Introduction to Heart Sounds

The correct answer is point "E." The clinical vignette describes a patient with signs and symptoms suggestive of heart failure, and the low-frequency diastolic heart sound heard shortly after the second heart sound (S2) when the patient lies in the left lateral decubitus position is most consistent with an S3 gallop. The S3 heart sound is associated with the rapid filling phase of the ventricles during early diastole and is often a sign of heart failure or ventricular volume overload. It is best heard when the patient lies in the left lateral decubitus position. On a cardiac pressure-volume loop, the S3 heart sound would occur near the point of the lowest pressure following the end-systolic pressure point as the ventricles begin to fill (Point E). This corresponds to the initial downward slope where the volume starts to increase during diastole but before the atrial contraction (point F). Point A. Mitral Va

A 65-year-old woman comes to the physician complaining of weakness, exertional dyspnea, orthopnea, and increasing fatigue. She has shortness of breath at night and has been sleeping in a recliner to help relieve his dyspnea. On cardiac auscultation, a low-frequency diastolic heart sound is heard shortly after the second heart sound when the patient lies in the left lateral decubitus position. This heart sound most likely occurs in this patient nearest to which of the following points on the cardiac pressure-volume loop? D F C E A B

The correct answer is: "An S4 heart sound cannot occur in atrial fibrillation because the atria do not contract effectively." The S4 heart sound, also known as an atrial gallop, occurs just before the first heart sound (S1) and is associated with atrial contraction pushing blood into a stiff or non-compliant ventricle. However, effective atrial contraction is lost in atrial fibrillation due to the chaotic electrical activity of the atria. Therefore, the physiological basis for generating an S4 sound, which relies on atrial contraction, is absent in patients with atrial fibrillation. This makes the presence of an S4 heart sound highly unlikely in atrial fibrillation. Commonly observed in patients with atrial fibrillation due to the increased atrial contraction strength. This statement is incorrect because, in atrial fibrillation, the atrial contractions are not strong or coordinated but rather are rapid and irregu

Question 10 1 / 1 pts A 68-year-old man with a history of chronic hypertension and a recent diagnosis of atrial fibrillation presents to his cardiologist for a follow-up visit. He is currently on anticoagulation therapy and medication for blood pressure control. During auscultation, the cardiologist focuses on identifying additional heart sounds that may indicate underlying cardiac pathology. Which of the following statements is most accurate regarding the presence of an S4 heart sound in this patient? An S4 heart sound is commonly observed in patients with atrial fibrillation due to the increased atrial contraction strength. The S4 heart sound in atrial fibrillation is a direct result of rapid ventricular filling during the diastolic phase. An S4 heart sound cannot occur in atrial fibrillation because the atria do not contract effectively. Atrial fibrillation enhances the audibility of the S4 heart sound due to irregular ventricular filling times. The presence of an S4 heart sound is indicative of improved atrial compliance and is a positive prognostic indicator in atrial fibrillation.

The correct answer is: "Closure of the mitral and tricuspid valves." The first heart sound (S1) is primarily produced by the closure of the mitral and tricuspid valves at the beginning of ventricular systole during the isovolumetric contraction phase. This sound marks the onset of ventricular contraction and the end of diastole. This closure prevents the backflow of blood into the atria, contributing to the "lub" sound in the "lub-dub" pattern heard during cardiac auscultation. Closure of the aortic and pulmonary valves. This option refers to the event that generates the second heart sound (S2), not S1. S2 occurs at the beginning of ventricular diastole (during the isovolumetric relaxation period) when the aortic and pulmonary valves close to prevent blood from flowing back into the ventricles from the aorta and pulmonary artery, respectively. Rapid ventricular filling. Rapid ventricular filling occurs during th

Question 2 1 / 1 pts A 25-year-old man comes to the physician for a routine health examination. On auscultation, the first heart sound (S1) is noted to be loud. Which of the following best explains the physiological mechanism of the S1 heart sound? Increased velocity of blood ejection during systole Decreased ventricular compliance Closure of the aortic and pulmonary valves Rapid ventricular filling Closure of the mitral and tricuspid valves

