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Heart Sounds

Heart sounds are brief, transient sounds produced by valve opening and closure and by movement of blood in the heart. They are divided into systolic and diastolic sounds. In most cases, only the first (S1) and second (S2) heart sounds are heard. These are high-frequency sounds and arise from mitral and tricuspid valve Tricuspid valve The valve consisting of three cusps situated between the right atrium and right ventricle of the heart. Heart: Anatomy closure (S1), as well as aortic and pulmonary valve Pulmonary valve A valve situated at the entrance to the pulmonary trunk from the right ventricle. Heart: Anatomy closure (S2). The third heart sound (S3) may be physiologic (e.g., athletes) or pathologic (e.g., congestive heart failure Heart Failure A heterogeneous condition in which the heart is unable to pump out sufficient blood to meet the metabolic need of the body. Heart failure can be caused by structural defects, functional abnormalities (ventricular dysfunction), or a sudden overload beyond its capacity. Chronic heart failure is more common than acute heart failure which results from sudden insult to cardiac function, such as myocardial infarction. Total Anomalous Pulmonary Venous Return (TAPVR)), and is related to abnormally rapid deceleration Deceleration A decrease in the rate of speed. Blunt Chest Trauma of early diastolic left ventricular inflow. The fourth heart sound (S4) is associated with contraction of the atria into partially-filled and non-compliant (stiff) ventricles. S4 is a pathologic sign in the young, but may be found in older individuals due to an age-related decrease in ventricular compliance Compliance Distensibility measure of a chamber such as the lungs (lung compliance) or bladder. Compliance is expressed as a change in volume per unit change in pressure. Veins: Histology. Additional sounds include murmurs (physiologic and pathologic), clicks, and snaps. These sounds are heard in individuals with structural abnormalities of the heart such as septal defects, valvular stenosis Stenosis Hypoplastic Left Heart Syndrome (HLHS), and mitral regurgitation Regurgitation Gastroesophageal Reflux Disease (GERD).

Last updated: Jul 4, 2023

Editorial responsibility: Stanley Oiseth, Lindsay Jones, Evelin Maza

Overview

Heart sounds

  • Heart sounds are produced by:
    • Valve opening and closure
    • Movement of blood in the heart
  • The more turbulent the flow Flow Blood flows through the heart, arteries, capillaries, and veins in a closed, continuous circuit. Flow is the movement of volume per unit of time. Flow is affected by the pressure gradient and the resistance fluid encounters between 2 points. Vascular resistance is the opposition to flow, which is caused primarily by blood friction against vessel walls. Vascular Resistance, Flow, and Mean Arterial Pressure, the more audible the created vibrations.
  • On auscultation, 2 heart sounds heard from a normal heart are reflective of the cardiac cycle Cardiac cycle The cardiac cycle describes a complete contraction and relaxation of all 4 chambers of the heart during a standard heartbeat. The cardiac cycle includes 7 phases, which together describe the cycle of ventricular filling, isovolumetric contraction, ventricular ejection, and isovolumetric relaxation. Cardiac Cycle.
    • The cardiac cycle Cardiac cycle The cardiac cycle describes a complete contraction and relaxation of all 4 chambers of the heart during a standard heartbeat. The cardiac cycle includes 7 phases, which together describe the cycle of ventricular filling, isovolumetric contraction, ventricular ejection, and isovolumetric relaxation. Cardiac Cycle is a sequence of pressure changes in the heart, resulting in:
      • Systole Systole Period of contraction of the heart, especially of the heart ventricles. Cardiac Cycle (ventricular contraction and ejection of blood) and
      • Diastole Diastole Post-systolic relaxation of the heart, especially the heart ventricles. Cardiac Cycle (ventricular relaxation and filling)
    • S1 and S2 mark the beginning and end, respectively, of the cardiac cycle Cardiac cycle The cardiac cycle describes a complete contraction and relaxation of all 4 chambers of the heart during a standard heartbeat. The cardiac cycle includes 7 phases, which together describe the cycle of ventricular filling, isovolumetric contraction, ventricular ejection, and isovolumetric relaxation. Cardiac Cycle phases: systole Systole Period of contraction of the heart, especially of the heart ventricles. Cardiac Cycle and diastole Diastole Post-systolic relaxation of the heart, especially the heart ventricles. Cardiac Cycle; they are high-frequency sounds.
    • Colloquially referred to as the “lub-dub” sound of the heart
  • S3 and S4 are low-frequency sounds which may be heard in various conditions.
Table: Heart sounds
Sound Timing Association
S1 Isovolumetric contraction Isovolumetric contraction Cardiac Cycle (beginning of systole Systole Period of contraction of the heart, especially of the heart ventricles. Cardiac Cycle) Closure of atrioventricular valves
S2 Isovolumetric relaxation Isovolumetric relaxation Cardiac Cycle (beginning of diastole Diastole Post-systolic relaxation of the heart, especially the heart ventricles. Cardiac Cycle) Closure of semilunar valves
S3 Rapid filling of ventricles (early diastole Diastole Post-systolic relaxation of the heart, especially the heart ventricles. Cardiac Cycle)
  • Normal in pregnant women, children, athletes
  • Ventricular dilation (e.g., congestive heart failure Heart Failure A heterogeneous condition in which the heart is unable to pump out sufficient blood to meet the metabolic need of the body. Heart failure can be caused by structural defects, functional abnormalities (ventricular dysfunction), or a sudden overload beyond its capacity. Chronic heart failure is more common than acute heart failure which results from sudden insult to cardiac function, such as myocardial infarction. Total Anomalous Pulmonary Venous Return (TAPVR))
S4 Late filling of ventricles by atrial contraction (late diastole Diastole Post-systolic relaxation of the heart, especially the heart ventricles. Cardiac Cycle)
  • Noncompliant or stiff ventricles
  • Pathologic in children and young people
  • May be seen in older people with age-related stiff ventricles

