Definition
A murmur is turbulent blood flow through the heart as a result of one or more of the following etiologies:
A.Narrow valve opening, stenosis.
B.Incomplete valve closure, regurgitant or insufficient blood flow.
C.Abnormal opening through chambers, atrial or ventricular septal defect.
D.Rapid blood flow through normal valve structures; occurs during pregnancy, with increased physiologic demand states, such as thyrotoxicosis.
E.No abnormality; occurs in patients with thin chest walls.
Incidence
A.Innocent heart murmurs are quite common. They affect 40% to 45% of children and about 10% of adults at some point during their lifetimes. Innocent heart murmurs are more common in women during pregnancy. Abnormal heart murmurs occur most often in people who have certain heart conditions, such as a defective heart valve (e.g., aortic stenosis, mitral regurgitation).
Pathogenesis
A.Pathogenesis depends on specific etiology, but rheumatic heart disease, calcific changes, ischemic insults, congenital abnormalities, and degenerative diseases can all contribute to the development of a murmur.
Common Complaints
A.Often no symptoms are present, and murmur is found on routine examination.
B.Complaints with advanced valvular disease:
1.Chest pain.
2.Dyspnea.
3.Palpitations.
4.Shortness of breath (SOB).
5.Exercise intolerance.
6.Postural lightheadedness.
Subjective Data
A.Has the patient ever been diagnosed with a murmur?
B.Did the patient have frequent strep infections as a child?
C.Ask the patient about any recent viral infections.
D.Question the patient about chest pain; SOB; palpitations; diaphoresis; lightheadedness; or syncope, especially with exertion.
E.Ask the patient if any family members had sudden cardiac death before age 55.
Physical Examination
A.Check temperature, if indicated, pulse, respirations, and blood pressure (BP).
B.Inspect the chest for lifts and heaves.
C.Palpate the chest for lifts, heaves, and thrills.
D.Auscultate:
1.Auscultate heart for splitting of heart sounds, clicks, rubs, and murmurs; use bell and diaphragm of stethoscope to auscultate patient in left lateral, supine, standing, sitting (and leaning forward), and squatting positions and after having patient run in place or do jumping jacks for 2 to 3 minutes:
a.A new, systolic, regurgitant murmur in the setting of an acute myocardial infarction (MI) may indicate a ruptured papillary muscle and possible cardiogenic shock.
b.When a new murmur is audible, differentiate location, timing, quality, intensity, and duration. Note if radiation to neck, axilla, or back is present.
c.Note location of murmur:
i.Aortic: Second right intercostal space (ICS) next to sternum.
ii.Pulmonic: Second left ICS next to sternum.
iii.Tricuspid: Fifth left ICS next to sternum.
iv.Mitral: Fifth left ICS at midclavicular line.
d.If murmur is heard, have the patient squat, stand, and/or perform the Valsalva maneuver. Squatting will increase the blood to the heart and increase the left ventricle blood volume and stroke volume, which will increase the sound of the murmur. Standing and the Valsalva maneuver will provide the opposite, in which the venous return will drop and decrease the ventricle size and stroke volume and soften the sound of the murmur.
e.If the sound of the murmur occurs in the opposite action, softer when squatting and louder when standing or during the Valsalva maneuver, consider hypertrophic cardiomyopathy or mitral valve prolapse (MVP) as the diagnosis.
2.Auscultate the neck and axilla for radiation.
Diagnostic Tests
A.ECG.
B.Echocardiogram.
C.Chest radiography.
Differential Diagnoses
Major differentiation should be in the description of murmur, as this aids in identification of the murmur.
A.Timing:
1.Identify when the murmur occurs in the cardiac cycle.
2.Systolic murmurs may or may not be normal:
a.Occurs between the S1
lub and the S2
dub.
3.Diastolic murmurs are always abnormal:
a.Occurs between the S2
dub and the S1
lub.
B.Quality: Is the sound harsh, blowing, musical, rumbling, vibratory, or soft?
C.Intensity: Murmurs are usually graded on a six-point scale:
1.Grade I: Barely audible.
