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Heart murmurs are unique
heart sounds Heart sounds are the noises generated by the beating heart and the resultant flow of blood through it. Specifically, the sounds reflect the turbulence created when the heart valves snap shut. In cardiac auscultation, an examiner may use a steth ...
produced when
blood flow Hemodynamics or haemodynamics are the dynamics of blood flow. The circulatory system is controlled by homeostatic mechanisms of autoregulation, just as hydraulic circuits are controlled by control systems. The hemodynamic response continuously ...
s across a heart valve or blood vessel. This occurs when turbulent blood flow creates a sound loud enough to hear with a stethoscope. Turbulent blood flow is not smooth. The sound differs from normal heart sounds by their characteristics. For example, heart murmurs may have a distinct pitch, duration and timing. The major way health care providers examine the heart on physical exam is heart
auscultation Auscultation (based on the Latin verb ''auscultare'' "to listen") is listening to the internal sounds of the body, usually using a stethoscope. Auscultation is performed for the purposes of examining the circulatory and respiratory systems (hear ...
; another clinical technique is
palpation Palpation is the process of using one's hands to check the body, especially while perceiving/diagnosing a disease or illness. Usually performed by a health care practitioner, it is the process of feeling an object in or on the body to determine ...
, which can detect by touch when such turbulence causes the vibrations called cardiac thrill. A murmur is a sign found during the
cardiac exam In medicine, the cardiac examination, also precordial exam, is performed as part of a physical examination, or when a patient presents with chest pain suggestive of a cardiovascular pathology. It would typically be modified depending on the indi ...
. Murmurs are of various types and are important in the detection of cardiac and valvular pathologies (i.e. can be a sign of heart diseases or defects). There are two types of murmur. A
functional murmur A functional murmur (innocent murmur, physiologic murmur) is a heart murmur that is primarily due to physiologic conditions outside the heart, as opposed to structural defects in the heart itself. Serious conditions can arise even in the absence of ...
is a benign heart murmur that is primarily due to
physiologic Physiology (; ) is the scientific study of functions and mechanisms in a living system. As a sub-discipline of biology, physiology focuses on how organisms, organ systems, individual organs, cells, and biomolecules carry out the chemical a ...
conditions outside the heart. The other type of heart murmur is due to a structural defect in the heart itself. Defects may be due to narrowing of one or more valves (stenosis), backflow of blood, through a leaky valve, (regurgitation), or the presence of abnormal passages through which blood flows in or near the heart. Most murmurs are normal variants that can present at various ages which relate to changes of the body with age such as chest size, blood pressure, and pliability or rigidity of structures. Heart murmurs are frequently categorized by timing. These include
systolic heart murmur Systolic heart murmurs are heart murmurs heard during systole, i.e. they begin and end between S1 and S2. Many involve stenosis of the semilunar valves or regurgitation of the atrioventricular valves. Types * Mid-systolic ejection murmurs are ...
s,
diastolic heart murmur Diastolic heart murmurs are heart murmurs heard during diastole, i.e. they start at or after S2 and end before or at S1. Many involve stenosis of the atrioventricular valves or regurgitation of the semilunar valves. Types * Early diastolic mu ...
s, or continuous murmurs. These differ in the part of the heartbeat they make sound, during systole, or diastole. Yet, continuous murmurs create sound throughout both parts of the heartbeat. Continuous murmurs are not placed into the categories of diastolic or systolic murmurs.