S1 and S2

S1

S1

S1:
Closure of the atrioventricular valves (tricuspid and mitral) at the beginning of systole. In the systole phase of the cardiac cycle, the right and left ventricles develop pressure, leading to ventricular contraction and ejection of blood into the pulmonary artery and aorta, respectively. Thus, the pulmonary and aortic valves are open. The closed atrioventricular valves prevent the backflow of blood into the atria during ventricular contraction.

Image: “2013 Blood Flow Contracted Ventricles” by OpenStax College. License: CC BY 3.0

S2

  • Closure of the semilunar valves (pulmonary and aortic)
  • Indicates the start of diastole Diastole Post-systolic relaxation of the heart, especially the heart ventricles. Cardiac Cycle
  • Occurs just after the T-wave and coincides with isovolumetric relaxation Isovolumetric relaxation Cardiac Cycle (beginning of diastole Diastole Post-systolic relaxation of the heart, especially the heart ventricles. Cardiac Cycle)
  • The aortic valve Aortic valve The valve between the left ventricle and the ascending aorta which prevents backflow into the left ventricle. Heart: Anatomy (A2 component of S2) closes before the pulmonic valve (P2 component of S2).
  • Loudest at left upper sternal border

Audio:

Normal S1 and S2: In this audio clip, normal S1 and S2 heart sounds can be heard. S1 corresponds to the closure of the AV valves, marking the beginning of systole Systole Period of contraction of the heart, especially of the heart ventricles. Cardiac Cycle. S2 corresponds to the closure of the semilunar valves, marking the beginning of diastole Diastole Post-systolic relaxation of the heart, especially the heart ventricles. Cardiac Cycle.

Heart sound by The Regents of the University of Michigan. License: CC BY-SA 3.0

S3 and S4

S3 and S4 sounds are heard in certain clinical situations and are produced by turbulent blood entering the ventricle at different points during diastole. S3 and S4 are the so-called “extra heart sounds.” They are low-frequency sounds.

S3

  • Rapid filling phase of ventricular diastole Ventricular diastole Cardiac Cycle
  • ↑ Left ventricular filling Ventricular filling Cardiac Cycle pressure → ↑ cardiac output Cardiac output The volume of blood passing through the heart per unit of time. It is usually expressed as liters (volume) per minute so as not to be confused with stroke volume (volume per beat). Cardiac Mechanics
  • Best heard at the apex (left lateral decubitus position)
  • Can be normal in children, pregnant women, and athletes
  • Associated pathologic conditions:
    • Dilated cardiomyopathy Dilated Cardiomyopathy Dilated cardiomyopathy (DCM) is the most common type of non-ischemic cardiomyopathy and a common cause of heart failure (HF). The cause may be idiopathic, familial, or secondary to a variety of underlying conditions. The disease is characterized by the enlargement of 1 or both ventricles and reduced systolic function. Dilated Cardiomyopathy
    • Congestive heart failure Heart Failure A heterogeneous condition in which the heart is unable to pump out sufficient blood to meet the metabolic need of the body. Heart failure can be caused by structural defects, functional abnormalities (ventricular dysfunction), or a sudden overload beyond its capacity. Chronic heart failure is more common than acute heart failure which results from sudden insult to cardiac function, such as myocardial infarction. Total Anomalous Pulmonary Venous Return (TAPVR)
    • Chronic mitral regurgitation Regurgitation Gastroesophageal Reflux Disease (GERD) ( MR MR Calculated as the ratio of the total number of people who die due to all causes over a specific time period to the total number of people in the selected population. Measures of Health Status)
    • Chronic aortic regurgitation Regurgitation Gastroesophageal Reflux Disease (GERD) ( AR AR Aortic regurgitation (AR) is a cardiac condition characterized by the backflow of blood from the aorta to the left ventricle during diastole. Aortic regurgitation is associated with an abnormal aortic valve and/or aortic root stemming from multiple causes, commonly rheumatic heart disease as well as congenital and degenerative valvular disorders. Aortic Regurgitation)
    • Thyrotoxicosis Thyrotoxicosis A hypermetabolic syndrome caused by excess thyroid hormones which may come from endogenous or exogenous sources. The endogenous source of hormone may be thyroid hyperplasia; thyroid neoplasms; or hormone-producing extrathyroidal tissue. Thyrotoxicosis is characterized by nervousness; tachycardia; fatigue; weight loss; heat intolerance; and excessive sweating. Thyrotoxicosis and Hyperthyroidism
Timing and amplitude of s3

Timing and amplitude of S3 when inaudible and audible

Image by Lecturio.

