ECG Stress Test, Cross Sectional Imaging

Question 1

Describe the ischemic cascade

Answer 1

Ischemia
Hypoxia => reduced ATP
Abnormal relaxation (ATP needed for actin myosin uncoupling)
Abnormal contraction
ECG changes
Angina => MI, arrythmia, HF

Question 2

Functional tests for CHD

Answer 2

ECG
Exercise ECG
SPECT, PET
Stress echo
Stress MRI
CT FFR
Invasive coronary physiology via catheters

Question 2

Functional tests for CHD

Answer 2

ECG
Exercise ECG

SPECT, PET

Stress echo
Stress MRI

CT FFR

Invasive coronary physiology via catheters

Question 3

Anatomical tests

Answer 3

CTCA

Invasive angiography - can insert stents and balloons at same time

Question 4

Ways of triggering stress clinically

-what can you assess

Answer 4

Physical exercise
-stress ECG
-SPECT
echo

Pharmacological

• dobutamine => inotropic stimulation to assess function and wall motion
• VD (adenosine) => assess perfusion

*avoid dobutamine if possible as patients often cannot increase their cardiac perfusion sufficiently

Question 5

Initial investigations

Diagnostic investigations of chest pain

Answer 5

Initial - ECG

• ST elevation/depression
• T inversion

Diagnostic - CTCA
-image the coronary vessels and heart structure

Question 6

Assessing for ischemic changes in the heart

-stress echocardiography

Answer 6

Stress echocardiography
-compare echo heart movement before and after dobutamine stress

Can assess for ischemia and its effects
RCA - septal mv
LAD - apex mv
LCx - ant lateral mv

Question 7

Assessing for ischemic changes in the heart

-SPECT/PET

Answer 7

Radioactive tracer injection

-can compare metabolic activity before and after exercise/pharmacological stress

Question 8

PET vs SPECT

-why is PET superior

Answer 8

Higher spatial and temporal image resolution
Higher contrast
Higher efficiency
-less radiation needed
-faster

Question 9

What is CMR