Murmurs in Valvular Diseases

Introduction

Murmer: vibrations produced by abrupt acceleration and deceleration of blood flow across valves

Laminar blood flow: parallel flow of blood such that there are no conflicting flows. Flow within the heart and great vessels

Turbulent flow: when the velocity of flow exceeds a critical level (beyond the Reynold’s #) flow becomes disturbed or turbulent which generates a sound

Frequency or pitch of noise is directly related to the velocity of the turbulent flow

Classification

Systolic

Ejection: flow through semilunar valve (aortic or pulmonic)

begins after S₁ and extends into S₂
diamond shape

Pansystolic (holosystolic): regurgitant flow through the mitral or tricuspid valve

begins after S1 and extends into S2

Diastolic

Inflow: related to turbulent flow across either AV valve
Regurgitant: caused by regurgitant flow from either great vessel into its respective ventricle

begins after S2

Aortic stenosis:

Etiology:

Deterioration of a congenitally bicuspid aortic valve
Senile calcific degeneration
95% have coexisting rheumatic mitral valve disease

Murmer: cresendo-decrescendo (diamond shape) – systolic murmer

Description: begins in systole after S₁

separated by short audible gap – represents period of isovolumetric contraction of left ventricle

crescendo – with ventricular contraction, ejection of blood through restricted orifice leads to a marked acceleration of flow Þ laminar flow disintegrates into turbulent jet into aorta

decrescendo – ventricle relaxes Þ forward flow decreases Þ murmer lessens in intensity

INTENSITY of murmer DOES NOT correlate well with severity of aortic stenosis

LENGTH of murmer DOES correlate with severity: more severe stenosis, longer it takes to force blood across the valve and the later the murmur peaks in systole

S₂ softens: leaflets become fixed in place

Quality: high frequency murmer (because of Ý pressure gradient)

heard in "aortic area"
radiates toward neck

Aortic Regurgitation (Aortic insufficiency)

Etiology:

Abnormalities of the valve leaflets:

Rheumatic
endocarditis
congenital (bicuspid valve)

Dilatation of aortic root:

Aortic aneurysm/dissection
Annulo-aortic ectasia
Marfan Syndrome
Syphilis

Murmer: Decrescendo Murmer – diastolic murmer

Description: regurgitation or leakage of blood into the left ventricle Þ reverse flow through the valve in diastole becomes very accelerated because of large pressure gradient between aorta and LV also because ventricular relaxation is quick

Begins at A₂ Þ decrescendo (max intensity at onset) Þ terminates prior to next S₁

Quality: high pitched purmer

heard at left sternal border with patient sitting, leaning forward and exhaling

Mitral Regurgitation (Mitral insufficiency)

Etiology:

structural abnormalities of the mitral annulus, valve leaflets, chordae tendinae, papillary muscles
myxomatous degeneration (mitral valve prolapse)
ischemic heart disease with papilary muscle dysfunction
infective endocarditis
idiopathic ruptured chordae
rheumatic deformity
hypertrophic cardiomyopathy
mitral annulus abnormalities (calcification of dilatation)
left ventricular enlargement

Murmer: pansystolic murmer (holosystolic) – systolic murmer

Description: blood leaks from high-presure ventricle into low-pressure atrium

uniform intensity throughout systole

begins with S₁: ventricular pressure exceeds atrial pressure Þ immediate retrograde flow across valve

continues through S₂: left ventricular pressure remains greater than that in the left atrium at time of aortic closure

no significant gap between S₁ and onset (same with Ventricular septal defect) – contrast to systolic ejection murmer

Quality: best heard at apex

high-pitched "blowing" quality
radiates toward left axilla
intensity does not change with inspiration

Mitral Stenosis

Etiology:

99.9% Rheumatic heart disease
Rare causes: congenital stenosis, calcification extending from mitral annulus, endocarditis
causes of diastolic murmers: hyperdymaic states (fever, hyperthyroidism, exercise)

Murmer: mid to late diastolic murmer with opening snap Þ decrescendo Þ crescendo

Description: begins after S₂ and is preceded by opening snap (opening of stenotic valves, before S₃; more severe stenosis produces shorter A₂–OS interval)

early diastole: murmur at its loudest because pressure gradient between atrium and ventricle is Max

decrescendo: transvalvular pressure gradient ß as ventricle relaxes

crescendo: atrial contraction

Severe stenosis: prolonged murmer (longer fade)

Quality: low pitch (pressure gradient between atrium and ventricle is low)

heard best at apex with patient in left lateral decubitus