Murmurs

Murmurs: Excerpt from Professional Guide to Signs & Symptoms (Fifth Edition)

Murmurs are auscultatory sounds heard within the heart chambers or major arteries. They’re classified by their timing and duration in the cardiac cycle, auscultatory location, loudness, configuration, pitch, and quality.

Timing can be characterized as systolic (between S₁ and S₂), holosystolic (continuous throughout systole), diastolic (between S₂ and S₁), or continuous throughout systole and diastole; systolic and diastolic murmurs can be further characterized as early, middle, or late.

Locationrefers to the area of maximum loudness, such as the apex, the lower left sternal border, or an intercostal space. Loudnessisgraded on a scale of 1 to 6. A grade 1 murmur is very faint, only detected after careful auscultation. A grade 2 murmur is a soft, evident murmur. Murmurs considered to be grade 3 are moderately loud. A grade 4 murmur is a loud murmur with a possible intermittent thrill. Grade 5 murmurs are loud and associated with a palpable precordial thrill. Grade 6 murmurs are loud and, like grade 5 murmurs, are associated with a thrill. A grade 6 murmur is audible even when the stethoscope is lifted from the thoracic wall.

Configuration, or shape, refers to the nature of loudness—crescendo (grows louder), decrescendo (grows softer), crescendo-decrescendo (first rises, then falls), decrescendo-crescendo (first falls, then rises), plateau (even intensity), or variable (uneven intensity). The murmur’s pitch may be high or low. Its quality may be described as harsh, rumbling, blowing, scratching, buzzing, musical, or squeaking.

Murmurs can reflect accelerated blood flow through normal or abnormal valves; forward blood flow through a narrowed or irregular valve or into a dilated vessel; blood backflow through an incompetent valve, septal defect, or patent ductus arteriosus; or decreased blood viscosity. Commonly the result of organic heart disease, murmurs occasionally may signal an emergency situation—for example, a loud holosystolic murmur after an acute myocardial infarction (MI) may signal papillary muscle rupture or ventricular septal defect. Murmurs may also result from surgical implantation of a prosthetic valve. (See When murmurs mean emergency.)

Some murmurs are innocent, or functional. An innocent systolic murmur is generally soft, medium-pitched, and loudest along the left sternal border at the second or third intercostal space. It’s exacerbated by physical activity, excitement, fever, pregnancy, anemia, or thyrotoxicosis. Examples include Still’s murmur in children and mammary souffle, often heard over either breast during late pregnancy and early postpartum. (See Detecting congenital murmurs.)  

History and physical examination

If you discover a murmur, try to determine its type through careful auscultation. (See Identifying common murmurs, page 517.) Use the bell of your stethoscope for low-pitched murmurs; the diaphragm for high-pitched murmurs.

Next, obtain a patient history. Ask if the murmur is a new discovery, or if it has been known since birth or childhood. Find out if the patient has experienced any associated symptoms, particularly palpitations, dizziness, syncope, chest pain, dyspnea, and fatigue. (See Differential diagnosis: Murmurs, pages 518 and 519.) Explore the patient’s medical history, noting especially any incidence of rheumatic fever, recent dental work, heart disease, or heart surgery, particularly prosthetic valve replacement.

Perform a systematic physical examination. Note especially the presence of cardiac arrhythmias, jugular vein distention, and such pulmonary signs and symptoms as dyspnea, orthopnea, and crackles. Is the patient’s liver tender or palpable? Does he have peripheral edema?

Medical causes

Aortic insufficiency

Acute aortic insufficiency typically produces a soft, short diastolic murmur over the left sternal border that’s best heard when the patient sits and leans forward and at the end of a forced held expiration. S₂ may be soft or absent. Sometimes, a soft, short midsystolic murmur may also be heard over the second right intercostal space. Associated findings include tachycardia, dyspnea, jugular vein distention, crackles, increased fatigue, and pale, cool extremities.

Chronic aortic insufficiency causes a high-pitched, blowing, decrescendo diastolic murmur that’s best heard over the second or third right intercostal space or the left sternal border with the patient sitting, leaning forward, and holding his breath after deep expiration. An Austin Flint murmur—a rumbling, mid-to-late diastolic murmur best heard at the apex—may also occur. Complications may not develop until ages 40 to 50; then, typical findings include palpitations, tachycardia, angina, increased fatigue, dyspnea, orthopnea, and crackles.

Aortic stenosis

With this valvular disorder, the murmur is systolic, beginning after S₁ and ending at or before aortic valve closure. It’s harsh and grating, medium-pitched, and crescendo-decrescendo. Loudest over the second right intercostal space when the patient is sitting and leaning forward, this murmur may also be heard at the apex, at the suprasternal notch (Erb’s point), and over the carotid arteries.

If the patient has advanced disease, S₂ may be heard as a single sound, with inaudible aortic closure. An early systolic ejection click at the apex is typical but is absent when the valve is severely calcified. Associated signs and symptoms usually don’t appear until age 30 in congenital aortic stenosis, ages 30 to 65 in stenosis due to rheumatic disease, and after age 65 in calcific aortic stenosis. They may include dizziness, syncope, dyspnea on exertion, paroxysmal nocturnal dyspnea, fatigue, and angina.

