DIASTOLIC MURMURS

Dr Prasanna VenkateshPG General Medicine

DIASTOLIC MURMURS always signifies structural heart disease, in contrast to some systolic murmurs

BASIC MECHANISMS

• Diastolic regurgitant murmurs are caused by retrograde flow across an incompetent semilunar valves

• Diastolic filling murmurs are caused by forward flow across the AV valve

Classification based on physiologic mechanism of production

Diastolic murmurs are subclassified according to time of onset & termination into

• Early diastolic murmur: confined to early diastole which begins with S2.

• Mid diastolic murmur: begins at a clear interval after S2 & ends before S1.

• Late diastolic murmur or presystolic murmur: occurs in presystole immediately before S1.

• Pan/holo diastolic murmur: begins with S2 occupy whole diastole & ends with S1.

• EDM & PDM are regurgitant murmurs due to retrograde flow across a incompetent semilunar valves

• MDM & LDM are filling murmurs due to obstruction to a forward flow across AV valves.

DIASTOLIC REGURGITANT MURMURS

EARLY DIASTOLIC MURMURS

• These are semilunar valve regurgitant murmurs which begin with S2

• High pitched- reflecting the high velocity of regurgitant blood flow from the great vessels.

• Shape(decrescendo) & length(short) of EDM reflects diastolic pressure gradient between aorta or pulmonary artery & respective ventricles

Causes of EDM

• Aortic Regurgitation

• Functional pulmonary regurgitation (Graham Steell murmur)

EDM IN ARMECHANISM

Isovolumetric relaxation of LV is very rapid, a large

gradient develops between aortic & LV

diastolic pressure

Murmur builds up to maximum intensity after

A2As diastole progresses,

gradient drops, murmur parallels the pressure drop in a decrescendo

fashion upto S1

PITCH & CHARACTER• Decrescendo, soft high pitched, blowing in character

• EDM of acute severe AR is medium-pitched as the velocity of the regurgitant flow is less rapid and relatively short as aortic diastolic pressure rapidly equalizes with the steeply rising diastolic pressure of unprepared and non-dilated LV.

• A “cooing dove” or musical diastolic murmur occurs due to the rupture or retroversion of an aortic cusp secondary to bacterial endocarditis or trauma & as a complication of syphilitic AR.

LOCATION

• In AR of valvular origin--EDM is best heard in sitting and leaning forward position during a held deep expiration along left sternal border in 3rd and 4th intercostal spaces (Neo aortic area)

• In aortic root etiology-- AR murmur is usually best heard at the right 2nd intercostal space and to the right of the sternum.

INTENSITY

• The degree of AR is directly proportional to the pressure head driving the flow in a retrograde fashion.

• Maneuvers that increase or decrease the diastolic aortic LV pressure gradient increase or decrease the intensity of the regurgitant murmur

INTENSITY

• Prompt squatting and isometric handgrip bring out the faint EDM,

• Amyl nitrate inhalation decreases its intensity.

• EDM of mild AR often disappears during later stages of pregnancy due to decreased peripheral vascular resistance

ASSOCIATIONS

• Pure AR without associated valvular stenosis can present with a prominent systolic ejection murmur as well as an Austin Flint rumble at the apex.

• The carotid pulse is rapid rising and has a large volume.

• In AR of valvular origin, A2 is often diminished or even absent-- due to an inadequate coaptation of the deformed cusps.

ABBREVIATED AR DIASTOLIC MURMUR

As the volume of blood in the aorta decreases during

diastole

The aortic annulus becomes smaller and coupled with

the decreasing aortic LV diastolic

gradient

Retrograde flow ceases, and the

murmur disappears

• The murmur of very mild AR can be abbreviated and can end by mid-diastole– functional AR murmur of systemic arterial hypertension

In acute AR

Acute regurgitation of blood into an LV

that has not adapted to a large-volume load results in marked elevation of the LVEDP with

equilibration of the aortic and LV

diastolic pressures.

As a result, retrograde flow ceases, and the

murmur disappears in the latter part of

diastole.

When AR is acute, there can be

preclosure of the MV, resulting in a

soft or absent S1 as well as absence of

the presystolic component of the

Austin Flint murmur

EDM in Functional PRGraham Steell murmur

EDM in functional pulmonary regurgitation

• The pulmonary annulus cannot with stand high pressures unlike aortic annulus and the murmur occurs in the setting of severe PAH when the pulmonary artery systolic pressure (PASP) is ≥ systemic pressure.

• The functional murmur of PR (Graham Steell murmur) is similar in both frequency and contour to that of AR because the hemodynamics responsible for their production are identical.

Functional PR Causes

• Valvular lesions: Severe MS or combined MS and MR with dominant MS, usually of rheumatic etiology. Rarely occurs in pure MR and almost never occurs with aortic valve disease.

• Primary pulmonary hypertension.