Audio:

S3: In this audio clip, the S3 gallop S3 gallop Heart Failure can be heard (left decubitus, heard with the bell of the stethoscope). S3 occurs after S2 during the rapid filling phase of ventricular diastole Ventricular diastole Cardiac Cycle.

Heart sound by The Regents of the University of Michigan. License: CC BY-SA 3.0

S4

  • Atrial contraction or “kick” during ventricular diastole Ventricular diastole Cardiac Cycle
  • Due to ventricular noncompliance Noncompliance Clinician–Patient Relationship or stiffness
  • May be auscultated in older adults due to loss of ventricular compliance Compliance Distensibility measure of a chamber such as the lungs (lung compliance) or bladder. Compliance is expressed as a change in volume per unit change in pressure. Veins: Histology with age
  • Best heard at the apex (left lateral decubitus position)
  • Associated conditions:
    • Hypertrophic cardiomyopathy Hypertrophic Cardiomyopathy Hypertrophic cardiomyopathy (HCM) is the most commonly inherited cardiomyopathy, which is characterized by an asymmetric increase in thickness (hypertrophy) of the left ventricular wall, diastolic dysfunction, and often left ventricular outflow tract obstruction. Hypertrophic Cardiomyopathy
    • AS
Timing and amplitude of s4

Timing and amplitude of S4 when inaudible and audible

Image by Lecturio.

Audio:

S4 gallop: In this audio clip, the S4 gallop can be heard (left decubitus, heard with the bell of the stethoscope). S4 occurs before S1 during the atrial filling phase. S4 is heard in conditions where there is stiffness or low compliance Compliance Distensibility measure of a chamber such as the lungs (lung compliance) or bladder. Compliance is expressed as a change in volume per unit change in pressure. Veins: Histology in the ventricle.

Heart sound by The Regents of the University of Michigan. License: CC BY-SA 3.0

Respiratory Variation

An increase in right ventricular (RV) volume (occurring with inspiration Inspiration Ventilation: Mechanics of Breathing) affects the right side of the heart and is heard as splitting Splitting Defense Mechanisms of S2 (A2 and P2).

Physiologic splitting Splitting Defense Mechanisms

Widening of the components of s2

Diagram showing widening of the S2 components (A2 and P2) during increased preload conditions such as inspiration, which produces the physiologic splitting of S2

Image by Lecturio.

Widened or persistent splitting Splitting Defense Mechanisms

Persistent splitting of s2

Diagram showing persistent S2 splitting in which closure of the pulmonic valve is further delayed by inspiration (right). This splitting can occur in a right bundle branch block.

Image by Lecturio.

Audio:

Persistent S2 splitting Splitting Defense Mechanisms: heard in right bundle branch block Right bundle branch block Bundle Branch and Fascicular Blocks (listening with the diaphragm Diaphragm The diaphragm is a large, dome-shaped muscle that separates the thoracic cavity from the abdominal cavity. The diaphragm consists of muscle fibers and a large central tendon, which is divided into right and left parts. As the primary muscle of inspiration, the diaphragm contributes 75% of the total inspiratory muscle force. Diaphragm: Anatomy of the stethoscope)

Heart sound by The Regents of the University of Michigan. License: CC BY-SA 3.0

Fixed splitting Splitting Defense Mechanisms

  • Description:
    • ↑ Right atrial (RA) and RV volume (due to left-to-right shunt)
    • Blood flow Blood flow Blood flow refers to the movement of a certain volume of blood through the vasculature over a given unit of time (e.g., mL per minute). Vascular Resistance, Flow, and Mean Arterial Pressure through the pulmonic valve
    • Delays closure of the pulmonic valve
  • Associated condition: atrial septal defect Atrial Septal Defect Atrial septal defects (ASDs) are benign acyanotic congenital heart defects characterized by an opening in the interatrial septum that causes blood to flow from the left atrium (LA) to the right atrium (RA) (left-to-right shunt). Atrial Septal Defect (ASD) ( ASD ASD Autism spectrum disorder (ASD) is a neurodevelopmental disorder marked by poor social skills, restricted interests/social interactions, and repetitive/stereotyped behaviors. The condition is termed a “spectrum” because of the wide variability in the severity of symptoms exhibited. Autism Spectrum Disorder)
Fixed splitting

Diagram showing fixed splitting, in which closure of P2 is NOT delayed by inspiration (right)

Image by Lecturio.

Paradoxical splitting Splitting Defense Mechanisms

  • Description:
    • Delayed aortic valve Aortic valve The valve between the left ventricle and the ascending aorta which prevents backflow into the left ventricle. Heart: Anatomy closure
    • Pulmonic valve closure (P2) occurs before delayed aortic valve Aortic valve The valve between the left ventricle and the ascending aorta which prevents backflow into the left ventricle. Heart: Anatomy closure (A2).
  • Associated conditions:
Paradoxical splitting of s2

Diagram showing paradoxical splitting in which closure of the aortic valve is delayed: The name “paradoxical” is because the split narrows the inspiration (right). The split can be heard in some individuals with a left bundle branch block.

Image by Lecturio.

Clicks and Snaps

Clicks

  • A high-pitched sound occurring at the point of maximal opening of the valves
  • Occurs after S1 (systolic)
  • Can be ejection or nonejection clicks:
Diagram depicting the the mid-systolic click

Schematic diagram depicting the mid-systolic click (MSC): MSC occurs after S1.

