Heart murmur


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.
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.
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.

Classification

Murmurs can be classified by seven different characteristics: timing, shape, location, radiation, intensity, pitch and quality.
A to remember what characteristics to look for when listening to murmurs is SCRIPT: Site, Configuration, 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 aortic stenoses are systolic while pulmonary and aortic insufficiency are diastolic. Mitral and tricuspid defects are opposite.

Interventions that change murmur sounds

Systolic
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 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 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 and sometimes radiates to the left clavicle.
Tricuspid valve regurgitation presents as a holosystolic 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. The murmur will increase with inspiration.
Hypertrophic obstructive cardiomyopathy 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 will present as a holosystolic murmur at the left lower sternal border, associated with a palpable thrill, and increases with isometric handgrip. A right to left shunt 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.
Diastolic
Aortic valve regurgitation will present as a diastolic decrescendo murmur heard at the left lower sternal border or right lower sternal border. This may be associated with bounding carotid and peripheral pulses, 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 and the opening snap.
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. 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.

Types and disease associations

;Continuous machinery murmur, at the left upper sternal border
;Systolic murmur loudest below the left scapula
;Harsh holosystolic murmur at the left lower sternal border
;Widely split fixed S2 and systolic ejection murmur at the left upper sternal border

Cooing dove murmur

The cooing dove murmur is a cardiac murmur with a musical quality and is associated with aortic valve regurgitation. It is a diastolic murmur which can be heard over the mid-precordium.