RV (Dys)function – assessment

by echocardiography

Trevor Richens

Glasgow Sick Kids

The Forgotten Ventricle

Importance of RV Function

• Congenital Heart Disease

– Single “RV morphology” ventricles

– Systemic RV’s – Senning/Mustard/cTGA

– Post Op ToF

• Acquired Heart Disease

– Ischaemic Heart Disease

– Ventricular Failure

– Pulmonary Hypertension

– Post Heart Transplant

RV dysfunction

now known to

correlate with poor

outcome

Single Ventricle

Senning

Tetralogy

RV Structure

RV

MPA

RA

SVC

IVC

RPA

LPA

RVOT

Pulmonary Valve

Infundibulum

• RV “wraps

around” LV

RV Echo Lx

RV Sx

RV echo – Standard Views II

And in infants

Problems with RV Echo

• Poor windows – unless you’re <5Kg

– Particularly difficult to see anterior wall

• Difficult to delineate RV cavity

– Coarse trabeculations complicate edge detection

• Complex shape prevents “simple” mathematical models

• Pattern of contraction

– “Wringing” rather than contracting

Where and What to Measure

That said……

• MRI – seen as gold standard limited by:– Accessibility

– Cost

– Time (anaesthetic)

• Gated radionuclide techniques– Accessibility

– Cost

– Radiation exposure

• Invasive techniques – Contrast ventriculography, conductance catheters– Accessibility

– Cost

– Radiation exposure

Echo

• Cheap

• Quick (at bed-side)

• Accessible

• Non-invasive

• No radiation exposure

Right Ventricular Function

• 2D

• Tissue Doppler

– Spectral (systolic)

– Colour coded (mean)

• Deformation

– Strain

– Strain rate

Eyeball Assessment

• Using MRI as gold standard

• 22 patients – 16.6 +/- 7.1 years

• Eyeball vs. MRI

• Poor ability to assess either RV size or function by eyeballing

• Fine– But: Any method assessing changes in volume is

dependent on pre/after load so MRI flawed as well

Still, lots of information there

M Mode

Flat or Paradoxical Septum

Paradoxical Septal Motion

• RV volume Overload– ASD

– Severe TR

– Severe PR (e.g. post op Tetralogy)

– Partial anomalous pulmonary venous drainage (PAPVD)

• Post cardiac surgery to ventricular septum

• Pericardial effusion

• ?RBBB

Compare to LV

Severe Branch Pulmonary Stenosis

Compare to LV

2D Assessment

• Gross changes can be appreciated

• Quantitative, comparative measurements

are not possible

• Abnormal septal motion can indicate

potential pathology

2D Quantitative Assessment

• Complex shape prevents simple

mathematical mode

• No easy and reproducible way to measure

RV function

TAPSE• Tricuspid Annular Systolic Excursion

• Measure of RV function

• Correlates with other echo markers of RV function

• Predicts survival in PAH

>18mm

3D

• Theoretically solves the mathematical

modelling problem

• As yet unproven

• Echo windows still an issue – anterior RV

wall

• Demarcation of RV cavity still problematic

Correlation of 3D RV volume echo

Measurements • New Phillips 3D software

system

• Correlated with MRI

• Good results for – RV ejection fraction

– RV volumes

Journal of the American College of Cardiology

Volume 50, Issue 17, 23 October 2007, Pages 1668-1676

3D plus Contrast

• Eliminates:

– RV modelling issue

– Edge detection

• Still has problem of echo windows

• Remains a volumetric method therefore

dependent on preload and afterload.

Diastolic Function

• More difficult to assess than LV

• Preloading varies widely

• E/A ratio not a particularly good indicator

of RV diastolic function

Restrictive RV Physiology

• Post Op

Tetralogy of

Fallot

• Restrictive

Cardiomyopathy

Anterograde diastolic flow with atrial systole (A wave)

Right Ventricular Echo

• 2D

• Tissue Doppler

–Spectral (systolic)

–Colour coded (mean)

• Deformation

– Strain

– Strain rate

Tissue Doppler Imaging

• Well established for LV function

• Now sufficient data to justify use in

assessment of RV function

• Good review of the state of play– Gondi and Dokainish; Echocardiography 2007 24 522-532

RV Spectral TDi - How

• Apical 4 chamber view

• 3 – 5mm Doppler sample volume

• Position 10mm or so away from the TV

annulus

– Avoids sampling from cavity or RA due to

normal movement in cardiac cycle.

• Check Sampling plane is parallel to RV

free wall

Sa

Ea Aa

IVRT IVCT

ET

Spectral TDi

Colour Derived TDi

IVC

Sa

Ea

Aa

Movement artefact associated with respiration

RV TDi

• Profile is similar to

that seen in LV

• Normal values differ

• RV peak Spectral

velocity’s

Adult Child

Sa 15.2 10

Ea 15.7 13

Aa 15.2 8.7

RV Sa in Adult

Practice

• Decreased Sa velocity (<10cm/sec)

• In LVF– Reduction correlates

with high PAp / Lap

– Independent predictor of poor outcome in CHF

• In Inferior MI– Predicts RV infarction

by angiographic/ECG criteria

– Predicts cardiac death or rehospitalisation

• In pulmonary hypertension– Sa Reduced but not

shown to be predictive

Ea and Aa

• Less known

• Aa/Ea ratio correlates with RV end

diastolic pressure in some pathologies

• Ea reduced in RV pressure loading –

pulmonary hypertension

Myocardial Performance index

• Marker of Ventricular Dysfunction

• Covers systolic and diastolic dysfunction

• Adds components of systolic and diastolic function

– Isovolemic contraction time (time taken for RV pressure to rise and open pulmonary valve)

– Isovolemic relaxation time (time taken for RV pressure to fall and allow tricuspid valve to open)

• Expressed as a fraction of ejection time

Calculation of MPI• Use CW Doppler (two different cardiac cycles)

(Tei index)

TRPA

MPI = TR - PA

PA

Calculation of MPI

• Use TDi (Same cardiac cycle)

• By TDi appears to correlate better with clinical

parameters

Sa

Ea Aa

IVRT IVCT

ETMPI = IVRT + IVCT

ET

RV MPI

Other Indices

• Acceleration during isovolumic contraction– Reduction correlates

with poor RV function (<2.5m/sec2)

– Relatively unaffected by preload and afterload

• Can be hard to image

• Looked good in animals but not so sure in humans

Assessment of timing

Off Line TDi

Effect of biventricular pacing

Right Ventricular Echo

• 2D

• Tissue Doppler

– Spectral (systolic)

– Colour coded (mean)

• Deformation

–Strain

–Strain rate

Strain and Strain Rate

• All previous measures of RV function are preload and afterload dependent

– Filling state

– LV function

– Hypertension

• Strain measures local ventricular wall deformation

– Largely independent of loading

Calculation of SR

• Measures the deformation of a small area of myocardium

• Use TDi to determine the velocities at two different points

• Divide the difference by the distance between them

Problems

• In LV fibre orientation is longitudinal or radial

• In RV fibres are oblique and contraction “wringing”

– Unclear as yet how this effects the measurements

• Normal values for RV have not yet been validated

Conclusion

• Useful information can be gleaned from eyeball

assessment

• Quantitative, comparative data needs careful

assessment by:

– TAPSE

– MPI

– TDi Sa

• Load independent assessment may be possible

with strain rate technology

» MRI might be better at the moment