2.Grade II: Audible but soft.
3.Grade III: Easily audible without thrill.
4.Grade IV: Easily audible, thrill usually palpable.
5.Grade V: Audible with only the rim of the stethoscope on the chest wall.
6.Grade VI: Audible with the stethoscope barely off the chest wall; thrill present.
D.Duration: Identify location and timing in the specific phase of the cardiac cycle:
1.Holosystolic: Throughout systole.
2.Holodiastolic: Throughout diastole.
3.Midsystolic: Midway between S1 and S3.
4.Mid-diastolic: Midway between S2 and S1.
5.Decrescendo: Starts loud at the beginning, then tapers off.
6.Crescendo: Starts soft at the beginning, then gets louder.
E.Radiation: Murmur can be heard in another place, such as the neck, back, left axilla, or across precordium. Sound usually radiates in the direction of blood flow.
F.Location: Identify location on chest wall where murmur is heard the best. Identify site: Apex, pulmonary area, tricuspid, and aortic areas. Radiation murmur may also include axilla, left fourth ICS, or base of heart.
G.Configuration: The intensity of the murmur over time: Does it plateau, crescendo, decrescendo, or crescendodecrescendo?
H.Systolic murmurs: Systolic murmurs are benign or pathologic:
1.Early systolic murmurs:
a.Mitral regurgitation: Holosystolic, blowing may be loud. Located at fifth ICS and radiates to left axilla/back. Heard best in left lateral position and sudden squatting; intensity decreases with the Valsalva maneuver and standing.
b.Tricuspid regurgitation: Holosystolic, heard left lower sternal border or apex when right ventricle is enlarged. Intensity increases with inspiration and decreases with expiration. Straight leg raises may increase intensity. May also see hepatojugular reflux (HJR).
c.Physiologic: Early to midsystolic, low-pitch normal S1 to S2, located at left lower sternal edge at third to fourth ICS. Heard best with bell and supine and disappears when sitting up or holding breath. Commonly seen in pregnancy and infection.
2.Midsystolic to late systolic murmurs:
a.Aortic stenosis: Loud, hard crescendo-decrescendo at second right ICS and radiates to neck. Heard best leaning forward, increases with leg raise and lying flat. Decreases with Valsalva and handgrip standing.
b.Pulmonic stenosis: Prolonged, loud S2 or crescendo-decrescendo, usually greater than 3/6 at second ICS and radiates to neck; increases with inspiration.
c.Hypertrophic cardiomyopathy (aortic outflow obstruction): Peaks at midsystole; loud, harsh tone at left, lower sternal border that may radiate to neck. Increases with Valsalva maneuver and standing, decreases with sudden squatting. Note carotid upstroke brisk.
3.Late systolic murmurs:
a.MVP: Midsystolic click heard before late systolic murmur, heard best at fifth left ICS. Heard best with diaphragm; sitting or squatting may increase intensity.
b.Tricuspid valve prolapse: Heard over the left lower sternal border, delayed onset of murmur with inspiration secondary to an increase in the right ventricular volume.
I.Diastolic murmurs: Murmurs are always pathologic:
1.Early diastolic murmur:
a.Aortic regurgitation: High-pitch faint, decrescendo may start with S2 at third left ICS and radiates down sternal edge. Heard best leaning forward, holding breath. Increases with sudden squatting or handgrip. May hear displaced point maximal intensity, S3, bounding pulse.
b.Pulmonary regurgitation: Valvular, dilation of valve annulus, congenital defect (tetralogy of Fallot ventricular septal defect [VSD]), pulmonic stenosis. Best heard over left second/third ICS. May sound high pitched with blowing
sound in patients with hypertension (HTN). May be pansystolic, having decrescendo configuration.
2.Mid-diastolic murmur:
a.Mitral stenosis: Rumbling extends beyond mid-diastole at fifth ICS, heard best using the bell of the stethoscope. Increases with left lateral position. May hear snap after S2.
b.Tricuspid stenosis: Increased flow across the tricuspid valve, heard best at the left sternal border. Identified by its increase in intensity of the murmur with inspiration (Carvallo’s sign). Commonly seen with mitral stenosis.
