An initiative in the evaluation of

Valvular Heart Disease

Echocardiography remains the most frequently used and usually the

initial imaging test to evaluate all cardiovascular diseases related to a

structural, functional, or hemodynamic abnormality of the heart or

great vessels.

Uses the ultrasound beams reflected by cardiovascular structures to

produce characteristic lines or shapes caused by normal or abnormal

cardiac anatomy.

Doppler and colorflow imaging provide reliable assessment of cardiac

hemodynamics and blood flow.

Single dimension

Graphically represents the motion of cardiac structures.

Used primarily to measure cardiac chamber size.

Timing of cardiac events.

Display subtle abnormalities of cardiac motion.

For determination of LV mass.

May overestimate the dimensions if the direction of ultrasound

beam is oblique to that structure.

Volumetric flow

Spatial pattern of flow

LV outflow

RV outflow

LV inflow

RV inflow

Left atrial filling (pulmonary vein flow)

Right atrial filling (SVC,IVC)

Descending aorta

Overall pattern of intracardiac flow is better demonstrated.

Angle dependent.

Physiologic valvular regurgitation.

Agitated saline

Specific contrast agents

For detection of intra cardiac shunts

For delineation of cardiac borders

For detection of PFO

In evaluation of valvular heart disease

During the past 20 years, echocardiography has gradually replaced

cardiac catheterization for most hemodynamic assessments in most

clinical practices.

Less than 5% pts undergo hemodynamic cardiac catheterization

before AVR for AS.

Less than 50% pts undergoing pericardiectomy.

Doppler hemodynamic assessment is sometimes more reliable,

accurate than invasive hemodynamic assessment, the best example

being Transmitral pressure gradient(PCWP used as LA pressure).

Peak(Maximal) instantaneous gradient is measured(Peak to

peak in invasive).

Mean gradient – average of pressure gradients during the entire

flow period.

Bernoulli principle.

Simplified Bernoulli equation.

P = 4V² or (2V) ²P =pressure difference

V = maximal velocity recorded across orifice by

CW doppler.

The simplified bernoulli equation ignores the proximal flow

velocity (v1) and estimates gradient based on the distal,or jet

velocity (v2),this is an acceptable simplification if v2 is

significantly greater than v1.

In case of proximal velocity (v1) is relatively high, this

simplification may be inappropriate.

If the gradient is low,the difference between v1 and v2 may be

relatively small and a more appropriate version of bernoulli

equation would be.

P = 4 (Vd² - Vp²)

Flow velocities recorded with doppler echocardiography are

used to determine various intracardiac pressures.

1.Pulmonary artery pressures Tricuspid regurgitation jet velocity gives the systolic pressure

difference between RV and RA.

TRJV = (RVSP - RAP)

RVSP = TRJV +RAP

RVSP = PASP in absence of any stenosis.

Pulmonary regurgitation velocity represents the diastolic pressure

difference between the pulmonary artery and PV.

PAEDP = RVEDP + 4(PREDV)²

PAEDP = RAP + 4(PREDV)²

PA Mean Pressure = 4(PR peak velocity)² .

PRJV

PREDV

AR velocity reflects the diastolic pressure difference between the

aorta and the left ventricle.

LVEDP = DBP – (AREDV)² 4

DBP = Diastolic Blood Pressure

EDV =End Diastolic Velocity.

According to the hydraulic orifice formula, flow (rate) across a

fixed orifice is equal to the product of the cross sectional area

(CSA) of the orifice and flow velocity:

Flow rate : CSA Flow velocity.

In hemodynamic calculations of flow, SV and orifice area by

doppler echocardiography.

TVI – flow velocity varies during ejection in a pulsatile

system,individual velocities of the doppler spectrum need to be

summed (i.e. integrated) to measure the total volume of flow

during a given ejection period.sum of velocities is called time

velocity integral.

SV = CSA TVI

Mostly LVOT is used to determine the stroke volume.

CSA of the orifices in the heart is usually assumed to be a circle, and

is determined by measuring the orfice diameter (D)

CSA = (D/2)²

CSA = D² 0.785

SV = D² 0.785 TVI

Cardiac output = SV HR

Cardiac index = CO /BSA

Based on conservation of mass.

A1 TVI1 =A2 TVI 2

Originally developed for evaluating patients with mitral

stenosis.

Time required for the peak pressure gradient to be reduced by

one half.

Time required for the peak velocity to decrease to a value

equal to peak velocity divided by 2.

Time required for the initial velocity to decrease to a value of

peak velocity divided by 1.4.

Peak velocity multiplied by 0.7

PHT increases with increase in stenosis.

Volumetric method:

RV = Aortic systolic flow – Mitral diastolic flow.

Regurgitant fraction (%) = Regurgitant volume / aortic outflow

volume *100%.

ROA = flow rate /Velocity

Novel application of continuity principle.

As blood converges toward an orifice,doppler flow imaging

reveals concentric shells or hemispheres which represent

isovelocity surfaces.

As the blood accelerates toward the orifice velocity alaising

occurs,distinct red blue interface occurs at the boundary of

shells.

Velocity is equal to nyquist limit.

Surface area =2r²

Flow rate = 6.28 r² aliasing velocity

Flow rate =ERO velocity jet

Index of LV contractility

Rate of LV pressure increase during early systole = dp/dt

Early mitral regurgitant velocity represents dp/dt as LA

Pressure varies little during isovolumic contraction.

Measuring the slope of the mitral regurgitation velocity.

Time interval between 1m/sec and 3m/sec

dp/dt = 32/time interval

Good correlation with cath data..

Normal dp/dt >1200mmhg /sec

Ratio of pressure to flow.

SVR = MR velocity /LVOT TVI

SVR = Mean aortic pressure – RA Pressure /CO (cath)

SVR > 0.27 has 70% sensitivity and 77% specificity for SVR

>14 WU.

PVR = TR velocity/RVOT TVI* 10+0.16

Workload on right ventricle

Derived by RHC – strong predictor of survival in patients with

pulmonary hypertension.

How much aggregate pulmonary artery will dilate with each

RV contraction.

PVCAP = SV/Pulse pressure of pulmonary artery

PVCAP = LVOT area* LVOT TVI / 4 (TR velocity² –PR

velocity ²)