Image by Lecturio.

Audio:

Mid-systolic click (MSC): This audio clip is an example of an MSC heard in mitral valve Mitral valve The valve between the left atrium and left ventricle of the heart. Heart: Anatomy prolapse. An MSC is a crisp sound occurring between S1 and S2 (no murmur follows).

Heart sound by The Regents of the University of Michigan. License: CC BY-SA 3.0

Snap

  • A high-frequency diastolic sound made by the opening of a stenotic mitral valve Mitral valve The valve between the left atrium and left ventricle of the heart. Heart: Anatomy (most common)
  • Leaflets swell out into the ventricle and suddenly stop, producing a mid-to-high–frequency sound.
Diastolic filling and rumbling murmur of mild and severe mitral stenosis

Diastolic filling and rumbling murmur in mild and severe mitral stenosis:
The mid-diastolic murmur starts after the opening snap (O.S.). The presystolic murmur is due to atrial contraction (absent in atrial fibrillation) and is best heard over the apex with the bell of a stethoscope.

Image by Lecturio.

Audio:

Opening snap Opening snap Mitral Stenosis: A mitral stenosis Stenosis Hypoplastic Left Heart Syndrome (HLHS) murmur can be heard in this audio clip. The low-pitched, rumbling murmur starts after the opening snap Opening snap Mitral Stenosis of the mitral valve Mitral valve The valve between the left atrium and left ventricle of the heart. Heart: Anatomy (after S2) and finishes with a short crescendo up to S1.

Heart sound by The Regents of the University of Michigan. License: CC BY-SA 3.0

Murmurs

Heart murmurs

  • Murmurs are audible vibrations that can be produced by the following:
  • Not all murmurs indicate structural heart disease.
  • Determine characteristics by:
    • Timing ( cardiac cycle Cardiac cycle The cardiac cycle describes a complete contraction and relaxation of all 4 chambers of the heart during a standard heartbeat. The cardiac cycle includes 7 phases, which together describe the cycle of ventricular filling, isovolumetric contraction, ventricular ejection, and isovolumetric relaxation. Cardiac Cycle)
    • Intensity
    • Pattern or configuration
    • Pitch and quality Quality Activities and programs intended to assure or improve the quality of care in either a defined medical setting or a program. The concept includes the assessment or evaluation of the quality of care; identification of problems or shortcomings in the delivery of care; designing activities to overcome these deficiencies; and follow-up monitoring to ensure effectiveness of corrective steps. Quality Measurement and Improvement
    • Location or auscultation area
    • Maneuvers, position, and exercise

Classification according to cardiac cycle Cardiac cycle The cardiac cycle describes a complete contraction and relaxation of all 4 chambers of the heart during a standard heartbeat. The cardiac cycle includes 7 phases, which together describe the cycle of ventricular filling, isovolumetric contraction, ventricular ejection, and isovolumetric relaxation. Cardiac Cycle

Patterns of heart murmurs

Patterns of heart murmurs (with examples):
A: presystolic or late diastolic, crescendo murmur (tricuspid stenosis)
B: holosystolic murmur (mitral regurgitation)
C: midsystolic, crescendo-decrescendo murmur (aortic stenosis)
D: long systolic, crescendo-decrescendo murmur (pulmonic stenosis)
E: early diastolic, decrescendo murmur (aortic regurgitation)
F: mid-diastolic murmur (mitral stenosis)
G: short mid-diastolic murmur
H: continuous murmur (patent ductus arteriosus)

Image by Lecturio.
Ar murmur simplification

Diastolic murmur: Chronic aortic regurgitation (AR) results in an early diastolic murmur (high pitched). The murmur becomes holodiastolic in severe AR.

Image by Lecturio.

Audio:

Early diastolic murmur: Aortic regurgitation Regurgitation Gastroesophageal Reflux Disease (GERD), a high-pitched decrescendo murmur, can be heard in this audio clip.

Heart sound by The Regents of the University of Michigan. License: CC BY-SA 3.0
Holosystolic murmur

Holosystolic murmur: Chronic mitral regurgitation can be heard as a holosystolic murmur at the apex, radiating to the axilla.

Image by Lecturio.

Audio:

Holosystolic murmur Holosystolic Murmur Tricuspid Valve Atresia (TVA): This audio clip presents an example of a holosystolic murmur Holosystolic Murmur Tricuspid Valve Atresia (TVA) from MR MR Calculated as the ratio of the total number of people who die due to all causes over a specific time period to the total number of people in the selected population. Measures of Health Status. The murmur results in a high-pitched “blowing” sound through the entirety of the systole Systole Period of contraction of the heart, especially of the heart ventricles. Cardiac Cycle.

Heart sound by The Regents of the University of Michigan. License: CC BY-SA 3.0

Classification according to intensity

Using the Levine system, murmurs can be graded on a scale Scale Dermatologic Examination from I to VI, which reflects the intensity of the murmur. 

