplify heart sounds for medical recordings.

    <p>True</p> Signup and view all the answers

    Atrial contraction causes vibrations similar to those of the fourth heart sound.

    <p>False</p> Signup and view all the answers

    The frequency of the atrial heart sound is typically above 20 cycles/sec.

    <p>False</p> Signup and view all the answers

    In children and adolescents, the third heart sound is usually associated with heart disease.

    <p>False</p> Signup and view all the answers

    Congenital heart disease occurs in about 8 of every 100 live births.

    <p>False</p> Signup and view all the answers

    The aorta can originate from the right ventricle rather than the left in certain heart conditions.

    <p>True</p> Signup and view all the answers

    Taking angiotensin-converting enzyme (ACE) inhibitors during pregnancy decreases the risk of congenital heart defects.

    <p>False</p> Signup and view all the answers

    When surgery for congenital heart defects is successful, the average life expectancy can increase to over 50 years.

    <p>True</p> Signup and view all the answers

    The pulmonary artery is typically stenosed in congenital heart conditions leading to higher blood flow to the lungs.

    <p>False</p> Signup and view all the answers

    Aortic valve stenosis is often referred to as senile calcific aortic valve stenosis due to calcium deposition with aging.

    <p>True</p> Signup and view all the answers

    Rheumatic fever is caused by a viral infection from a group B streptococcus.

    <p>False</p> Signup and view all the answers

    Left ventricular concentric hypertrophy occurs as a compensatory response to the increased workload from a stenotic aortic valve.

    <p>True</p> Signup and view all the answers

    The pressure gradient across a stenotic aortic valve can reach up to 150 mm Hg in severe cases.

    <p>False</p> Signup and view all the answers

    Aortic valve stenosis is one of the least common heart valve diseases due to aging populations.

    <p>False</p> Signup and view all the answers

    The antibodies produced in response to streptococcal infection can accidentally damage the body's own tissues.

    <p>True</p> Signup and view all the answers

    Calcium deposition in aortic stenosis leads to an enlarged aortic valve opening.

    <p>False</p> Signup and view all the answers

    Immunologic damage due to rheumatic fever primarily affects the liver.

    <p>False</p> Signup and view all the answers

    Streptococcal infections can only cause respiratory issues such as a sore throat.

    <p>False</p> Signup and view all the answers

    Calcification of heart valves is a result of normal aging processes.

    <p>True</p> Signup and view all the answers

    The ductus arteriosus is believed to close due to the increasing oxygen concentration in the blood flowing through it.

    <p>True</p> Signup and view all the answers

    Patent ductus arteriosus affects 1 in every 1500 babies.

    <p>False</p> Signup and view all the answers

    The pressure in the pulmonary artery is higher than the pressure in the aorta in a healthy infant.

    <p>False</p> Signup and view all the answers

    As a child with patent ductus arteriosus grows older, the backward flow of blood from the aorta into the pulmonary artery typically decreases.

    <p>False</p> Signup and view all the answers

    During the early months, a patent ductus does not usually cause severely abnormal function.

    <p>True</p> Signup and view all the answers

    Oxygenated blood from the aorta flows backwards into the pulmonary artery in cases of patent ductus arteriosus.

    <p>True</p> Signup and view all the answers

    The phenomenon of the ductus closing is effectively irrelevant to the function of the heart after birth.

    <p>False</p> Signup and view all the answers

    In a healthy circulatory system, blood typically changes from oxygenated to venous blood at the same points.

    <p>False</p> Signup and view all the answers

    As the differential pressure between the aorta and pulmonary artery increases, it can lead to complications in patients with patent ductus arteriosus.

    <p>True</p> Signup and view all the answers

    Venous blood is depicted as blue in diagrams representing patent ductus arteriosus.

