Echo 3: Stress echo Flashcards

1
Q

What are 2 types of contrast echo?

A

-Bubble study
-Contrast echo

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2
Q

Indications for bubble study

A

-Detection of left to right shunt (patent foramen ovale)
-Pericardiocentesis in pericardial effusion

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3
Q

How does bubble study work?

A

-Agitated saline solution (air bubbles) injected IV
-SCV - RA - RV - Lungs
-Normal conditions - no bubbles seen in left heart
-Abnormal - Bubbles seen in left heart suggestive of left to right shunt
-Valsalva manoeuvre often required to unmask PFO

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4
Q

Indication for contrast echo

A

-LV opacification
-Improve visualisation of LV (LVSD, RWMA, LV thrombus) where image quality is poor

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5
Q

How does LV opacification work?

A

-Contrast agent: microbubbles 1-10um pass through pulmonary capillary bed -> pulmonary veins -> LA -> LV
-Consist of outer shell enclosing a gas
-US energy causes microbubbles to resonate, emitting more US signals

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6
Q

What does this image show?

A

LV opacification
2D vs Contrast

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7
Q

What does this image show?

A

Positive bubble study
Rest vs Valsalva

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8
Q

What are the 3 types of stress echo?

A

-Exercise - treadmill, bicycle
-Pharmacological - dobutamine (inotrope), dipyridamole (vasodilator)
-Pacing - poor SA node function that would be unaffected by either alternatives

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9
Q

Purpose of stress echo

A

-Allows comparison of resting and stress pictures to uncover potential hidden abnormalities at rest

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10
Q

Advantages and disadvantages of types of stress echo

A
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11
Q

Indications for stress echo

A

-IHD
-Valve pathology
-Other

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12
Q

Typical vs Atypical chest pain

A
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13
Q

Why not ETT for ischaemia?

A

-ECG changes and angina are picked up later in the duration of ischaemia
-Echo and MRI pick up earlier signs of ischaemia

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14
Q

2010 vs 2016 NICE guidelines chest pain

A

2010:
-Test depends on pre-test probability of having CAD

2016:
-First line investigation is CTCA
-If non-conclusive, functional imaging

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15
Q

What does this image show?

A

Myocardial perfusion scan at rest and stress

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16
Q

What does this image show?

A

CT coronary angiogram

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17
Q

Pros and Cons of CTCA

A

Pros:
-Available
-Quick
-Non-invasive
-Minimal risks

Cons:
-Radiation
-Claustrophobic
-Requires contrast
-Artefact (HR, breathing)

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18
Q

Pros and Cons of stress echo

A

Pros:
-Non-invasive
-No radiation
-Only 2 people to perform
-Minimal risks

Cons:
-Does not see coronaries
-Limitations of echo
-May require contrast
-Requires consultant interpretation/input

19
Q

Pros and Cons of coronary angiography

A

Pros:
-Direct visualisation of coronaries
-Simultaneous PCI
-Guides revasc decision (PCI vs CABG)

20
Q

Stress echo service requirements

A

-Echo machine (probe, ECG electrodes) with stress echo software
-Exercise equipment (treadmill), drug administration equipment (infusion pump, cannulas, contrast)
-Resuscitation and safety equipment (allergic reaction, arrhythmias, physical injuries)
-Trained and experienced staff (minimum 2)

21
Q

Patient preparation for stress echo

A

-Stop beta blocker
-Decision on stressor
-Baseline echo (screen for contraindications)
-Baseline ECG and BP
-Cannula (if required)
-Presence of PPM/ICD - settings check

22
Q

Contraindications for all forms of stress echo

A

-Recent ACS or MI
-Ongoing unstable angina
-Acute heart failure
-LV thrombus/other mass
-Recent ventricular arrhythmia
-Severe hypertension >220/110
-High grade AV block

23
Q

Contraindications for exercise stress echo

A

-Injury/disability
-Inappropriate footwear/clothing
-Inability to exercise efficiently
-Haemodynamically significant outflow tract obstruction (HOCM)

24
Q

Contraindications for dobutamine stress echo

A

-LVEF<35% - arrhythmogenic properties of Dobutamine
-Glaucoma - Atropine
-Severe prostate disease - Atropine
-Difficult cannulation
-Concomitant valve disease that needs assessing with stress (exercise)

25
Q

Stress echo methodology on treadmill

A

-Baseline imaging
-Bruce protocol exercise
-Peak imaging (within 90s)
-Recovery

26
Q

Stress echo methodology on treadmill

A

-Ramp protocol

26
Q

What is considered a maximal test in stress echo on treadmill

A

-9 minutes
-10 METS

27
Q

Dobutamine stress echo methodology

A

-5 micrograms given every 3 minutes
-Pictures taken every 3 minutes
-Repeated until 85% of MAX HR is reached or 40 micrograms

28
Q

Diagnostic end points for stress echo

A

-Workload at least 85% predicted for age and sex
-Marked ECG positivity
-Obvious echo positivity
-Severe chest pain

29
Q

Causes of test cessation in stress echo

A

-Intolerable symptoms
-Muscular exhaustion
-Severe hypertension (220/120)
-Symptomatic hypotension
-Arrhythmias

30
Q

Abnormal test in stress echo

A

-Symptoms: angina, presyncope, syncope, fatigue at low workload
-Ischaemia
-Arrhythmias
-PHT
-Ischaemia mitral regurgitation

31
Q

Which views are coronary territories visualised in during stress echo?

A

-Apical 4,3,2 chamber
-Parasternal long axis (PLAX)
-Parasternal short axis (PSAX)

32
Q

How are images displayed in stress echo?

A

-Clear, well optimised, on-axis views of the LV where all walls can be seen
-Stress echo software package allows direct comparison between images in a quad screen format

33
Q

What is hibernating myocardium?

A

-Body deliberately down-regulates contractility of segment
-To protect it from becoming ischaemic
-Looks hypokinetic at rest

34
Q

What is a viable response?

A

-RWMA at rest
-When oxygen supply is increased it is still alive and can be revascularised

35
Q

What is a viable/ischaemic (biphasic) response?

A

-Improves at low dose of dobutamine
-At higher doses segment becomes ischaemic and hypokinetic

36
Q

What is infarct/scarred tissue?

A

-No improvement in segment at any dose

37
Q

Features of normal stress echo peak pictures

A

-LV cavity size should reduce from baseline
-EF should increase from baseline
-All LV segments contract at same time

38
Q

Features of single/multi vessel disease stress echo peak pictures

A

Single vessel:
-New RWMA in coronary territory

Multi vessel:
-New RWMA in several territory
-Dilation of LV cavity size with reduction in EF

39
Q

Number of ischaemic segments in 17 segment model

A
40
Q

Other applications of stress echo?

A

-Asymptomatic severe aortic stenosis (exercise)
-Significant mitral valve disease (exercise)
-Cardiomyopathies (exercise)
-Low gradient aortic stenosis

41
Q

Purpose of low gradient/flow aortic stenosis DSE

A

-DSE corrects the flow by increasing contractility
-Increases flow across valve
-Determines whether issue is valve or ventricle

42
Q

Outcomes of of low dose DSE for low gradient aortic stenosis

A

True severe AS
-<0.2cm^2 increase in AV area
-Increase in mean gradient >40mmHg

Pseudo severe AS
>0.3cm^2 increase in AV area
-Minor changes in mean gradient
-Ventricular function was the limiting factor

Indeterminate
-Contractility/flow through valve does not improve
-Can’t tell whether AS or not