Plan
A.General interventions:
1.Major therapeutic goals are to preserve quality of life, increase life expectancy and exercise capacity, and reduce risk of complications.
2.Activity restriction is not necessary in patients with asymptomatic valvular disease.
B.Patient teaching: Reassure the patient regarding specific diagnosis. Counsel the patient regarding his or her specific condition. Teach the patient signs and symptoms to report to the health provider, including chest pain, SOB, difficulty breathing, and so forth.
C.Medical and surgical management: Patients who need progressive increases in medications to control symptoms may be candidates for valve replacement surgery.
D.Pharmaceutical therapy:
1.The 2014 American College of Cardiology/American Heart Association (ACC/AHA) Guidelines do not recommend routine endocarditis antimicrobial prophylaxis treatment for common valvular lesions including a bicuspid aortic valve, acquired aortic or mitral valve disease (including MVP with regurgitation), and hypertrophic cardiomyopathy with latent or resting obstruction.
E.Endocarditis prophylaxis treatment: Cardiac conditions:
1.Prophylactic treatment is recommended for high-risk cardiac condition abnormalities. Specific cardiac conditions include the following:
a.Prosthetic cardiac valve or prosthetic material used for cardiac valve repair.
b.Previous infective endocarditis.
c.Certain congenital heart diseases, such as cyanotic congenital heart disease that has not been repaired; a congenital heart disease that has been repaired with an artificial material or device for 6 months after repair; and repaired congenital heart defects with continued problems such as leaks or insufficient flow at the prosthetic device or adjacent to the repair.
d.Postcardiac transplant valvulopathy.
2.Procedures for high-risk patients previously mentioned who require prophylaxis treatment:
a.All dental procedures with manipulation of gingival tissue or periapical region of teeth or perforation of oral mucosa.
b.Incision or biopsy of respiratory mucosa or any invasive procedure of the respiratory tract system.
c.Procedures that include infected skin or musculoskeletal tissue.
d.Preventative treatment with antibiotics is not recommended for procedures that include the reproductive tract, urinary tract, or gastrointestinal (GI) tract.
3.Antibiotic prophylactic regimens include single dose 30 to 60 minutes prior to procedure:
a.Amoxicillin 2 g by mouth, intramuscular (IM), or intravenous (IV) for adults.
b.Ampicillin 2 g IM or IV or 50 mg/kg IM or IV.
c.Allergy to PCN: Cephalexin 2 g by mouth for adults.
d.Azithromycin or clarithromycin 500 g for adults.
e.Allergic to these: Consider cefazolin or ceftriaxone 1 g IM or IV or clindamycin 600 mg IM or IV for adults.
4.Other pharmaceutical treatments depend on the specific valvular abnormality:
a.Mitral stenosis: The mitral valve has a narrowing that does not allow adequate blood to the left ventricle during diastole, usually due to rheumatic heart disease. Mitral heart disease is the most commonly seen valve effect with rheumatic heart disease.
b.Diuretics such as furosemide (Lasix) or hydrochlorothiazide (HydroDiuril) are used to control edema.
c.Digoxin (Lanoxin) or beta-blockers are used to control atrial fibrillation (AF) and irregular heart rate.
d.Warfarin (Coumadin) and the antiplatelet agent aspirin (Bayer) are used to prevent clotting.
e.MVP: The echocardiogram is the recommended test for diagnosis of MVP. Usually no medications are recommended except when symptomatic and required:
i.Beta-blockers (such as Atenolol) may be used for palpitations.
ii.Diuretics should be avoided in patients who are volume reserved.
iii.Oral contraceptives should be avoided in women who exhibit neurologic symptoms.
f.Mitral regurgitation: Diuretics, digitalis, and afterload-reducing agents for congestive heart failure (CHF):
i.Aortic stenosis.
ii.Diuretics are used for CHF.
iii.Avoid vasodilators; they may result in profound, irreversible hypotension.