    <p>True</p> Signup and view all the answers

    Match the heart sounds with their associated events:

    <p>First heart sound = Closure of A-V valves Second heart sound = Closure of semilunar valves A-V valves = Prevent backflow into the atria Semilunar valves = Prevent backflow into the ventricles</p> Signup and view all the answers

    Match the characteristics with the corresponding heart sounds:

    <p>First heart sound = Louder and longer sound Second heart sound = Shorter and higher frequency Frequency range = 40 to 500 cycles/sec Components = Vibration of heart walls</p> Signup and view all the answers

    Match the heart sound descriptions with the correct frequencies:

    <p>20 cycles/sec = Peak frequency of recorded sound 40 cycles/sec = Lowest frequency the ear can detect 500 cycles/sec = High frequency sound range 3 to 4 cycles/sec = Lowest detectable frequency electronically</p> Signup and view all the answers

    Match the reasons for heart sound differences:

    <p>Longer first sound = A-V valves vibrating longer Shorter second sound = Tautness of semilunar valves First sound generation = Backflow against A-V valves Second sound frequency = Higher than first sound</p> Signup and view all the answers

    Match the terms with their meanings related to heart sounds:

    <p>Phonocardiography = Recording heart sounds electronically Heart turbulence = Vibration of blood and walls Chordae tendineae = Prevent valves from bulging back Audible range = Range of frequencies detectable by the ear</p> Signup and view all the answers

    Match the following conditions with their associated effects on the heart:

    <p>Aortic Stenosis = Increased intraventricular pressure Aortic Regurgitation = Decreased aortic diastolic pressure Chronic Hypertension = Increased afterload on the heart Ischemia = Reduced coronary blood flow</p> Signup and view all the answers

    Match the following mechanisms with their descriptions:

    <p>Increased Blood Volume = Compensation for diminished net pumping Thickened Ventricular Walls = Concentric hypertrophy Nervous Reflexes = Induced by decreased arterial pressure Stroke Volume Output = Can be as great as 250 milliliters in regurgitation</p> Signup and view all the answers

    Match the following heart conditions with their complications:

    <p>Aortic Stenosis = Compression of inner heart muscle layers Aortic Regurgitation = Increased stroke volume returning to ventricle Severe Aortic Stenosis = Myocardial ischemia Pulmonary Edema = Failure of Left Ventricle</p> Signup and view all the answers

    Match the following statements with their implications:

    <p>Intravenous Pressure Increases = Causes myocardial ischemia Diminished Coronary Blood Flow = Results from increased pressures Left Ventricular Adaptation = Prevents significant circulatory function abnormalities during rest Decreased Arterial Pressure = Triggers hormonal changes and reflexes</p> Signup and view all the answers

    Match the following effects with their corresponding heart conditions:

    <p>Aortic Regurgitation = 75% of stroke volume returns to ventricle Aortic Stenosis = 400 mm Hg intraventricular pressure at peak Chronic Hypertension = Increased afterload and ventricular adaptation Increased Diastolic Pressure = Compresses inner heart muscle layers</p> Signup and view all the answers

    Study Notes

    Tetralogy of Fallot

    • Four heart abnormalities occur simultaneously:

      • Aorta originates from the right ventricle instead of the left ventricle
      • Pulmonary artery stenosis causes decreased blood flow from the right ventricle to the lungs
      • Blood flows from the left ventricle through a ventricular septal hole into the right ventricle and then into the aorta
      • Enlarged right ventricle due to pumping against high pressure in the aorta

    • Tetralogy of Fallot often leads to cyanosis (blue coloration) in babies

    • Most of the venous blood bypasses the lungs and is shunted directly into the aorta, leading to unoxygenated blood.

    Surgical Treatment

    • Surgical procedure involves:
      • Opening the pulmonary stenosis
      • Closing the septal defect
      • Reconstructing the flow pathway into the aorta
    • Surgical treatment is effective in increasing life expectancy from 3-4 years to 50+ years.

    Causes of Congenital Anomalies

    • Congenital heart disease occurs in about 8 out of every 1000 live births
    • Common causes include maternal viral infections, particularly German measles during the first trimester
    • Certain medications like ACE inhibitors and isotretinoin, alcohol or drug abuse during pregnancy can increase risk
    • Some defects are hereditary.

