Stress Echo

Question 1

Define ischemia

Answer 1

deficient supply of blood to a body part such as the heart of brain that is due to obstruction of the inflow of arterial blood

-patients can be assymptomatic

Question 2

What are some indications for a stress echo?

Answer 2

-coronary artery disease diagnosis
-prognosis and risk strat in patients with established diagnosis
-pre op strat
-evaluation of cardiac aetiology of external dyspnoea
-evaluation after cardiac revascularisation
-identify ischemia location
-evaluation of heart valve stenosis

Question 3

What are some absolute contraindications for stress echo?

Answer 3

-LV failure with symptoms at rest - low does dobutamine may be used to assess viability
-recent Hx of life-threatening arrythmia
-severe dynamic or fixed LVOT obstruction
-severe hypertension
-recent pulmonary emoblism, infarction and aortic dissection ( 48hrs)
-active endocarditic, myocarditis, pericarditis

Question 4

What are some relative contraindications for stress echo?

Answer 4

-LMS stenosis
-AV block
-Tachy/brady
-hypertension
-electrolyte abnormalities
-mental/physical disability

Question 5

What are some methods used for stress echo?

Answer 5

-pace to speed and slow down pacemaker
-supine bicycle
-pharmacological

Question 6

What are some advantages and disadvantages of using a supine bicycle for stress echo?

Answer 6

A- imaging during exercise, detection of diastolic dysfunction, better quality ECG/BP

D-low workload

Question 7

What are some advantages and disadvantages of using a dobutamine for stress echo?

Answer 7

A- imaging throughout diastolic and systolic, good quality ECG

D- side effects, non-physiological

Question 8

What are some advantages and disadvantages of using an upright bicycle for stress echo?

Answer 8

A- safety, better quality ECG/BP

D- technically difficult to image

Question 9

What are some advantages and disadvantages of using a treadmill for stress echo?

Answer 9

A- highly available, high workload, replicates daily activity

D- post stress imaging within 2 mins, ECG/BP

Question 10

What are some side effects of dobutamine?

Answer 10

-arrythmia, hypotension, angina, nausea

Question 10

What is dobutamine?

Answer 10

-short half life, acts on beta 1 receptors in cardiac muscle
-inotropic agent
-increases cardiac output, contractility, HR
-increased myocardial oxygen demand
-use with caution in AF

Question 11

What are some Echo modalities?

Answer 11

-2D
-m mode
-Colour flow mapping
-dopppler
-contrast
-strain rate

Question 12

How does the scoring system work for visualising myocardium?

Answer 12

1- normal ( myocardium contracts and relaxes as normal)
2- hypokinetic in response (thickening more than 50%)to dobutamine
3-akinetic (thinning of myocardium)
4-dyskinetic (myocardium is moving out of sync, goes in the opposite direction, 180 degrees out of synchronous, paradoxical systolic motion)
5-aneurysmal (loosing the blunt cone shape - diastolic deformation)

Question 13

How is contrast applied to a stress echo?

Answer 13

-delivered via IV
-aggitated saline, creates microbubbles and its injected, pacifies the LV to see walls and dysfunction

-improves endocardial border resolution/ definition
-image quality suboptimal for assessing regional and global function

Question 14

What is tissue doppler imaging?

Answer 14

-speckle strain imaging
-cursors over wall to look for the amount of displacement it is being moved via doppler ( is it moving towards the apex)
-REMEMBER doppler is always subject to angle >20 degress = underestimation
-post systolic shortening - detects movement post systolic, highlights this part of the heart did not contribute to the EF or FS

Question 15

What is a viability study?

Answer 15

-performed on patients with known CHD
-examines inotropic reserve of dysfunctional but viable myocardium ar rest by administeration of inotropic agent
-Supplying the myocardium - will it start to contract

Question 16

What gives a normal stress echo outcome?

Answer 16

rest- normokinesis
stress - normo to hyperkinesis

Question 17

What gives an ischemic diagnosis for stress echo?

Answer 17

rest- normokinesis
stress - hypokinesis, akinesis, dyskinesis

Question 18

What gives a viable diagnosis for stress echo?

Answer 18

rest - akinesis
stress- hypokinesis, normokinesis

Question 19

What gives a necrotic diagnosis for stress echo?

Answer 19

rest - akinesis to dyskinesis
sttress akinesis to dyskinesis

Question 20

What are the pre test instructions for stress echo?

Answer 20

-avoid heavy meal
-rate limiting drug stopped 48hrs before

Question 21

What equiptment is required for a stress echo?

Answer 21

-check resus equipt
-echo machine, treadmill/bike, syringe driver, syphgomomanometer

Question 22

What patient prep is required for stress echo?

Answer 22

-height/ weight
-explain test, gain consent
-symptoms
-medications
-physical acitivity
-decision on exercise or dobutamine
-12 lead ecg
-attach bp cuff
-Iv cannula
-position patient in left lateral semi supine position

Question 23

When should we terminate a stress echo test?

Answer 23

-ECG -ST changes, arrythmia, loss of signal
-BP drop of >20mmHg or uncontrolled hypertension >230mmHg
Symptoms/safety

Dobutamine:
-85% of HR achieved
-new or worsening wall motion abnomalities
-evidence of reduced global systolic function

Question 24

What needs to be done in stress echo recovery?

Answer 24

-Min 6 min recovery (longer if required) -possible side effects of dobutamine/ atropine may take longer -recovery images -discuss symptoms/ reason for stopping exercise -carefully review ECG

Question 25

What are some limitations of stress echo?

Answer 25

-technical quality of images ( body habitus/ COPD) -small window to obtain true peak images -operator dependant ( doppler angle dependant, skills to perform and interpret) -poor reproducibility -effort dependent -possible side effects of medications