The correct answer is: "Is produced by the closure of the aortic and pulmonary valves at the beginning of ventricular diastole." The second heart sound occurs when the aortic and pulmonary valves close to prevent backflow of blood into the ventricles after ventricular ejection has taken place, marking the end of systole and the beginning of diastole. This closure generates the "dub" sound in the "lub-dub" pattern that is characteristic of heart sounds heard during auscultation. Results from the closure of the mitral and tricuspid valves at the onset of systole. This describes the physiological basis of the first heart sound (S1), not S2. S1 is produced when the mitral and tricuspid valves close to prevent the backflow of blood from the ventricles into the atria as the ventricles begin to contract at the start of systole (isovolumetric contraction phase). Occurs due to turbulent blood flow through the semilunar v

Question 3 1 / 1 pts During a cardiology rotation, a medical student is asked about the physiological basis of the second heart sound (S2). Which of the following is the most accurate description? Reflects rapid ventricular filling during early diastole Is caused by ventricular contraction and ejection of blood Is produced by the closure of the aortic and pulmonary valves at the beginning of ventricular diastole Occurs due to turbulent blood flow through the semilunar valves Results from the closure of the mitral and tricuspid valves at the onset of systole

The correct answer is: "Third heart sound or S3." S3 is a low-pitched sound heard in the early phase of diastole, immediately after the second heart sound (S2), during rapid ventricular filling. It is best heard with the bell of the stethoscope placed on the chest, particularly in the mitral listening area. In adults, particularly those over the age of 40, the presence of an S3 can indicate heart failure or volume overload states, reflecting decreased ventricular compliance. First heart sound or S1. The first heart sound (S1) occurs at the onset of ventricular systole (during the isovolumetric contraction phase) and is associated with the closure of the mitral and tricuspid valves. It is not the low-pitched sound heard immediately after S2 in diastole; therefore, it does not match the description given. Second heart sound or S2. The second heart sound (S2) is produced by the closure of the aortic and pulmonar

Question 4 1 / 1 pts A 55-year-old woman with a history of heart failure presents to the clinic complaining of worsening shortness of breath. On examination, a low-pitched sound is heard immediately after S2 during diastole. This sound is best heard with the bell of the stethoscope. This heart sound most likely represents which of the following? Third heart sound or S3 Second heart sound or S2 First heart sound or S1 Fourth heart sound or S4

The correct answer is: "Left ventricular hypertrophy." The description provided is characteristic of the fourth heart sound (S4). S4 is a soft, low-frequency sound heard just before the first heart sound (S1), particularly in conditions with increased ventricular filling resistance during atrial contraction. This sound is best appreciated at the apex with the patient in the left lateral decubitus position. The presence of an S4 heart sound is most indicative of left ventricular hypertrophy, which is commonly seen in patients with longstanding hypertension. Mitral Regurgitation. Mitral regurgitation is characterized by a systolic murmur due to the backflow of blood from the left ventricle into the left atrium during ventricular systole. It does not produce a discrete sound just before S1, which is when the fourth heart sound (S4) occurs, related to conditions affecting ventricular compliance. Atrial Fibrillation.

Question 5 1 / 1 pts A 60-year-old man with hypertension presents for a follow-up visit. A soft, low-frequency sound is heard just before S1 on cardiac auscultation. This sound is best appreciated at the apex with the patient in the left lateral decubitus position. Which underlying condition is the presence of this heart sound most indicative of? Atrial fibrillation Mitral regurgitation Aortic regurgitation Left ventricular hypertrophy Ventricular septal defect

The correct answer is: "Delayed closure of the pulmonary valve compared to the aortic valve due to increased right ventricular ejection time." Physiological splitting of S2 occurs because the closure of the pulmonary valve is slightly delayed compared to the closure of the aortic valve. This is primarily due to the lower pressure in the pulmonary circulation, which leads to a longer ejection time for the right ventricle. The difference in closure times becomes more pronounced during inspiration, when venous return to the right side of the heart increases, further delaying pulmonary valve closure and enhancing the splitting of S2. Delayed closure of the mitral valve compared to the tricuspid valve. This option does not pertain to the splitting of S2, as the mitral and tricuspid valves are involved in the production of the first heart sound (S1), not S2. S1 occurs at the beginning of systole with the closure of

