TV4101 - Diagnostic Tests in Cardiology

Thoracic radiographs can give an idea of cardiac size using the vertebral heart score

Can also have idea if LA is enlarged

Most important - only widelh avail modality that you have cardiogenic oedema which you generally need to have CHF

Always take an Orthogonal view?

Clock allwos us to see which chamber is enlarged

Measuring from carina down to apex of heart then a perpendicular line at widest point of heart

• Then measure each line to see how many vertebrae they cover starting from T4 and that is you VHS

VHS another disadvantage

• Diseases can cause enlarged hearts e.g. Hypertrophy or pericardial effusion

• As such VHS is more a cardiac silhouette if the pericardium is full of fluid VHS will be larger than normal but we can’t diff btw chambers with radiograph

Arrow - Pulmonary vein larger than Pulmonary artery

Left Atrial bulge

Both of these signs = Left atrial enlargement with congestive heart failure

Can also see dorsal elevation of trachea

VHS is 14

This is a globoid cardiac silhouette

DDX?

• Peric eff

• Dilated cardiomyopathy

• Severe valvular disease if you have severe remodelling

Echocardiography

Assess chambers - shape, thickness of wall

Fluid takes up no sound so is black

Bone is solid and bounces sound back so quite white

• Does make an acoustic shadow underneath it

Another acoustic barrier is lung surface - fluid air surface

• Seen as a bunch of lines going back and forth

• No tissue detail due to bouncing

Liver absorb some sound

Echo sees only muscle blood and fluid

Phased Array chad probe

• Small footprint - emits sound from 1-2 crystals so a small precise beam/point

• Can do both kinds of doppler

Doopler types

• Physics tool to measure blood flow

• Bottom left pic shows colour flow doppler

• Spectral doopler - diff way to plot flow (middle photo) - depicted as a graph

  • Anything floweing towards probe is a blood flow spike above baseline

  • Regurgitation is seen as little troughs

B mode / brightness mode

• See a 2d image

M mode

• 1 dimensional

Left pics

• Transverse plane

• Moving probe up higher towards aota and will be able to see more chambers (E)

• Ratio of LA to aorta to determine if its is enlarged

Left pic - Dog with DCM

• Enlarged chamber

• Valve is open so issue there

Top right

• Colour flow doppler see the triangle of regurgitation

Turbulent flow

• Vale insufficiency

• Valve stenosis

Radiograph limit - csn’t assess chamber size

Thoracic X-ray advantage - can detect oedema and potential dx chf

Trponin might have in horse with ionophore poisoning

Function marker

NT-proBNP = N terminal protein (hasn’t been coverted into active form yet) Brain naturalistic peptide

• Actually comes from LA wtf?

  • When LA is stretched

  • Released to offest toe actions of rrare? rest? system and sympath nervous system - but itsn’t strong enough to beat them so no therapetuic value

• It is a surrogate for neuro hormonal activaion in CHF (diagnostic value)

Also affected by Cushing’s

Or on fluids