Echocardiography

Question 1

echocardiography

Answer 1

real time ultrasonographic imaging of the heart used to localize and diagnose cardiac disease

Question 2

what is echocardiogram able to do

Answer 2

1. diagnose ALL cardiac disease
2. estimates chamber size and wall thickness
3. estimates cardiac function
4. estimates hemodynamic data - CO, pressures
5. provides prognostic and treatment information
6. identifies RIGHT heart failure + PERICARDIAL disease

Question 3

can echocardiogram diagnose left heart failure

Answer 3

NO - requires thoracic radiographs

Question 4

can echocardiogram image the great vessels well

Answer 4

no

Question 5

what is the best positioning for an echocardiogram

Answer 5

lateral recumbency

R lateral –> view R side of the heart

L lateral –> view L side of the heart

Question 6

2D echocardiography

Answer 6

real time 2D cross sectional view of single or multiple parts of the heart in their anatomically correct position during multiple cardiac cycles

Question 7

does 2D echo provide information on blood flow velocity or direction

Answer 7

no - requires doppler

Question 8

what size should the LA be in comparison to the RA in a R parasternal long axis 4 chamber view

Answer 8

about equal

Question 9

what size should the LV be in comparison to the RV in a R parasternal long axis 4 chamber view

Answer 9

LV = 3 x RV

Question 10

M-mode

Answer 10

creates a time-motion graph by correlating change in structure with timing in the cardiac cycle (ECG)

Question 11

what is M-mode used for

Answer 11

evaluating IVS and LVFW thickness

calculating fractional shortening to estimate systolic function

Question 12

doppler echo

Answer 12

assesses blood flow at valves, defects +/- vessels

Question 13

functions of doppler echo

Answer 13

detects direction, velocity, character/quality, and timing of movement

can be used to calculate pressure gradients across valves, shunts, etc

Question 14

limitations of doppler echo

Answer 14

HIGHLY angle dependent

cursor alignment MUST be within 15-20 degrees of flow/movement

if at too much of an angle –> will underestimate velocity

Question 15

what kinds of doppler are there

Answer 15

color
spectral (pulsed wave, continuous wave)
tissue

Question 16

color flow doppler

Answer 16

applies color to shifts in frequency to rapidly detect abnormal flow

BART
- blue = away
- red = toward

Question 17

what is the velocity of laminar flow

Answer 17

appears as red and blue

100 cm/s (1 m/s)

Question 18

what is the velocity of abnormal flow

Answer 18

appears as rainbow flow (many different directions and velocities)

> 100 cm/s

Question 19

spectral doppler

Answer 19

uses a baseline to detect direction, velocity, and timing of blood flow

Question 20

function of spectral doppler

Answer 20

calculates pressure gradients

Question 21

direction on spectral doppler

Answer 21

+ is towards the probe
- is away from the probe

Question 22

velocity on spectral doppler

Answer 22

Y axis of the tracing in m/s or cm/s

Question 23

timing on spectral doppler

Answer 23

uses ECG to correlate blood flow changes to timing in the cardiac cycle

systolic –> just after QRS
diastolic –> during T to QRS

Question 24

how to calculate pressure gradient

Answer 24

Bernoulli’s equation
deltaP = 4 x velocity^2

Question 25

pulse wave spectral doppler

Answer 25

measures velocity and direction of flow at a specific point along the cursor allows for velocity assessment at a region of interest

Question 26

when to use pulse wave doppler

Answer 26

low (normal) velocity blood flow within the heart can only assess velocities <2 m/s - once over that, cannot determine direction

Question 27

continuous wave spectral doppler

Answer 27

measures velocity and direction of flow along entire cursor cannot localize the site of peak velocity

Question 28

when to use continuous wave doppler

Answer 28

high (abnormal) velocity blood flow within the heart can assess ANY velocity with accurate direction assessment

Question 29

LA:Ao ratio

Answer 29

used to measure L atrial size quantifies atrial enlargement INDEPENDENT of weight LA diameter / Ao diameter

Question 30

normal vs enlarged LA:Ao ratio

Answer 30

normal: LA:Ao < 1.6 enlarged: LA:Ao > 1.6

Question 31

fractional shortening

Answer 31

used to measure left ventricular function %FS = (LVIDd - LVIDs) / (LVIDd) x 100

Question 32

what is normal fractional shortening in dogs and cats

Answer 32

dogs: 30-40% cats: 40-60%

Question 33

what view is fractional shortening measured in

Answer 33

M-mode right parasternal short axis LV

Question 34

how to evaluate concentric and eccentric hypertrophy

Answer 34

ventricle diameter and wall thickness in 2D or M mode

Question 35

what is normal velocity across outflow tracts

Answer 35

<2 m/s

Question 36

inflow velocity

Answer 36

assesses AV valves during diastole E wave + A wave on spectral doppler

Question 37

E wave

Answer 37

early wave indicates early passive filling of ventricles

Question 38

A wave

Answer 38

late wave; indicates late active "atrial kick" filling of ventricles

Question 39

how to assess E and A wave

Answer 39

used to assess diastolic function E wave should be > A wave in normal animals due to majority of filling coming from passive flow down pressure gradient

Question 40

what does an E wave < A wave indicate

Answer 40

non compliant ventricles relying on atrial contraction to fill (ex. HCM)

Question 41

what is the normal velocity across semilunar valves

Answer 41

1 m/s

Question 42

what is a normal pressure gradient across semilunar valves

Answer 42

delta P = 4 x 1^2 = 4 mmHg

Question 43

if aortic pressure is 120 mmHg, how much pressure does the LV need to generate to eject blood into aorta

Answer 43

120 + 4 = 124 mmHg

Question 44

how do you use tricuspid regurgitation velocity (5 m/s) to estimate systolic pulmonary arterial pressure

Answer 44

calculate the pressure gradient across the regurgitant valve: - dP = 4 x 5^2 = 100 mmHg calculate the right ventricular systolic pressure if there is NO atrial enlargement (RASP = 5) : - RVSP = dP + RASP - RVSP = 100 + 5 = 105 mmHg if there is NO evidence of pulmonary stenosis on echo, then: - sPAP = RVSP - sPAP = 105 mmHg (normal sPAP = 25 mmHg) indicates severe pulmonary hypertension