Question 6 1 / 1 pts Which of the following best explains the physiological mechanism behind the normal splitting of the second heart sound (S2)? Simultaneous closure of the aortic and pulmonary valves Delayed closure of the aortic valve compared to the pulmonary valve due to increased left ventricular ejection time Delayed closure of the pulmonary valve compared to the aortic valve due to increased right ventricular ejection time Early closure of the mitral and tricuspid valves before the aortic and pulmonary valves Delayed closure of the mitral valve compared to the tricuspid valve

The correct answer is: "Fixed splitting of S2." An atrial septal defect (ASD) is a congenital heart defect that allows blood to flow between the left and right atria due to an opening in the interatrial septum. Fixed splitting of S2 occurs because the atrial septal defect causes a constant left-to-right shunt, increasing blood flow to the right side of the heart. This increased flow prolongs the right ventricular systole, causing the pulmonary valve to close later than normal throughout the respiratory cycle. Unlike normal or physiological splitting, which varies with respiration, the splitting of S2 in ASD patients does not vary significantly with inspiration and expiration. Hence, it is described as "fixed." Paradoxical splitting of S2. Paradoxical splitting of S2 occurs when the normal order of valve closure is reversed, with the pulmonary valve closing before the aortic valve. This is usually observed in c

Question 7 1 / 1 pts A 30-year-old woman is diagnosed with an atrial septal defect. Which of the following auscultatory findings is most likely associated with this condition? Physiological splitting of S2 Wide but variable splitting of S2 Paradoxical splitting of S2 Fixed splitting of S2 No splitting of S2

The correct answer is point "B." The physiological splitting of the second heart sound (S2) is best heard at the second left intercostal space, close to the sternum. This area is indicated in the image by the point B. This area is known as the pulmonary area because it is where the sounds from the pulmonary valve are best auscultated. The S2 splitting is due to the aortic valve closing slightly before the pulmonary valve during inspiration, which is best appreciated in this location. Option A. Aortic area, located in the second right intercostal space at the right sternal border. S2 is usually most prominent at this location because it is closest to the aortic valve. This is also where you would listen for aortic stenosis and regurgitation murmurs. Point C. The tricuspid area is in the fifth intercostal space at the lower left sternal border. This is where you would listen for murmurs associated with the tric

Question 8 1 / 1 pts In the image below, in which of the following areas is the physiological splitting of the second heart sound (S2) best heard during heart auscultation? A C B D

The correct answer is: "During atrial systole, correlating with the P wave." An S4 heart sound, also known as an atrial gallop, occurs just before the first heart sound (S1) and is typically associated with the atria contracting against a stiff or non-compliant ventricle. It is often present in conditions that lead to increased resistance to ventricular filling, such as left ventricular hypertrophy, which is a common consequence of longstanding hypertension. The S4 sound is caused by the blood being forced into the ventricle during atrial systole, which corresponds to the P wave on the EKG, indicating atrial depolarization. The left atrial enlargement on the EKG supports the presence of an S4 sound, as it suggests that the atrium is working harder to overcome the increased ventricular stiffness. During ventricular systole, correlating with the QRS complex. This choice is incorrect because the S4 sound occurs b

Question 9 1 / 1 pts A 50-year-old male presents with a history of chest pressure and shortness of breath on exertion. His electrocardiogram (EKG) shows signs of left ventricular hypertrophy. Upon examination, his blood pressure was 170/100 mm Hg. Auscultation reveals a loud S4 heart sound. The EKG also demonstrates a left atrial enlargement pattern. When in the cardiac cycle does the S4 heart sound typically occur, and how does this correlate with the findings on the EKG? During rapid ventricular filling, correlating with the T wave At the onset of ventricular diastole, correlating with the PR interval During ventricular systole, correlating with the QRS complex During atrial systole, correlating with the P wave During isovolumetric relaxation, correlating with the ST segment