  • I: very soft, may only be heard by experienced cardiologists
  • II: faint but readily audible
  • III: readily audible, louder than grade 2, no thrill
  • IV: loud and accompanied by a palpable thrill
  • V: loud enough to be heard with a stethoscope lightly touching the chest
  • VI: loud enough to be heard with a stethoscope off the chest

Classification according to pattern

  • Crescendo-decrescendo murmur:
    • Ascending then descending systolic ejection murmur
    • Diamond shaped
    • Example: AS
  • Crescendo:
    • Ascending intensity from faint to loud
    • Example: can be heard in mitral valve Mitral valve The valve between the left atrium and left ventricle of the heart. Heart: Anatomy prolapse
  • Decrescendo:
    • Descending intensity from loud to faint
    • Example: AR AR Aortic regurgitation (AR) is a cardiac condition characterized by the backflow of blood from the aorta to the left ventricle during diastole. Aortic regurgitation is associated with an abnormal aortic valve and/or aortic root stemming from multiple causes, commonly rheumatic heart disease as well as congenital and degenerative valvular disorders. Aortic Regurgitation
  • Uniform/ plateau Plateau Cardiac Physiology: mitral/TR murmur
Crescendo-decrescendo murmurs

Crescendo-decrescendo murmurs: ascending then descending systolic murmur (diamond shaped) heard in aortic stenosis

Image by Lecturio.

Audio:

Crescendo-decrescendo murmur: In this audio clip, the sound of severe AS, a harsh, crescendo-decrescendo murmur occurring between S1 and S2, can be heard. The S2 heart sound is inaudible due to the severity of AS.

Heart sound by The Regents of the University of Michigan. License: CC BY-SA 3.0

Classification according to pitch and quality Quality Activities and programs intended to assure or improve the quality of care in either a defined medical setting or a program. The concept includes the assessment or evaluation of the quality of care; identification of problems or shortcomings in the delivery of care; designing activities to overcome these deficiencies; and follow-up monitoring to ensure effectiveness of corrective steps. Quality Measurement and Improvement

  • Pitch:
    • Frequency of the murmur
    • High pitch:
      • TR
      • MR MR Calculated as the ratio of the total number of people who die due to all causes over a specific time period to the total number of people in the selected population. Measures of Health Status
      • AR AR Aortic regurgitation (AR) is a cardiac condition characterized by the backflow of blood from the aorta to the left ventricle during diastole. Aortic regurgitation is associated with an abnormal aortic valve and/or aortic root stemming from multiple causes, commonly rheumatic heart disease as well as congenital and degenerative valvular disorders. Aortic Regurgitation
    • Low pitch: mitral stenosis Stenosis Hypoplastic Left Heart Syndrome (HLHS)
  • Quality Quality Activities and programs intended to assure or improve the quality of care in either a defined medical setting or a program. The concept includes the assessment or evaluation of the quality of care; identification of problems or shortcomings in the delivery of care; designing activities to overcome these deficiencies; and follow-up monitoring to ensure effectiveness of corrective steps. Quality Measurement and Improvement: can be blowing, harsh, rumbling, scratchy, vibratory, squeaky, or musical

Auscultation areas

The 5 areas of auscultation can be recalled using the mnemonic, “All People Enjoy Time Magazine.”

  1. Aortic area: right 2nd intercostal space adjacent to the sternum Sternum A long, narrow, and flat bone commonly known as breastbone occurring in the midsection of the anterior thoracic segment or chest region, which stabilizes the rib cage and serves as the point of origin for several muscles that move the arms, head, and neck. Chest Wall: Anatomy
    • AS
    • Aortic valve Aortic valve The valve between the left ventricle and the ascending aorta which prevents backflow into the left ventricle. Heart: Anatomy sclerosis Sclerosis A pathological process consisting of hardening or fibrosis of an anatomical structure, often a vessel or a nerve. Wilms Tumor
    • Systolic flow Flow Blood flows through the heart, arteries, capillaries, and veins in a closed, continuous circuit. Flow is the movement of volume per unit of time. Flow is affected by the pressure gradient and the resistance fluid encounters between 2 points. Vascular resistance is the opposition to flow, which is caused primarily by blood friction against vessel walls. Vascular Resistance, Flow, and Mean Arterial Pressure murmurs
  2. Pulmonic area: left 2nd intercostal space adjacent to the sternum Sternum A long, narrow, and flat bone commonly known as breastbone occurring in the midsection of the anterior thoracic segment or chest region, which stabilizes the rib cage and serves as the point of origin for several muscles that move the arms, head, and neck. Chest Wall: Anatomy
    • PS PS Invasive Mechanical Ventilation
    • Systolic flow Flow Blood flows through the heart, arteries, capillaries, and veins in a closed, continuous circuit. Flow is the movement of volume per unit of time. Flow is affected by the pressure gradient and the resistance fluid encounters between 2 points. Vascular resistance is the opposition to flow, which is caused primarily by blood friction against vessel walls. Vascular Resistance, Flow, and Mean Arterial Pressure murmurs
  3. E rb RB Chlamydia’s (auscultation) point (left sternal border): left 3rd intercostal space
    • Systolic murmurs: HOCM
    • Diastolic murmurs:
      • AR AR Aortic regurgitation (AR) is a cardiac condition characterized by the backflow of blood from the aorta to the left ventricle during diastole. Aortic regurgitation is associated with an abnormal aortic valve and/or aortic root stemming from multiple causes, commonly rheumatic heart disease as well as congenital and degenerative valvular disorders. Aortic Regurgitation
      • Pulmonic regurgitation Regurgitation Gastroesophageal Reflux Disease (GERD) (PR)
  4. Tricuspid area: left 4th–5th intercostal space adjacent to the sternum Sternum A long, narrow, and flat bone commonly known as breastbone occurring in the midsection of the anterior thoracic segment or chest region, which stabilizes the rib cage and serves as the point of origin for several muscles that move the arms, head, and neck. Chest Wall: Anatomy
    • Systolic murmurs:
      • TR
      • VSD
    • Diastolic murmurs:
      • TS
      • ASD ASD Autism spectrum disorder (ASD) is a neurodevelopmental disorder marked by poor social skills, restricted interests/social interactions, and repetitive/stereotyped behaviors. The condition is termed a “spectrum” because of the wide variability in the severity of symptoms exhibited. Autism Spectrum Disorder
  5. Mitral area (apex): left 4th intercostal space, midclavicular line
    • Systolic murmurs:
      • MR MR Calculated as the ratio of the total number of people who die due to all causes over a specific time period to the total number of people in the selected population. Measures of Health Status (holosystolic)
      • Mitral valve Mitral valve The valve between the left atrium and left ventricle of the heart. Heart: Anatomy prolapse
    • Diastolic murmurs: mitral stenosis Stenosis Hypoplastic Left Heart Syndrome (HLHS) ( MS MS Multiple sclerosis (MS) is a chronic inflammatory autoimmune disease that leads to demyelination of the nerves in the CNS. Young women are more predominantly affected by this most common demyelinating condition. Multiple Sclerosis)
Auscultation areas

