This article may be too technical for most readers to understand.April 2014) (Learn how and when to remove this template message)(
|Cardiac murmurs and other cardiac sounds|
|Auscultogram from normal and abnormal heart sounds|
Heart murmurs are heart sounds produced when blood is pumped across a heart valve and creates a sound loud enough to be heard with a stethoscope. Murmurs are of various types and are important in the detection of cardiac and valvular pathologies (can be a sign of Heart diseases or defects).
There are two types of murmurs. A functional murmur or "physiologic murmur" is a heart murmur that is primarily due to physiologic conditions outside the heart. Other types of murmurs are due to structural defects in the heart itself. Functional murmurs are benign (an "innocent murmur").
Murmurs may also be the result of various problems, such as narrowing or leaking of valves, or the presence of abnormal passages through which blood flows in or near the heart. Such murmurs, known as pathologic murmurs, should be evaluated by a cardiologist.
Heart murmurs are most frequently categorized by timing, into systolic heart murmurs and diastolic heart murmurs, differing in the part of the heartbeat on which they can be heard. However, continuous murmurs cannot be directly placed into either category.
Murmurs can be classified by seven different characteristics: timing, shape, location, radiation, intensity, pitch and quality.
A mnemonic to remember what characteristics to look for when listening to murmurs is SCRIPT: Site, Configuration (shape), Radiation, Intensity, Pitch and quality, and Timing in the cardiac cycle.
The use of two simple mnemonics may help differentiate systolic and diastolic murmurs; PASS and PAID. Pulmonary and aorticstenoses are systolic while pulmonary and aorticinsufficiency (regurgitation) are diastolic. Mitral and tricuspid defects are opposite.
Aortic valve stenosis typically is a crescendo/decrescendo systolic murmur best heard at the right upper sternal border sometimes with radiation to the carotid arteries. In mild aortic stenosis, the crescendo-decrescendo is early peaking whereas in severe aortic stenosis, the crescendo is late-peaking, and the S2 heart sound may be obliterated.
Stenosis of Bicuspid aortic valve is similar to the aortic valve stenosis heart murmur, but a systolic ejection click may be heard after S1 in calcified bicuspid aortic valves. Symptoms tend to present between 40 and 70 years of age.
Mitral regurgitation typically is a holosystolic (pansystolic) murmur heard best at the apex, and may radiate to the axilla or precordium. A systolic click may be heard if there is associated mitral valve prolapse. Valsalva maneuver in mitral regurgitation associated with mitral valve prolapse will decrease left ventricular preload and move the murmur onset closer to S1, and isometric handgrip, which increases left ventricular afterload, will increase murmur intensity. In acute severe mitral regurgitation, a holosystolic (pansystolic) murmur may not be heard.
Pulmonary valve stenosis typically is a crescendo-decrescendo systolic murmur heard best at the left upper sternal border, associated with a systolic ejection click that increases with inspiration (due to increased venous return to the right side of the heart) and sometimes radiates to the left clavicle.
Tricuspid valve regurgitation presents as a holosystolic (pansystolic) murmur at the left lower sternal border with radiation to the left upper sternal border. Prominent v and c waves may be seen 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 best heard at the left lower sternal border. Valsalva maneuver will increase the intensity of the murmur, as will changing positions from squatting to standing.
Atrial septal defect will present with a systolic crescendo-decrescendo murmur best heard at the left upper sternal border due to increased volume going through the pulmonary valve, and is associated with a fixed, split S2 and a right ventricular heave.
Ventricular septal defect (VSD) will present as a holosystolic (pansystolic) murmur at the left lower sternal border, associated with a palpable thrill, and increases with isometric handgrip. A right to left shunt (Eisenmenger syndrome) may develop with uncorrected VSDs due to worsening pulmonary hypertension, which will increase the murmur intensity and be associated with cyanosis.
Flow murmur may be heard at the right upper sternal border in certain conditions, such as anemia, hyperthyroidism, fever, and pregnancy.
Aortic valve regurgitation will present as a diastolic decrescendo murmur heard at the left lower sternal border or right lower sternal border (when associated with a dilated aorta). This may be associated with bounding carotid and peripheral pulses (Corrigan's pulse, Watson's water hammer pulse), and a widened pulse pressure.