    Extracorporeal Circulation During Cardiac Surgery

    • Extracorporeal circulation (heart-lung machines) is used during cardiac surgery to take over the function of the heart and lungs
    • This system consists of a pump and an oxygenating device
    • This is necessary because it’s almost impossible to repair intracardiac defects while the heart is beating.

    Abnormal Circulatory Dynamics in Congenital Heart Defects

    • Stenosis: Narrowing of a blood flow channel in the heart or major blood vessels
    • Left-to-right shunt: Abnormal blood flow from the left side of the heart or aorta to the right side of the heart or pulmonary artery, bypassing systemic circulation
    • Right-to-left shunt: Abnormal blood flow from the right side of the heart directly into the left side of the heart, bypassing the lungs

    Heart Muscle Hypertrophy

    • Enlargement of the heart muscle due to pressure overload, often associated with valvular and congenital heart disease.
    • Can lead to:
      • Ischemia due to disproportionate muscle growth compared to coronary blood flow
      • Angina
      • Arrhythmias
      • Increased risk of sudden death from fibrillation

    Coarctation of the Aorta

    • Narrowing of the aorta, often above the diaphragm
    • Causes higher blood pressure in the upper body compared to the lower body
    • Blood flow to the lower body is affected, requiring circulation through smaller collateral arteries

    Patent Ductus Arteriosus (PDA)

    • Open ductus arteriosus (a blood vessel connecting the aorta and pulmonary artery in the fetus) remaining open after birth
    • Often closes within a few hours or days after birth
    • Can lead to a "machinery murmur" in the pulmonary artery area
    • Surgical treatment involves ligation (tying off) or division of the PDA.
      • Catheter-based devices are often used for larger infants and children.

    Heart Sounds

    • The first heart sound ("lub") is associated with the closure of the atrioventricular (A-V) valves at the beginning of systole.
    • The second heart sound ("dub") is associated with the closure of the semilunar (aortic and pulmonary) valves at the end of systole.
    • The third heart sound can be normal in children and young adults but usually indicates systolic heart failure in older adults.
    • The fourth heart sound is rarely heard with a stethoscope but can be recorded with a phonocardiogram.
    • The fourth heart sound occurs when atria contract, caused by the inrush of blood into the ventricles.

    Valvular Lesions

    • Rheumatic fever, an autoimmune disease, can damage or destroy heart valves.
    • Rheumatic fever is often triggered by a streptococcal infection.
    • Senile calcific aortic valve stenosis is characterized by valve calcium deposition and ossification, leading to narrowing of the aortic valve orifice.

    Congenital Heart Defects

    • Congenital heart defects occur in approximately 8 out of every 1000 live births.
    • A viral infection in the mother during the first trimester of pregnancy is a common cause of congenital heart defects.
    • German measles (rubella) contracted by the mother during the first trimester of pregnancy significantly increases the risk for heart defects in the developing fetus.
    • Other risk factors for congenital heart defects include certain medications, alcohol or drug abuse during pregnancy.

    Tetralogy of Fallot

    • Tetralogy of Fallot is a complex congenital heart defect involving four simultaneous abnormalities:
      • The aorta originates from the right ventricle rather than the left and overrides a hole in the septum.
      • The pulmonary artery is stenosed, limiting blood flow from the right ventricle to the lungs.
      • Blood from the left ventricle flows through a ventricular septal hole into the right ventricle.
      • The right ventricle is enlarged due to pumping blood against high pressure.
    • Tetralogy of Fallot can be successfully treated with surgery.

    Patent Ductus Arteriosus

    • The ductus arteriosus is a blood vessel connecting the aorta to the pulmonary artery in the fetal circulation.
    • The ductus arteriosus usually closes shortly after birth due to the increased oxygen concentration in the aorta, constricting the muscle in the ductus wall.
    • Patent ductus arteriosus occurs when the ductus does not close, causing backflow of blood from the aorta into the pulmonary artery.
    • A patent ductus arteriosus can usually be successfully treated with surgery.