Auscultation areas and associated murmurs that are heard: aortic, pulmonic, Erb’s point, tricuspid, and mitral areas (APETM)
TR: tricuspid regurgitation
VSD: ventricular septal defect
TS: tricuspid stenosis
ASD: atrial septal defect
MR: mitral regurgitation
MS: mitral stenosis

Image by Lecturio.

Dynamic Auscultation

Cardiac physiology Cardiac Physiology A complex system of coordinated electrical circuitry within the heart governs cardiac muscle activity. The heart generates its own electrical impulses within its pacemaker cells. The signal then travels through specialized myocytes, which act as electrical wiring, distributing the signal throughout the heart. Cardiac Physiology and maneuvers

  • Preload Preload Cardiac Mechanics:
    • Stretching of cardiac muscles prior to contraction ( ventricular filling Ventricular filling Cardiac Cycle)
    • Preload Preload Cardiac Mechanics: increase in venous return into the right ventricle and decrease in venous return to the left ventricle:
      • Deep inspiration Inspiration Ventilation: Mechanics of Breathing
      • Supine position
      • Squatting (seen in tetralogy of Fallot Tetralogy of Fallot Tetralogy of Fallot is the most common cyanotic congenital heart disease. The disease is the confluence of 4 pathologic cardiac features: overriding aorta, ventricular septal defect, right ventricular outflow obstruction, and right ventricular hypertrophy. Tetralogy of Fallot)
      • Passive leg Leg The lower leg, or just “leg” in anatomical terms, is the part of the lower limb between the knee and the ankle joint. The bony structure is composed of the tibia and fibula bones, and the muscles of the leg are grouped into the anterior, lateral, and posterior compartments by extensions of fascia. Leg: Anatomy raise (increased venous return due to gravity)
    • Preload Preload Cardiac Mechanics: decrease in venous return → ↓ LV volume
  • Afterload Afterload Afterload is the resistance in the aorta that prevents blood from leaving the heart. Afterload represents the pressure the LV needs to overcome to eject blood into the aorta. Cardiac Mechanics:
    • Effective pressure against which the heart ejects blood during ventricular contraction
    • Afterload Afterload Afterload is the resistance in the aorta that prevents blood from leaving the heart. Afterload represents the pressure the LV needs to overcome to eject blood into the aorta. Cardiac Mechanics: handgrip

