Heart murmurs are unique heart sounds produced when blood flows across a heart valve or blood vessel.[1] This occurs when turbulent blood flow creates a sound loud enough to hear with a stethoscope.[2] Turbulent blood flow is not smooth.[3] The sound differs from normal heart sounds by their characteristics. For example, heart murmurs may have a distinct pitch, duration and timing.[2][4] The major way health care providers examine the heart on physical exam is heart auscultation;[4] another clinical technique is palpation, which can detect by touch when such turbulence causes the vibrations called cardiac thrill.[5] A murmur is a sign found during the cardiac exam. 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 is a benign heart murmur that is primarily due to physiologic conditions outside the heart. The other type of heart murmur is due to a structural defect in the heart itself.[1][6] 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.[1]
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.[4]
Heart murmurs are frequently categorized by timing. These include systolic heart murmurs, diastolic heart murmurs, 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.[7]
Heart sounds of a 16-year-old girl diagnosed with mitral valve prolapse and mitral regurgitation. Auscultating her heart, a systolic murmur and click are heard. Recorded with the stethoscope over the mitral valve.
Heart sounds of a healthy 17 year old female. An innocent systolic flow murmur is audible, as well as the normal splitting of S2 on inspiration. Recorded with the stethoscope at tricuspid.
Shape refers to the intensity over time. Murmurs can be crescendo, decrescendo 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.[4] Health care providers listen to these areas with a stethoscope.
Position for auscultation: 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.[4] 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. Also, this will help to hear extra heart sounds (S3 or S4).[4]
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.[4]
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, from 1 to 6:[9][10]
Levine scale
Murmur Description
1
Only audible on listening carefully for some time
2
Faint but immediately audible on placing the stethoscope on the chest
3
Loud, readily audible but with no palpable thrill.[11]
4
loud with a palpable thrill
5
loud with a palpable thrill. So loud that it is audible with only the rim of the stethoscope touching the chest.
6
loud with a palpable thrill. Audible with the stethoscope not touching the chest but lifted just off it.
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 leads to an increase in intrathoracic negative pressure. This increases the capacity of pulmonary circulation, 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.[12][13] Positive Carvallo's sign describes the increase in intensity of a tricuspid regurgitation murmur heard with inspiration.[14]
Squatting, by increasing afterload and increasing preload. Squatting leads to an increase in systemic vascular resistance. 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. Valsalva maneuver has utility in detecting hypertrophic obstructive cardiomyopathy (HOCM). According to one study, it has a sensitivity of 65% and specificity of 96% in HOCM.[12] 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.[15]
Inhaled amyl nitrite. 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.[16]
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.
Aortic valve stenosis 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 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 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, 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 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 (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 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 (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) 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.
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. Another possible finding is a widened pulse pressure.
Mitral stenosis 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.
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.[17]
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). 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.[18][19]
Ruptured aortic sinus (sinus of Valsalva) may present as a continuous murmur. This is an uncommon cause of continuous murmur[20] 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 (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.[21]
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). 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 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
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.[1] 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.[1] 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.[1] 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.
Related Research Articles
A heart valve is a biological one-way valve that allows blood to flow in one direction through the chambers of the heart. Four valves are usually present in a mammalian heart and together they determine the pathway of blood flow through the heart. A heart valve opens or closes according to differential blood pressure on each side.
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 stethoscope to listen for these unique and distinct sounds that provide important auditory data regarding the condition of the heart.
The mitral valve, also known as the bicuspid valve or left atrioventricular valve, is one of the four heart valves. It has two cusps or flaps and lies between the left atrium and the left ventricle of the heart. The heart valves are all one-way valves allowing blood flow in just one direction. The mitral valve and the tricuspid valve are known as the atrioventricular valves because they lie between the atria and the ventricles.
A ventricle is one of two large chambers located toward the bottom of the heart that collect and expel blood towards the peripheral beds within the body and lungs. The blood pumped by a ventricle is supplied by an atrium, an adjacent chamber in the upper heart that is smaller than a ventricle. Interventricular means between the ventricles, while intraventricular means within one ventricle.
Afterload is the pressure that the heart must work against to eject blood during systole. Afterload is proportional to the average arterial pressure. As aortic and pulmonary pressures increase, the afterload increases on the left and right ventricles respectively. Afterload changes to adapt to the continually changing demands on an animal's cardiovascular system. Afterload is proportional to mean systolic blood pressure and is measured in millimeters of mercury.
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 diastole. Any decrease in area below 2 cm2 causes mitral stenosis. Early diagnosis of mitral stenosis in pregnancy is very important as the heart cannot tolerate increased cardiac output demand as in the case of exercise and pregnancy. Atrial fibrillation is a common complication of resulting left atrial enlargement, which can lead to systemic thromboembolic complications such as stroke.
Aortic regurgitation (AR), also known as aortic insufficiency (AI), is the leaking of the aortic valve of the heart that causes blood to flow in the reverse direction during ventricular diastole, from the aorta into the left ventricle. As a consequence, the cardiac muscle is forced to work harder than normal.
