Murmurs are extra heart sounds that are produced as a result of turbulent blood flow which is sufficient to produce audible noise. Murmurs may be present in normal hearts without any heart disease. These types of murmurs, often referred to as innocent murmurs, usually cause no trouble for the patient.^[1] 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 an expert.

[edit] Classification

Murmurs can be classified by seven different characteristics: timing, shape, location, radiation, intensity, pitch and quality.^[2]

• Timing refers to whether the murmur is a systolic or diastolic murmur.
• Shape refers to the intensity over time; murmurs can be crescendo, decrescendo or crescendo-decrescendo.
• Location refers to where the heart murmur is auscultated best. There are 6 places on the anterior chest to listen for heart murmurs; the first five out of six are adjacent to the sternum. Each of these locations roughly correspond to a specific part of the heart. The locations are: 2nd right intercostal space, 2nd - 5th left intercostal spaces, and 5th mid-clavicular intercostal space.
• Radiation refers to where the sound of the murmur radiates. The general rule of thumb is that the sound radiates in the direction of the blood flow.
• Intensity refers to the loudness of the murmur, and is graded on a scale from 0-6/6.
• The pitch of a murmur is low, medium or high and is determined by whether it can be auscultated best with the bell or diaphragm of a stethoscope.
• Some examples of the quality of a murmur are: blowing, harsh, rumbling and musical.

[edit] Continuous murmurs

Heart murmurs are most frequently organized by timing, into systolic heart murmurs and diastolic heart murmurs. However, continuous murmurs can not be directly placed into either category.^[3]

[edit] Grading of murmurs

[edit] Interventions that change murmur sounds

• Inhalation will increase the amount of blood filling into the right ventricle, thereby prolonging ejection time. This will affect the closure of the pulmonary valve. This finding, also called Carvallo's Maneuver,has been found by studies to have a sensitivity of 100% and a specificity of 80% to 88% in detecting murmurs originating in the right heart ^{[5] [6]}.
• abrupt standing
• squatting
• valsalva maneuver. One study found the valsalva maneuver to have a sensitivity of 65%, specificity of 96% in detecting Hypertrophic obstructive cardiomyopathy (HOCM) ^[5].
• hand grip
• post ectopic potentiation
• amyl nitrite
• methoxamine
• positioning of the patient. ie. positioning patients in the left lateral position will allow a murmur in the mitral valve area to be more pronounced.

[edit] Examples of anatomic source of murmur

Stenosis of Bicuspid aortic valve

Symptoms tend to present between 40 and 70 years of age.

Stenosis of TriCuspid Aortic Valve

Symptoms more likely to present after 80 years of age.

Hypertrophic subaortic stenosis

Symptoms are a harsh murmur in mid-systole, often accompanied by S4, Brisk Bifid Carotid upstroke. Murmur increases with standing and valsalva maneuver.

Ventral septal defect

Symptoms are holosystolic, heard best at left lower sternal border.

[edit] See also

• Benign paediatric heart murmur
• Precordial examination

[edit] References

[edit] External links

• Information on heart murmurs in children from Seattle Children's Heart Center
• Heart Murmurs in Pediatric Patients
• The Auscultation Assistant Provides recordings of heart murmurs.