    Heart Sounds

    • The first heart sound, "lub", is about 0.14 seconds long and caused by the closure of the A-V valves (tricuspid and mitral valves) at the onset of ventricular systole
    • The second heart sound, "dub", is about 0.11 seconds long and caused by the closure of the semilunar valves (aortic and pulmonary valves)
    • The duration of the second heart sound is shorter due to the semilunar valves being tauter than the A-V valves
    • The frequency of the heart sounds ranges from 40 to 500 cycles/sec, but a larger portion of sound is below the audible range and can be recorded electronically by phonocardiography

    Aortic Stenosis

    • Aortic valve stenosis refers to a narrowing of the aortic valve, restricting blood flow from the left ventricle to the aorta
    • It can lead to an increase in intraventricular diastolic pressure, potentially compressing inner layers of the heart muscle and reducing coronary blood flow
    • Severe aortic stenosis can cause ischemia of the heart muscle due to reduced blood flow to the heart tissue

    Aortic Regurgitation

    • Aortic regurgitation is a backflow of blood from the aorta into the left ventricle during diastole
    • It also causes an increase in intraventricular diastolic pressure, potentially compressing inner layers of the heart muscle and reducing coronary blood flow
    • Aortic diastolic pressure decreases in aortic regurgitation, further contributing to the reduced coronary blood flow and potential ischemia

    Left Ventricular Failure and Pulmonary Edema

    • In the early stages of aortic valve stenosis or regurgitation, the left ventricle can adapt to increased loads, preventing significant circulatory dysfunction during rest
    • However, these conditions can eventually lead to left ventricular failure, causing a decline in cardiac output and the development of pulmonary edema
    • Pulmonary edema develops due to the failure of the left ventricle to effectively pump blood, leading to fluid buildup in the lungs

    Mitral Valvular Disease

    • Mitral valvular disease refers to conditions affecting the mitral valve, including mitral stenosis, narrowing of the mitral valve, and mitral regurgitation, backflow of blood from the left ventricle to the left atrium
    • In the early stages, the heart compensates for the mitral valvular disease by increasing blood volume, potentially reducing renal excretion of water and salt
    • This increased blood volume improves venous return to the heart, mitigating the effects of cardiac debility
    • However, in late stages, atrial fibrillation can occur, further reducing cardiac pumping effectiveness and exacerbating cardiac debility

    Congenital Heart Defects

    • Congenital anomalies of the heart refer to malformations that occur during fetal development
    • Three major types include: stenosis, narrowing of blood flow channels, left-­to-­right shunt, blood flow from the left side of the heart to the right side, and right-­to-­left shunt, blood flow from the right side of the heart to the left side
    • Some congenital defects, like aortic valve stenosis, mimic the effects of acquired conditions
    • Some congenital heart defects are hereditary and can be found in twins and succeeding generations

    Cardiac Hypertrophy

    • Cardiac hypertrophy is an enlargement of the heart muscle, often occurring in response to increased workload
    • It can be caused by valvular and congenital heart diseases, resulting in increased pressure against which the heart muscle must contract
    • Cardiac hypertrophy can lead to detrimental effects, including relative ischemia, increased susceptibility to arrhythmias, and sudden death due to fibrillation

    Extracorporeal Circulation

    • Extracorporeal circulation is used during cardiac surgery to replace the function of the heart and lungs
    • It consists of a pump and an oxygenating device that circulate blood outside the body, allowing for open-heart surgery

    References

    • J Am Coll Cardiol 71:2058, 2018
    • Circ Res 113:223, 2013
    • JAMA 310:1490, 2013
    • N Engl J Med 379:655, 2018
    • J Am Coll Cardiol 73:1978, 2019
    • Circulation 135:e1159, 2017
    • Curr Cardiol Rev 14:264, 2018
    • Lancet 387:1335, 2016

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    Description

    This quiz covers the key aspects of Tetralogy of Fallot, including its four heart abnormalities and the associated surgical treatments. Understand how these congenital heart defects lead to symptoms like cyanosis and learn about the effectiveness of surgical intervention in improving life expectancy.

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