• Congenital heart disease with left-to right shunt and severe PAH

• Eisenmenger’s syndrome. Rarely, Graham Steell murmur may occur in cyanotic CHD with increased pulmonary blood flow and severe PAH as in TGA, DORV, single ventricle or TAPVC.

• Sometimes occurs in ASD without PAH due to the dilated pulmonary artery and increased pulmonary blood flow.

• Rarely audible in end stage renal failure secondary to fluid overload.

Characteristics

• High velocity regurgitant flow murmur• Short, high pitched• Blowing in character beginning with loud P2• Best heard at pulmonary area & often during

inspiration. Also can be heard at apex, if apex is formed by RV

• Most often it is helpful from the ‘company the murmur keeps’ --- loud P2, prominent a waves in JVP and left parasternal heave.

Pandiastolic or Holodiastolic Murmurs

• In severe AR and PR, the murmur becomes pandiastolic & the length of murmur reflects the duration of the pressure difference between aorta and LV in AR & PA and RV in PR, during diastole.

Diastolic murmur in organic PR

• The murmur of organic PR is quite different in quality and duration than either AR or the Graham Steell murmur.

• The murmur is delayed from P2 by a short interval and builds up quickly to a crescendo followed by a decrescendo that ends well before S1.

• In organic PR, the pulmonary artery pressure can be normal & the diastolic gradient between the PA and RV can be very small----- low-velocity retrograde flow and a lower-pitched murmur

• The murmur is heard only during the period of maximal gradient in early and mid diastole.

• This type of murmur can be congenital or acquired, as with pulmonic valve endocarditis, carcinoid syndrome, or surgical procedures on the pulmonic valve.

• It is often associated with a prominent systolic ejection murmur secondary to the large RV stroke volume

DIASTOLIC FILLING MURMURS

• Diastolic rumbles are caused by forward flow across the AV valves

Diastolic rumbles are delayed from their respective semilunar closure sound by isovolumetric relaxation period

Only after this period, when the atrial pressure exceeds the declining ventricular pressure--- AV valves open & filling

begins

There are two phases of rapid ventricular filling—early diastole & presystoleMurmurs

have tendency to

be more

prominent during

this period

• As the velocity of flow is relatively low, these murmurs have a low frequency content and are rumbling in character.

MID DIASTOLIC MURMUR

• MDM are diastolic filling murmurs that begin at a clear interval after S2 in rapid ventricular filling phase

• They are caused by the forward flow across the AV valves when the atrial pressure exceeds the declining ventricular pressure.

• They are low pitched and rumbling in character as the velocity of flow is relatively low

MDM in MITRAL STENOSIS

• MDM in mitral stenosis is a decrescendo diastolic filling rumble occurring in the first rapid filling phase

PITCH

• It is low pitched, rough and rumbling in character and sounds like a bullock cart slowly moving on a wooden bridge or the sound of a bowling ball racing down the alley.

• It is low pitched as the pressure gradient across the valve is low.

• In a calcified immobile valve, a higher frequency murmur with less intensity not accompanied by a thrill is often the auscultatory finding.

INTENSITY

• The intensity of the MDM correlates poorly with the severity of the obstruction, but the length of the murmur correlates well with the severity of the stenosis.

• The duration of the murmur is unreliable indicator of the severity in following conditions

• Low cardiac output states such as severe RVF, severe PAH where the murmur appears shorter due to lower LA pressure

• Associated hyperkinetic circulatory states such as anemia, pregnancy, thyrotoxicosis, anxiety where the murmur appears longer due to high cardiac output.

• Associated with conditions with high LVEDP such as aortic valve disease, CAD, systemic hypertension where the murmur becomes shorter due to obliteration of the trans-mitral gradient.

Association with arrhythmias: • In tachyarrhythmias--- the murmur appears longer due to

shortening of the diastole. Gentle carotid sinus massage may temporarily slow the heart rate, and thereby allow uncovering the potential length of the murmur.

• In bradycardia---the murmur appears shorter as diastole

is prolonged.

• In atrial fibrillation--- the duration of the murmur is variable as diastolic cycle lengths vary. If the murmur lasts upto S1 in longer cycles, it indicates the severity of the MS.

SITE

• The murmur is well localized and best heard just medial to the apex in left lateral position during expiration with the bell of the stethoscope.

• In patients with severe emphysema, the murmur is best heard only at the xiphisternum.

INTRODUCTION

• The murmur is often introduced by a prominent OS (in mobile valve) and is associated with a loud S1, presystolic accentuation and a diastolic thrill.

• In severe MS with severely calcified immobile valve, S1 is soft and no thrill is palpable.

• The A2–OS interval correlates with the level of LA pressure and thereby severity of the stenosis may be clinically determined to some extent.

DYNAMIC AUSCULTATION

• The bedside maneuvers such as left lateral position, hand grip exercise and amyl nitrate inhalation enhance the MDM of MS.

• Valsalva maneuver diminishes the murmur.