Diagnostic approach and diagnosis


Classification

Murmurs have seven main characteristics. These include timing, shape, location, radiation, intensity, pitch and quality. * ''Timing'' refers to whether the murmur is a systolic,
diastolic Diastole ( ) is the relaxed phase of the cardiac cycle when the chambers of the heart are re-filling with blood. The contrasting phase is systole when the heart chambers are contracting. Atrial diastole is the relaxing of the atria, and ventricu ...
, or
continuous Continuity or continuous may refer to: Mathematics * Continuity (mathematics), the opposing concept to discreteness; common examples include ** Continuous probability distribution or random variable in probability and statistics ** Continuous g ...
murmur. * ''Shape'' refers to the intensity over time. Murmurs can be
crescendo In music, the dynamics of a piece is the variation in loudness between notes or phrases. Dynamics are indicated by specific musical notation, often in some detail. However, dynamics markings still require interpretation by the performer dependi ...
,
decrescendo In music, the dynamics of a piece is the variation in loudness between notes or phrases. Dynamics are indicated by specific musical notation, often in some detail. However, dynamics markings still require interpretation by the performer dependin ...
or crescendo-decrescendo. Crescendo murmurs increase in intensity over time. Decrescendo murmurs decrease in intensity over time. Crescendo-decrescendo murmurs have both shapes over time. These have progressive increase in intensity, peak, and progressive decrease in intensity. Crescendo–decrescendo murmurs resemble a diamond or kite shape. * ''Location'' refers to where the heart murmur is usually heard best. There are four places on the anterior chest wall to listen for heart murmurs. Each location roughly corresponds to a specific part of the heart. Health care providers listen to these areas with a stethoscope. * Position for
auscultation Auscultation (based on the Latin verb ''auscultare'' "to listen") is listening to the internal sounds of the body, usually using a stethoscope. Auscultation is performed for the purposes of examining the circulatory and respiratory systems (hear ...
: The patient is most often lying on their back (supine) with the head of bed at slight upward angle. The head of the bed is usually at a 30 degree upward angle. Usually the health care provider is standing to the right of the person they are examining. Below are positional changes that one may use: ** Left lateral decubitus (lying on the left side). This will decrease the distance from wall of the chest to the apex of the heart. This will help to examine the
point of maximal impulse Point or points may refer to: Places * Point, Lewis, a peninsula in the Outer Hebrides, Scotland * Point, Texas, a city in Rains County, Texas, United States * Point, the NE tip and a ferry terminal of Lismore, Inner Hebrides, Scotland * Point ...
. Also, this will help to hear extra heart sounds (S3 or S4). ** With the patient sitting upright. ** With the patient seated, leaning forward and holding breath after exhalation. This will decrease the distance of the chest wall to the left ventricular outflow tract. By doing so this will help find the presence of an aortic regurgitation murmur. * ''Radiation'' refers to where the sound of the murmur travels. The rule of thumb is that the sound radiates in the direction of the blood flow. * ''Intensity'' refers to the loudness of the murmur with grades according to the
Levine scale In cardiac physiology, the Levine grading scale is a numeric scoring system to characterize the intensity or the loudness of a heart murmur. The eponym is from researcher Samuel A. Levine who studied the significance of systolic heart murmurs. T ...
, from 1 to 6: * ''Pitch'' may be low, medium or high. This depends on whether auscultation is best with the bell or diaphragm of a stethoscope. * ''Quality'' refers to unusual characteristics of a murmur. For example, blowing, harsh, rumbling or musical.


