Heart Murmurs

Innocent Murmurs

Innocent murmurs have no associated structural problems or ECG/radiological findings.

timing - all innocent are systolic

less than or equal to 3/6

normal physiological split

no extra sounds

radiation to neck or back

they get better with a change in position - "if it goes away, so does the patient"

 

 

breath sounds vs murmur?

• ask them to exhale and hold

Innocent murmurs include:

• peripheral pulmonic stenosis (neonatal)
• Still's murmur
• venous hum
• pulmonary ejection
• supraclavicular bruit

Systolic

Systolic murmurs are graded out of 6, while diastolic murmurs are out of 4.

I: very faint

II: soft

III: moderate

IV: loud, with palpable thrill (ie, a tremor or vibration felt on palpation)

V: very loud, with thrill; may be heard when stethoscope is partly off the chest

VI: very loud, with thrill; may be heard with stethoscope entirely off the chest

 

Ejection Murmurs

diamond shaped - crescendo-decrescendo.

The later the peak in volume, the worse it is.

 

Innocent murmurs are by far the most common. These often disappear when the person sits upright.

 

aordic stenosis

• high frequency, reflexting the sizeable pressure gradient.
• best heard in aortic area at 2nd-3rd right intercostal space.
• typically radiates towards neck, but can often be heard across the chest
• can be harsh

 

pulmonary stenosis

 

 

atrial septal defects (ASD)

• due to increased flow across pulmonary valve
• best heard at upper-left sternal border

 

patent ductus arteriosus

 

 

Pansystolic Murmurs

Pansystolic, or holosystolic, murmurs, are caused by regurgitation of blood or through a ventricular septal defect. There is uniform sound intensity throughout systole.

There is no isovolemic contraction, as flow starts immediately.

 

mitral regurgitation

• continues after A₂
• usually flat, but can be crescendo
• best heard at apex, often radiating towarda left axilla
• high pitched and blowing quality

tricuspid regurgitation

• best heard along left lower sternal border

 

ventricular septal defect

• the smaller the hole, the louder it is
• best heard at 4th-6th left intercostal spaces
• harsh and high pitched
• may be associated with a palpable thrill
• can stop suddenly; as the muscle thickens

Diastolic

 

Early diastolic murmurs

Early murmurs result from regurgitant flow through either the aortic or pulomary valve

 

aordic regurgitation

• high pitched
• begins at A₂
• has decrescendo shape, with maximum intensity at onset
• best heard using diaphragm along left sternal border, with person sitting, leaning forward, and exhaling

 

pulmonary regurgitation

• lower pitched
• intensity may increase with inspiration (why?)

 

mitral or tricuspid stenosis

• preceded by opening snap
• loudest just after snap
• duration predicts severity
• low pitched; best heard with bell (mtral at apex, tricuspid near xyphoid)
• can have pre-systolic accentuation

hyperdynamic states such as fever, anemia, hyperthyroidism, and exercise can cause increased flow across normal mitral/tricuspid valves and cause a diastolic murmur.

Continuous Murmurs

Continuous murmurs are heard throughout the cardiac cycle and result from conditions where there is a persistent pressure gradient. It is defined as continuing through S2.

 

 

venous hums

• generally lower pitched and softer

 

patent ductus arteriosus

• combinations of stenosis and regurgitation can lead to a to and fro combined murmur

 

 

Patterns to Know

Fixed S2 Split: Atrial Septal Defect

weak/no femorals: coarctation

murmur quieter when sitting (vs lying down): likely normal (innocent)

• usually due toa decrease in venous return

down syndrome: atrioventricular canal defect

Turner syndrome: coarctation of aorta

DiGeorge Syndrome: Tetrology of Fallot