Mitral stenosis typically presents as a diastolic low-pitched decrescendo murmur best heard at the cardiac apex in the left lateral decubitus position. It may be associated with an opening snap. Increasing severity will shorten the time between S2(A2) and the opening snap. (i.e. In severe MS the opening snap will occur earlier after A2)
Tricuspid valve stenosis presents as a diastolic decrescendo murmur at the left lower sternal border, and signs of right heart failure may be seen on exam.
Pulmonary valve regurgitation presents as a diastolic decrescendo murmur at the left lower sternal border. A palpable S2 in the second left intercostal space correlates with pulmonary hypertension due to mitral stenosis.
Continuous and Combined Systolic/Diastolic
Patent ductus arteriosus may present as a continuous murmur radiating to the back.
Severe coarctation of the aorta can present with a continuous murmur: a systolic component at the left infraclavicular region and the back due to the stenosis, and a diastolic component over the chest wall due to blood flow through collateral vessels.
Acute severe aortic regurgitation is associated with a three phase murmur, specifically a midsystolic murmur followed by S2, followed by a parasternal early diastolic and mid-diastolic murmur (Austin Flint murmur). Although the exact cause of an Austin Flint murmur is unknown, it is hypothesized that the mechanism of murmur is from the severe aortic regurgitation jet vibrating the anterior mitral valve leaflet, colliding with the mitral inflow during diastole, with increased mitral inflow velocity from the narrowed mitral valve orifice leading to the jet impinging on the myocardial wall.
Another uncommon cause of a continuous murmur is a ruptured sinus of valsalva.Usually the murmur is well heard in the aortic area and along the left sternal border.
The cooing dove murmur is a cardiac murmur with a musical quality (high pitched - hence the name) and is associated with aortic valve regurgitation (or mitral regurgitation before rupture of chordae). It is a diastolic murmur which can be heard over the mid-precordium.
Aortic stenosis is the narrowing of the exit of the left ventricle of the heart, such that problems result. It may occur at the aortic valve as well as above and below this level. It typically gets worse over time. Symptoms often come on gradually with a decreased ability to exercise often occurring first. If heart failure, loss of consciousness, or heart related chest pain occur due to AS the outcomes are worse. Loss of consciousness typically occurs with standing or exercising. Signs of heart failure include shortness of breath especially when lying down, at night, or with exercise, and swelling of the legs. Thickening of the valve without narrowing is known as aortic sclerosis.
A heart valve is a one-way valve that normally allows blood to flow in only one direction through the heart. The four valves are commonly represented in a mammalian heart that determines the pathway of blood flow through the heart. A heart valve opens or closes incumbent on 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.
A ventricle is one of two large chambers toward the bottom of the heart that collect and expel blood received from an atrium towards the peripheral beds within the body and lungs. The atrium primes the pump.
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 valve stenosis is a condition in which the canal between the left atrium and ventricle is narrowed due to disease of the cusps of the left atrioventricular (mitral) valve. Mitral valve stenosis may remain asymptomatic for years. When clinical symptoms develop, they may be similar to those of other heart diseases.
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 common ventricle. The ventricular septum consists of an inferior muscular and superior membranous portion and is extensively innervated with conducting cardiomyocytes.
Mitral regurgitation (MR), mitral insufficiency, or mitral incompetence is a form of valvular heart disease in which the mitral valve does not close properly when the heart pumps out blood. It is the abnormal leaking of blood backwards from the left ventricle, through the mitral valve, into the left atrium, when the left ventricle contracts, i.e. there is regurgitation of blood back into the left atrium. MR is the most common form of valvular heart disease.
Ebstein's anomaly is a congenital heart defect in which the septal and posterior leaflets of the tricuspid valve are displaced towards the apex of the right ventricle of the heart. It is classified as a critical congenital heart defect accounting for <1% of all congenital heart defects presenting in ≈1 per 200,000 live births.
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.
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.
Tricuspid insufficiency (TI), more commonly called tricuspid regurgitation (TR), is a type of valvular heart disease in which the tricuspid valve of the heart, located between the right atrium and right ventricle, does not close completely when the right ventricle contracts (systole). TR allows the blood to flow backwards from the right ventricle to the right atrium, which increases the volume and pressure of the blood both in the right atrium and the right ventricle, which may increase central venous volume and pressure if the backward flow is sufficiently severe.
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 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.