Interventions that change murmur sounds

*
Inhalation Inhalation (or Inspiration) happens when air or other gases enter the lungs. Inhalation of air Inhalation of air, as part of the cycle of breathing, is a vital process for all human life. The process is autonomic (though there are exceptions ...
leads to an increase in intrathoracic negative pressure. This increases the capacity of
pulmonary circulation The pulmonary circulation is a division of the circulatory system in all vertebrates. The circuit begins with deoxygenated blood returned from the body to the right atrium of the heart where it is pumped out from the right ventricle to the lungs. ...
, thereby prolonging ejection time. This will affect the closure of the pulmonary valve. This finding is also called ''Carvallo's maneuver.'' This maneuver in studies had a sensitivity of 100% and a specificity of 80% to 88% in detecting murmurs originating in the right heart. Positive Carvallo's sign describes the increase in intensity of a tricuspid regurgitation murmur heard with inspiration. * Abrupt
standing Standing, also referred to as orthostasis, is a position in which the body is held in an ''erect'' ("orthostatic") position and supported only by the feet. Although seemingly static, the body rocks slightly back and forth from the ankle in the s ...
* Squatting, by increasing
afterload Afterload is the pressure that the heart must work against to eject blood during systole (ventricular contraction). Afterload is proportional to the average arterial pressure. As aortic and pulmonary pressures increase, the afterload increases on ...
and increasing preload. Squatting leads to an increase in
systemic vascular resistance Vascular resistance is the resistance that must be overcome to push blood through the circulatory system and create flow. The resistance offered by the systemic circulation is known as the systemic vascular resistance (SVR) or may sometimes be c ...
. An increase in systemic vascular resistance results in an increase in afterload. With HOCM, an increase in afterload will hold the obstruction in a more open configuration. This will decrease the loudness of the murmur with HOCM. * Handgrip maneuver, by increasing afterload. Like squatting, this will decrease the loudness of the HOCM murmur. *
Valsalva maneuver The Valsalva maneuver is performed by a forceful attempt of exhalation against a closed airway, usually done by closing one's mouth and pinching one's nose shut while expelling air out as if blowing up a balloon. Variations of the maneuver can ...
. Valsalva maneuver has utility in detecting hypertrophic obstructive cardiomyopathy (
HOCM Hypertrophic cardiomyopathy (HCM, or HOCM when obstructive) is a condition in which the heart becomes thickened without an obvious cause. The parts of the heart most commonly affected are the interventricular septum and the ventricles. This r ...
). According to one study, it has a sensitivity of 65% and specificity of 96% in
HOCM Hypertrophic cardiomyopathy (HCM, or HOCM when obstructive) is a condition in which the heart becomes thickened without an obvious cause. The parts of the heart most commonly affected are the interventricular septum and the ventricles. This r ...
. Valsalva maneuver, as well as standing, decrease venous return to the heart. As a result, this decreases left ventricular filling. With HOCM, the outflow obstruction increases with a decrease in preload. This will increase the loudness of the murmur with HOCM. * Post ectopic potentiation * Inhaled
amyl nitrite Amyl nitrite is a chemical compound with the formula C5H11ONO. A variety of isomers are known, but they all feature an amyl group attached to the nitrite functional group. The alkyl group is unreactive and the chemical and biological propertie ...
. This is a vasodilator that diminishes systolic murmurs in left-to-right shunts in ventricular septal defects. It also reveals right-to left shunts in the setting of pulmonic stenosis and a ventricular septal defect. * Methoxamine * Positioning of the patient. In the lateral decubitus position or lying on the left side. This will make murmurs in the mitral valve area more pronounced.