Effects on the intensity of heart murmurs

  • Respiration Respiration The act of breathing with the lungs, consisting of inhalation, or the taking into the lungs of the ambient air, and of exhalation, or the expelling of the modified air which contains more carbon dioxide than the air taken in. Nose Anatomy (External & Internal) ( preload Preload Cardiac Mechanics):
  • While standing and with the Valsalva maneuver Valsalva maneuver Forced expiratory effort against a closed glottis. Rectal Prolapse ( preload Preload Cardiac Mechanics), most murmurs decrease, EXCEPT the following:
    • HOCM (becomes louder)
    • Mitral valve Mitral valve The valve between the left atrium and left ventricle of the heart. Heart: Anatomy prolapse (becomes longer and louder)
  • While squatting and with passive leg Leg The lower leg, or just “leg” in anatomical terms, is the part of the lower limb between the knee and the ankle joint. The bony structure is composed of the tibia and fibula bones, and the muscles of the leg are grouped into the anterior, lateral, and posterior compartments by extensions of fascia. Leg: Anatomy raise (↑ preload Preload Cardiac Mechanics), most murmurs become louder, EXCEPT:
    • HOCM (becomes softer)
    • Mitral valve Mitral valve The valve between the left atrium and left ventricle of the heart. Heart: Anatomy prolapse (becomes shorter, except in severe MR MR Calculated as the ratio of the total number of people who die due to all causes over a specific time period to the total number of people in the selected population. Measures of Health Status)
  • With isotonic Isotonic Solutions having the same osmotic pressure as blood serum, or another solution with which they are compared. Renal Sodium and Water Regulation and isometric (sustained handgrip) exercise ( afterload Afterload Afterload is the resistance in the aorta that prevents blood from leaving the heart. Afterload represents the pressure the LV needs to overcome to eject blood into the aorta. Cardiac Mechanics), most murmurs increase, EXCEPT:
    • HOCM (decreases in intensity)
    • AS (decreases in intensity, helping to differentiate AS from MR MR Calculated as the ratio of the total number of people who die due to all causes over a specific time period to the total number of people in the selected population. Measures of Health Status)
Table: Maneuvers that change the intensity of murmurs
Physiologic changes Maneuver Murmurs that increase with maneuver Murmurs that decrease with maneuver
Increased preload Preload Cardiac Mechanics (on the right) Inspiration Inspiration Ventilation: Mechanics of Breathing Most right-sided murmurs Most left-sided murmurs
Increased preload Preload Cardiac Mechanics
  • Lying supine
  • Passive leg Leg The lower leg, or just “leg” in anatomical terms, is the part of the lower limb between the knee and the ankle joint. The bony structure is composed of the tibia and fibula bones, and the muscles of the leg are grouped into the anterior, lateral, and posterior compartments by extensions of fascia. Leg: Anatomy raise
  • Squatting
Most murmurs
Decreased preload Preload Cardiac Mechanics
  • Valsalva (straining)
  • Abrupt standing
Most murmurs
Increased afterload Afterload Afterload is the resistance in the aorta that prevents blood from leaving the heart. Afterload represents the pressure the LV needs to overcome to eject blood into the aorta. Cardiac Mechanics Handgrip Most murmurs, especially AR AR Aortic regurgitation (AR) is a cardiac condition characterized by the backflow of blood from the aorta to the left ventricle during diastole. Aortic regurgitation is associated with an abnormal aortic valve and/or aortic root stemming from multiple causes, commonly rheumatic heart disease as well as congenital and degenerative valvular disorders. Aortic Regurgitation, MR MR Calculated as the ratio of the total number of people who die due to all causes over a specific time period to the total number of people in the selected population. Measures of Health Status, VSD
  • AS
  • HOCM
HOCM: hypertrophic obstructive cardiomyopathy
AS: aortic stenosis
AR: aortic regurgitation
MR: mitral regurgitation
VSD: ventricular septal defect

Mnemonics

  • rIght-sided murmurs: increase with Inspiration
  • lEft-sided murmurs: increase with Expiration

Specific Murmurs

The table below lists cardiac abnormalities with their corresponding murmurs.

Table: Systolic murmurs
Type Cardiac cycle Cardiac cycle The cardiac cycle describes a complete contraction and relaxation of all 4 chambers of the heart during a standard heartbeat. The cardiac cycle includes 7 phases, which together describe the cycle of ventricular filling, isovolumetric contraction, ventricular ejection, and isovolumetric relaxation. Cardiac Cycle Pattern Location Additional description
Aortic stenosis Stenosis Hypoplastic Left Heart Syndrome (HLHS) Systolic Crescendo-decrescendo murmur Right 2nd ICS (aortic)
Pulmonic stenosis Stenosis Hypoplastic Left Heart Syndrome (HLHS) Systolic Crescendo-decrescendo murmur Left 2nd ICS (pulmonic)
Mitral valve Mitral valve The valve between the left atrium and left ventricle of the heart. Heart: Anatomy prolapse Systolic Click, crescendo into S2 (can vary with severity) Left 4th ICS (mitral) Mid-to-late systolic click
Mitral regurgitation Regurgitation Gastroesophageal Reflux Disease (GERD) Systolic Uniform (holosystolic) Left 4th ICS (mitral)
  • Holosystolic,
high pitched
  • Radiates to axilla Axilla The axilla is a pyramid-shaped space located between the upper thorax and the arm. The axilla has a base, an apex, and 4 walls (anterior, medial, lateral, posterior). The base of the pyramid is made up of the axillary skin. The apex is the axillary inlet, located between the 1st rib, superior border of the scapula, and clavicle. Axilla and Brachial Plexus: Anatomy
Tricuspid regurgitation Regurgitation Gastroesophageal Reflux Disease (GERD) Systolic Uniform (holosystolic) LLSB (tricuspid)
VSD Systolic Uniform (holosystolic) LLSB (tricuspid)
Harsh, loud murmur
ICS: intercostal
LLSB: left lower sternal border
VSD: ventricular septal defect
Table: Diastolic murmurs
Type Cardiac cycle Cardiac cycle The cardiac cycle describes a complete contraction and relaxation of all 4 chambers of the heart during a standard heartbeat. The cardiac cycle includes 7 phases, which together describe the cycle of ventricular filling, isovolumetric contraction, ventricular ejection, and isovolumetric relaxation. Cardiac Cycle Pattern Location Additional description
AR AR Aortic regurgitation (AR) is a cardiac condition characterized by the backflow of blood from the aorta to the left ventricle during diastole. Aortic regurgitation is associated with an abnormal aortic valve and/or aortic root stemming from multiple causes, commonly rheumatic heart disease as well as congenital and degenerative valvular disorders. Aortic Regurgitation Diastolic Decrescendo Erb’s point
  • S3 in acute AR AR Aortic regurgitation (AR) is a cardiac condition characterized by the backflow of blood from the aorta to the left ventricle during diastole. Aortic regurgitation is associated with an abnormal aortic valve and/or aortic root stemming from multiple causes, commonly rheumatic heart disease as well as congenital and degenerative valvular disorders. Aortic Regurgitation
  • High pitched
Pulmonary regurgitation Regurgitation Gastroesophageal Reflux Disease (GERD) Diastolic Decrescendo Erb’s point ↑ With inspiration Inspiration Ventilation: Mechanics of Breathing
Mitral stenosis Stenosis Hypoplastic Left Heart Syndrome (HLHS) Diastolic Opening snap Opening snap Mitral Stenosis followed by decrescendo-crescendo murmur Left 4th ICS (mitral)
Tricuspid stenosis Stenosis Hypoplastic Left Heart Syndrome (HLHS) Diastolic Frequently with MS MS Multiple sclerosis (MS) is a chronic inflammatory autoimmune disease that leads to demyelination of the nerves in the CNS. Young women are more predominantly affected by this most common demyelinating condition. Multiple Sclerosis (but softer and shorter than MS MS Multiple sclerosis (MS) is a chronic inflammatory autoimmune disease that leads to demyelination of the nerves in the CNS. Young women are more predominantly affected by this most common demyelinating condition. Multiple Sclerosis) LLSB (tricuspid)
Patent ductus arteriosus Ductus arteriosus A fetal blood vessel connecting the pulmonary artery with the descending aorta. Patent Ductus Arteriosus (PDA) Continuous Crescendo-decrescendo murmur Left 1st and 2nd ICS Continuous machinery-like murmur
AR: aortic regurgitation
ICS: intercostal
LLSB: left lower sternal border
MS: mitral stenosis