Cardiomyopathy (hypertrophic)

This disorder generates a harsh late systolic murmur, ending at S₂. Best heard over the left sternal border and at the apex, the murmur is commonly accompanied by an audible S₃or S₄. The murmur decreases with squatting and increases with sitting down. Major associated symptoms are dyspnea and chest pain; palpitations, dizziness, and syncope may also occur.

Mitral insufficiency

Acute mitral insufficiency is characterized by a medium-pitched blowing, early systolic or holosystolic decrescendo murmur at the apex, along with a widely split S₂ and commonly an S₄. This murmur doesn’t get louder on inspiration as with tricuspid insufficiency. Associated findings typically include tachycardia and signs of acute pulmonary edema.

Chronic mitral insufficiency produces a high-pitched, blowing, holosystolic plateau murmur that’s loudest at the apex and usually radiates to the axilla or back. Fatigue, dyspnea, and palpitations may also occur.

Mitral prolapse

This disorder generates a midsystolic to late-systolic click with a high-pitched late-systolic crescendo murmur, best heard at the apex. Occasionally, multiple clicks may be heard, with or without a systolic murmur. Associated findings include cardiac awareness, migraine headaches, dizziness, weakness, syncope, palpitations, chest pain, dyspnea, severe episodic fatigue, mood swings, and anxiety.

Mitral stenosis

With this valvular disorder, the murmur is soft, low-pitched, rumbling, crescendo-decrescendo, and diastolic, accompanied by a loud S₁ or an opening snap—a cardinal sign. It’s best heard at the apex with the patient in the left lateral position. Mild exercise will help make this murmur audible.

With severe stenosis, the murmur of mitral insufficiency may also be heard. Other findings include hemoptysis, exertional dyspnea and fatigue, and signs of acute pulmonary edema.

Myxomas

A left atrial myxoma (most common) usually produces a middiastolic murmur and a holosystolic murmur that’s loudest at the apex, with an S₄, an early diastolic thudding sound (tumor plop), and a loud, widely split S₁.Related features include dyspnea, orthopnea, chest pain, fatigue, weight loss, and syncope.

A right atrial myxoma causes a late diastolic rumbling murmur, a holosystolic crescendo murmur, and tumor plop, best heard at the lower left sternal border. Other findings include fatigue, peripheral edema, ascites, and hepatomegaly.

A left ventricular myxoma (rare) produces a systolic murmur, best heard at the lower left sternal border, arrhythmias, dyspnea, and syncope.

A right ventricular myxoma commonly generates a systolic ejection murmur with delayed S₂ and a tumor plop, best heard at the left sternal border. It’s accompanied by peripheral edema, hepatomegaly, ascites, dyspnea, and syncope.

Papillary muscle rupture

With this life-threatening complication of an acute MI, a loud holosystolic murmur can be auscultated at the apex. Related findings include severe dyspnea, chest pain, syncope, hemoptysis, tachycardia, and hypotension.

Rheumatic fever with pericarditis

A pericardial friction rub along with murmurs and gallops are heard best with the patient leaning forward on his hands and knees during forced expiration. The most common murmurs heard are the systolic murmur of mitral insufficiency, a midsystolic murmur due to swelling of the leaflet of the mitral valve, and the diastolic murmur of aortic insufficiency. Other signs and symptoms include fever, joint and sternal pain, edema, and tachypnea.

Tricuspid insufficiency

This valvular abnormality is characterized by a soft, high-pitched, holosystolic blowing murmur that increases with inspiration (Carvallo’s sign), decreases with exhalation and Valsalva’s maneuver, and is best heard over the lower left sternal border and the xiphoid area. Following a lengthy asymptomatic period, exertional dyspnea and orthopnea may develop, along with jugular vein distention, ascites, peripheral cyanosis and edema, muscle wasting, fatigue, weakness, and syncope.

Tricuspid stenosis

This valvular disorder produces a diastolic murmur similar to that of mitral stenosis, but louder with inspiration and decreased with exhalation and Valsalva’s maneuver. S₁ may also be louder. Associated signs and symptoms include fatigue, syncope, peripheral edema, jugular vein distention, ascites, hepatomegaly, and dyspnea.

Other causes

Treatments

Prosthetic valve replacement may cause variable murmurs, depending on the location, valve composition, and method of operation.

Special considerations

Prepare the patient for diagnostic tests, such as electrocardiography, echocardiography, and angiography. Administer an antibiotic and an anticoagulant as appropriate. Because any cardiac abnormality is frightening to the patient, provide emotional support.

Pediatric pointers

Innocent murmurs, such as Still’s murmur, are commonly heard in young children and typically disappear in puberty. Pathognomonic heart murmurs in infants and young children usually result from congenital heart disease, such as atrial and ventricular septal defects. Other murmurs can be acquired, as with rheumatic heart disease.

Patient counseling

Instruct the patient to contact his physician before undergoing invasive procedures or dental work because prophylactic antibiotics may be necessary.

Pictures

Book Source Details

• Book Title: Professional Guide to Signs & Symptoms (Fifth Edition)
• Author(s): Springhouse
• Year of Publication: 2006
• Copyright Details: Professional Guide to Signs & Symptoms (Fifth Edition), Copyright © 2006 Lippincott Williams & Wilkins.

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More About This Book: Title: Professional Guide to Signs & Symptoms (Fifth Edition) Authors: Springhouse Publisher: Lippincott Williams & Wilkins Copyright: 2006 ISBN: 1-58255-510-9

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