Anatomic sources

Systolic
Aortic valve stenosis Aortic stenosis (AS or AoS) is the narrowing of the exit of the left ventricle of the heart (where the aorta begins), such that problems result. It may occur at the aortic valve as well as above and below this level. It typically gets worse ove ...
is a crescendo/decrescendo systolic murmur. It is best heard at the right upper sternal border (aortic area). It sometimes radiates to the carotid arteries. In mild aortic stenosis, the crescendo-decrescendo is early peaking. Whereas in severe aortic stenosis, the crescendo is late-peaking. In severe cases, obliteration of the S2 heart sound may occur. Stenosis of
Bicuspid aortic valve Bicuspid aortic valve (aka BAV) is a form of heart disease in which two of the leaflets of the aortic valve fuse during development in the womb resulting in a two-leaflet (bicuspid) valve instead of the normal three-leaflet (tricuspid) valve. BA ...
is like the aortic valve stenosis heart murmur. But, one may hear a systolic ejection click after S1 in calcified bicuspid aortic valves. Symptoms tend to present between 40 and 70 years of age.
Mitral regurgitation Mitral regurgitation (MR), also known as mitral insufficiency or mitral incompetence, is a form of valvular heart disease in which the mitral valve is insufficient and does not close properly when the heart pumps out blood. Section: Valvular He ...
is a holosystolic murmur. One can best hear it at the apex location and it may radiate to the axilla or precordium. When associated with
mitral valve prolapse Mitral valve prolapse (MVP) is a valvular heart disease characterized by the displacement of an abnormally thickened mitral valve leaflet into the left atrium during systole. It is the primary form of myxomatous degeneration of the valve. There ar ...
, one may hear a systolic click. In this scenario, valsalva maneuver will decrease left ventricular preload. This will move the murmur onset closer to S1. Isometric handgrip will increase left ventricular afterload. This will increase murmur intensity. In acute severe mitral regurgitation, one may not hear a holosystolic murmur.
Pulmonary valve stenosis Pulmonary valve stenosis (PVS) is a heart valve disorder. Blood going from the heart to the lungs goes through the pulmonary valve, whose purpose is to prevent blood from flowing back to the heart. In pulmonary valve stenosis this opening is too ...
is a crescendo-decrescendo systolic murmur. One can hear it best at the left upper sternal border. It has association with a systolic ejection click that increases with inspiration. This finding results from an increased venous return to the right side of the heart. Pulmonary stenosis sometimes radiates to the left clavicle. Tricuspid valve regurgitation is a holosystolic murmur. It presents at the left lower sternal border with radiation to the left upper sternal border. One may see prominent v and c waves in the JVP (jugular venous pressure). The murmur will increase with inspiration.
Hypertrophic obstructive cardiomyopathy Hypertrophic cardiomyopathy (HCM, or HOCM when obstructive) is a condition in which the heart becomes thickened without an obvious cause. The parts of the heart most commonly affected are the interventricular septum and the ventricles. This r ...
(or hypertrophic subaortic stenosis) will be a systolic crescendo-decrescendo murmur. One can best hear it at the left lower sternal border. Valsalva maneuver will increase the intensity of the murmur. Going from squatting to standing will also increase the intensity of the murmur.
Atrial septal defect Atrial septal defect (ASD) is a congenital heart defect in which blood flows between the atria (upper chambers) of the heart. Some flow is a normal condition both pre-birth and immediately post-birth via the foramen ovale; however, when this d ...
will present with a systolic crescendo-decrescendo murmur. It is best heard at the left upper sternal border. This is the result of an increased volume going through the pulmonary valve. It has association with a fixed, split S2 and a right ventricular heave.
Ventricular septal defect A ventricular septal defect (VSD) is a defect in the ventricular septum, the wall dividing the left and right ventricles of the heart. The extent of the opening may vary from pin size to complete absence of the ventricular septum, creating one ...
(VSD) will present as a holosystolic murmur. One can hear it at the left lower sternal border. It has association with a palpable thrill, and increases with isometric handgrip. A right to left shunt (
Eisenmenger syndrome Eisenmenger syndrome or Eisenmenger's syndrome is defined as the process in which a long-standing left-to-right cardiac shunt caused by a congenital heart defect (typically by a ventricular septal defect, atrial septal defect, or less commonly, pa ...