Mnemonics for valvular murmurs

  • Systolic murmurs: MR. PV TR-APS
  • Diastolic murmurs: MS. PAR-TS
    • MS MS Multiple sclerosis (MS) is a chronic inflammatory autoimmune disease that leads to demyelination of the nerves in the CNS. Young women are more predominantly affected by this most common demyelinating condition. Multiple Sclerosis (Mitral Stenosis)
    • P (Pulmonary regurgitation Regurgitation Gastroesophageal Reflux Disease (GERD))
    • AR AR Aortic regurgitation (AR) is a cardiac condition characterized by the backflow of blood from the aorta to the left ventricle during diastole. Aortic regurgitation is associated with an abnormal aortic valve and/or aortic root stemming from multiple causes, commonly rheumatic heart disease as well as congenital and degenerative valvular disorders. Aortic Regurgitation (Aortic Regurgitation)
    • TS (Tricuspid Stenosis)

References

  1. Alpert, M.A. (1990). Systolic Murmurs. In Walker, H.K., et al. (Ed). Clinical Methods: The History, Physical, and Laboratory Examinations. (3rd ed.) https://www.ncbi.nlm.nih.gov/books/NBK345/
  2. Gersh, B. (2021). Physiologic and pharmacologic maneuvers in the differential diagnosis of heart murmurs and sounds. UpToDate. Retrieved Sept 4, 2021, from https://www.uptodate.com/contents/physiologic-and-pharmacologic-maneuvers-in-the-differential-diagnosis-of-heart-murmurs-and-sounds
  3. Gomella, L.G., Haist, S.A. (2007). History and physical examination. In Gomella, L.G., Haist, S.A. (Eds.), Clinician’s Pocket Reference: The Scut Monkey (11th ed.) https://accessmedicine.mhmedical.com/content.aspx?bookid=365&sectionid=43074910
  4. Jacobs, W.R. (1990). Ejection Clicks. In Walker, H.K., et al. (Ed.), Clinical Methods: The History, Physical, and Laboratory Examinations. (3rd ed.) https://www.ncbi.nlm.nih.gov/books/NBK347/
  5. McGee, S. (2018). Miscellaneous heart sounds. In S. McGee MD (Ed.), Evidence-based physical diagnosis (1st ed., pp. 355–360) http://dx.doi.org/10.1016/B978-0-323-39276-1.00042-1
  6. Meyer, T. (2021). Auscultation of cardiac murmurs. UpToDate. Retrieved Sept 5, 2021, from https://www.uptodate.com/contents/auscultation-of-cardiac-murmurs-in-adults#H2
  7. Mohrman, D.E., Heller, L.J. (2018). The heart pump. In Mohrman, D.E., Heller, L.J. (Eds.), Cardiovascular Physiology (9th ed.). accessmedicine.mhmedical.com/content.aspx?aid=1153946347
  8. O’Gara, P.T., Loscalzo, J. (2018). Approach to the patient with a heart murmur. In J.L. Jameson, et al. (Ed.), Harrison’s Principles of Internal Medicine (20th ed.). https://accessmedicine.mhmedical.com/content.aspx?bookid=2129&sectionid=192012631
  9. Williams, E.S. (1990). The Fourth Heart Sound. In Walker H.K., et al. (Ed.), Clinical Methods: The History, Physical, and Laboratory Examinations (3rd ed.) https://www.ncbi.nlm.nih.gov/books/NBK344/

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