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. It is the abnormal leaking of blood backwards – regurgitation from the left ventricle, through the mitral valve, into the left atrium, when the left ventricle contracts. Mitral regurgitation is the most common form of valvular heart disease.
A transthoracic echocardiogram (TTE) is the most common type of echocardiogram, which is a still or moving image of the internal parts of the heart using ultrasound. In this case, the probe is placed on the chest or abdomen of the subject to get various views of the heart. It is used as a non-invasive assessment of the overall health of the heart, including a patient's heart valves and degree of heart muscle contraction. The images are displayed on a monitor for real-time viewing and then recorded.
Valvular heart disease is any cardiovascular disease process involving one or more of the four valves of the heart. These conditions occur largely as a consequence of aging, but may also be the result of congenital (inborn) abnormalities or specific disease or physiologic processes including rheumatic heart disease and pregnancy.
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 indication and integrated with other examinations especially the respiratory examination.
Right ventricular hypertrophy (RVH) is a condition defined by an abnormal enlargement of the cardiac muscle surrounding the right ventricle. The right ventricle is one of the four chambers of the heart. It is located towards the lower-end of the heart and it receives blood from the right atrium and pumps blood into the lungs.
Lutembacher's syndrome is a very rare form of congenital heart disease that affects one of the chambers of the heart as well as a valve. It is commonly known as both congenital atrial septal defect (ASD) and acquired mitral stenosis (MS). Congenital atrial septal defect refers to a hole being in the septum or wall that separates the two atria; this condition is usually seen in fetuses and infants. Mitral stenosis refers to mitral valve leaflets sticking to each other making the opening for blood to pass from the atrium to the ventricles very small. With the valve being so small, blood has difficulty passing from the left atrium into the left ventricle. Septal defects that may occur with Lutembacher's syndrome include: Ostium primum atrial septal defect or ostium secundum which is more prevalent.
The following outline is provided as an overview of and topical guide to cardiology, the branch of medicine dealing with disorders of the human heart. The field includes medical diagnosis and treatment of congenital heart defects, coronary artery disease, heart failure, valvular heart disease and electrophysiology. Physicians who specialize in cardiology are called cardiologists.
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.
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.
The E/A ratio is a marker of the function of the left ventricle of the heart. It represents the ratio of peak velocity blood flow from left ventricular relaxation in early diastole to peak velocity flow in late diastole caused by atrial contraction. It is calculated using Doppler echocardiography, an ultrasound-based cardiac imaging modality. Abnormalities in the E/A ratio suggest that the left ventricle, which pumps blood into the systemic circulation, cannot fill with blood properly in the period between contractions. This phenomenon is referred to as diastolic dysfunction and can eventually lead to the symptoms of heart failure.
The handgrip maneuver is performed by clenching one's fist forcefully for a sustained time until fatigued. Variations include squeezing an item such as a rolled up washcloth.
1 2 Braunwald's heart disease: a textbook of cardiovascular medicine. Douglas P. Zipes, Peter Libby, Robert O. Bonow, Douglas L. Mann, Gordon F. Tomaselli, Eugene Braunwald (Eleventhed.). Philadelphia. 2019. ISBN978-0-323-46342-3. OCLC1030994993.{{cite book}}: CS1 maint: location missing publisher (link) CS1 maint: others (link)
↑ Hurst's the heart. Valentin Fuster, Robert A. Harrington, Jagat Narula, Zubin J. Eapen (14thed.). New York. 2017. ISBN9780071843249. OCLC976001975.{{cite book}}: CS1 maint: location missing publisher (link) CS1 maint: others (link)
1 2 3 4 5 6 7 Bickley, Lynn S. (2021). Bates' guide to physical examination and history taking. Peter G. Szilagyi, Richard M. Hoffman, Rainier P. Soriano (Thirteenthed.). Philadelphia. ISBN978-1-4963-9817-8. OCLC1153338113.{{cite book}}: CS1 maint: location missing publisher (link)
↑ Orient JM (2010). "Chapter 17: The Heart". Sapira's Art & Science of Bedside Diagnosis (4thed.). Philadelphia: Wolters Kluwers Health. p.339. ISBN978-1-60547-411-3.
↑ Freeman AR, Levine SA (1933). "Clinical significance of systolic murmurs: Study of 1000 consecutive "noncardiac" cases". Ann Intern Med. 6 (11): 1371–1379. doi:10.7326/0003-4819-6-11-1371.
↑ Maisel A, Atwood J, Goldberger A (1984). "Hepatojugular reflux: useful in the bedside diagnosis of tricuspid regurgitation". Ann Intern Med. 101 (6): 781–2. doi:10.7326/0003-4819-101-6-781. PMID6497192.
↑ Harrison's Internal Medicine 17th, chapter 5, "Disorders of the cardiovascular system," question 32, self assessment and board review
↑ Harrison's Internal Medicine 17th, chapter 5, "Disorders of the cardiovascular system," question 86-87, self assessment and board review
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