) may develop with uncorrected VSDs. This is due to worsening pulmonary hypertension. Pulmonary hypertension will increase the murmur intensity and may present with cyanosis. Flow murmur presents at the right upper sternal border. It may present in certain conditions, such as anemia, hyperthyroidism, fever, and pregnancy. Diastolic Aortic valve regurgitation will present as a diastolic decrescendo murmur. One can hear it at the left lower sternal border. One may also hear it at the right lower sternal border (when associated with a dilated aorta). Other possible exam findings are bounding carotid and peripheral pulses. These are also known as Corrigan's pulse or
Watson's water hammer pulse Watson's water hammer pulse, also known as Corrigan's pulse or collapsing pulse, is the medical sign (seen in aortic regurgitation) which describes a pulse that is bounding and forceful, rapidly increasing and subsequently collapsing, as if it were ...
. Another possible finding is a widened
pulse pressure Pulse pressure is the difference between systolic and diastolic blood pressure. It is measured in millimeters of mercury (mmHg). It represents the force that the heart generates each time it contracts. Resting blood pressure is normally approx ...
.
Mitral stenosis Mitral stenosis is a valvular heart disease characterized by the narrowing of the opening of the mitral valve of the heart. It is almost always caused by rheumatic valvular heart disease. Normally, the mitral valve is about 5 cm2 during d ...
presents as a diastolic low-pitched decrescendo murmur. It is best heard at the cardiac apex in the left lateral decubitus position. Mitral stenosis may have an opening snap. Increasing severity will shorten the time between S2 (A2) and the opening snap. For example, in severe MS the opening snap will occur earlier after A2.
Tricuspid valve stenosis Tricuspid valve stenosis is a valvular heart disease that narrows the opening of the heart's tricuspid valve. It is a relatively rare condition that causes stenosis (increased restriction of blood flow through the valve). Cause Causes of tricuspi ...
presents as a diastolic decrescendo murmur. One can hear it at the left lower sternal border. One may see signs of
right heart failure Heart failure (HF), also known as congestive heart failure (CHF), is a syndrome, a group of signs and symptoms caused by an impairment of the heart's blood pumping function. Symptoms typically include shortness of breath, excessive fatigue, an ...
on exam. Pulmonary valve regurgitation presents as a diastolic decrescendo murmur. One may hear it at the left lower sternal border. A palpable S2 in the second left intercostal space correlates with pulmonary hypertension due to mitral stenosis. The cooing dove murmur is a cardiac murmur with a musical quality (high pitched). Associated with aortic valve regurgitation (or mitral regurgitation before rupture of chordae). It is a diastolic murmur heard over the mid-precordium. Continuous and Combined Systolic/Diastolic
Patent ductus arteriosus ''Patent ductus arteriosus'' (PDA) is a medical condition in which the ''ductus arteriosus'' fails to close after birth: this allows a portion of oxygenated blood from the left heart to flow back to the lungs by flowing from the aorta, which has ...
may present as a continuous murmur radiating to the back. Severe coarctation of the aorta can present with a continuous murmur. One may hear the systolic component at the left infraclavicular region and the back. This is due to the stenosis. One may hear the diastolic component over the chest wall. This is due to blood flow through collateral vessels. Acute severe aortic regurgitation may present with a three phase murmur. First, a midsystolic murmur followed by S2. Following this is a parasternal early diastolic and mid-diastolic murmur (
Austin Flint murmur In cardiology, an Austin Flint murmur is a low-pitched rumbling heart murmur which is best heard at the cardiac apex. It can be a mid-diastolicEric J. TopolThe Topol Solution: Textbook of Cardiovascular Medicine Third Edition with DVD, Plus Integra ...
). The exact cause of an Austin Flint murmur is unknown. Hypothesis is that the mechanism of murmur is from the severe aortic regurgitation. In severe aortic regurgitation the jet vibrates the anterior mitral valve leaflet. This causes collision with the mitral inflow during diastole. As such, the mitral valve orifice narrows. This results in increased mitral inflow velocity. This leads to the jet impinging on the myocardial wall. Ruptured aortic sinus (sinus of Valsalva) may present as a continuous murmur. This is an uncommon cause of continuous murmur One may hear it at the aortic area and along the left sternal border.


Types and disease associations

;Continuous machinery murmur, at the left upper sternal border :Classic for a
patent ductus arteriosus ''Patent ductus arteriosus'' (PDA) is a medical condition in which the ''ductus arteriosus'' fails to close after birth: this allows a portion of oxygenated blood from the left heart to flow back to the lungs by flowing from the aorta, which has ...
(PDA). Signs of infants associated with serious cases of PDA are poor feeding, failure to thrive and respiratory distress. Other examination findings may include widened pulse pressures and bounding pulses. A machinery murmur is also known as a Gibson murmur. ;Systolic murmur loudest below the left scapula :Classic for a coarctation of the aorta. Coarctation of the aorta is narrowing of the aorta. This can occur in Turner's Syndrome, (
gonadal dysgenesis Gonadal dysgenesis is classified as any congenital developmental disorder of the reproductive system in the male or female. It is the atypical development of the gonads in an embryo, with reproductive tissue replaced with functionless, fibrous ti ...
). Turner's Syndrome is an X-linked disorder with absence of one X-chromosome. Other exam findings of coarctation of the aorta include radio-femoral delay. This is when the femoral pulse is later than the radial pulse. The pulses in the lower extremity may be weaker than those of the upper extremity. Another exam finding is of varying blood pressure in the upper and lower extremities. This presents as higher blood pressure in the arms and lower blood pressure in the legs. ;Harsh holosystolic (pansystolic) murmur at the left lower sternal border :Classic for a ventricular septal defect (VSD). This may lead to the development of the delayed-onset cyanotic heart disease known as
Eisenmenger syndrome Eisenmenger syndrome or Eisenmenger's syndrome is defined as the process in which a long-standing left-to-right cardiac shunt caused by a congenital heart defect (typically by a ventricular septal defect, atrial septal defect, or less commonly, pa ...
.
Eisenmenger syndrome Eisenmenger syndrome or Eisenmenger's syndrome is defined as the process in which a long-standing left-to-right cardiac shunt caused by a congenital heart defect (typically by a ventricular septal defect, atrial septal defect, or less commonly, pa ...
is a reversal of the left-to-right heart shunt. This is the result of hypertrophy of the right ventricle over time. This causes a right-to-left heart shunt. The VSD allows deoxygenated blood to flow from the right to left side of the heart. This blood bypasses the lungs. The lack of oxygenation in the pulmonary circulation results in cyanosis. ;Widely split fixed S2 and systolic ejection murmur at the left upper sternal border :Classic for a
patent foramen ovale Atrial septal defect (ASD) is a congenital heart defect in which blood flows between the atria (upper chambers) of the heart. Some flow is a normal condition both pre-birth and immediately post-birth via the foramen ovale; however, when this d ...
(PFO) or
atrial septal defect Atrial septal defect (ASD) is a congenital heart defect in which blood flows between the atria (upper chambers) of the heart. Some flow is a normal condition both pre-birth and immediately post-birth via the foramen ovale; however, when this d ...
(ASD). A PFO is lack of closure of the
foramen ovale There are multiple structures in the human body with the name foramen ovale (plural: ''foramina ovalia''; Latin for "oval hole"): * Foramen ovale (heart), in the fetal heart, a shunt from the right atrium to left atrium * Foramen ovale (skull), at ...
. At first, this produces a left-to-right heart shunt. This does not produce cyanosis, but causes pulmonary hypertension. Longstanding uncorrected atrial septal defects can also result in
Eisenmenger syndrome Eisenmenger syndrome or Eisenmenger's syndrome is defined as the process in which a long-standing left-to-right cardiac shunt caused by a congenital heart defect (typically by a ventricular septal defect, atrial septal defect, or less commonly, pa ...
.
Eisenmenger syndrome Eisenmenger syndrome or Eisenmenger's syndrome is defined as the process in which a long-standing left-to-right cardiac shunt caused by a congenital heart defect (typically by a ventricular septal defect, atrial septal defect, or less commonly, pa ...
can result in cyanosis.


Management

A medical provider (e.g. doctor) may order tests for further evaluation of a heart murmur. The echocardiogram is a common test used. This is also known as an "echo" or ultrasound of the heart. It shows the heart structures and blood flow through the heart. Further testing is usually done when symptoms that may be of concern are present. The need for treatment depends on the diagnosis and severity. In some cases, the condition causing the heart murmur may prompt monitoring. Sometimes, heart murmurs disappear on their own. This happens when the cause of the heart murmur is no longer present. Monitoring will help determine how the condition changes. It may stay the same, worsen, or improve. In other cases, the condition causing the heart murmur may not prompt any further tests. Treatment ranges from medication to surgeries.


References


External links

{{DEFAULTSORT:Heart Murmur Heart murmurs Turbulence he:איוושה