Presentation made by Dr. Robin Pinto at the SIHD conference held in Mumbai.

1. INVESTIGATING STABLE IHD –
TREADMILL, DOBUTAMINE STRESS
ECHO OR STRESS THALLIUM??
Dr Robin Pinto
Holy Family Hospital,
Glenmark Cardiac Centre

2. FACTORS DECIDING CHOICE
• Ability to exercise
• Baseline ECG abnormalities
• Prior CABGS / PTCA / MI
• Portability
• Cost
• Radiation
• Physician Preference
• Sensitivity And Specificity

3. PROBABILITY OF CAD

4. VERIFICATION BIAS
• Describes the impact of reporting sensitivity
and specificity when calculated primarily using
patients with positive stress test results
• Sensitivity = TP / TP + FN
• Specificity = TN / TN + FP

5. VERIFICATION BIAS

6. ROLE OF ETT AS A DIAGNOSTIC TEST
TEST OF CHOICE IN THOSE WITH
WITH INTERMEDIATE TEST PROBABILITY
NORMAL BASLINE ECG
ABLE TO EXERCISE
NO PRIOR REVASCULARISATION

7. INCREASING SENSITIVITY OF ETT
EXISTING:
1. ST deviation and slope
2. ST / HR slope > 2.4 µV / bpm
3. ST / HR index > 1.6 µV / bpm
NEW:
1. ST / HR Hysteresis – integrates difference in
ST segment depression between exercise and
3 min of recovery .
2. Chronotropic incompetence

8. DST - ADVANTAGES
• Totally non invasive, safe , repeatable
• No radiation
• Relatively short procedure time
• Simple instrumentation, portable
• Can identify other structural abnormalities

9. Disadvantages of DST
• Images difficult to acquire because of marked
cardiac excursion
• RWMA may be transient
• Highly operator dependent
• Inability to image all segments in 15%
• Detection of residual ischemia in infarct zone
difficult

10. WHATS NEW IN DST
• Use of LV opacification
• MCI - microvascular perfusion, viability,
improving sensitivity of DST
• Use of Speckle tracking / Strain imaging

12. • 32 yr/ M,
• IGT,
• Non smoker,
• Atypical chest pain
• Intermediate pretest probability

15. 49 yr old marathon runner, CT Calcium Score = 1095.03

19. Microvascular re-perfusion Acute MI

21. No microvascular reflow

22. MPI – Myocardial Perfusion Imaging
• Can evaluate Ventricular function
• Most sensitive for diagnosis of CAD
• Identifies region of ischemia
• Can assess myocardial viability

24. DISADV OF MPI
• Attenuation artifacts
• In severe disease, balanced ischemia can lead
to a false negative test

25. PROGNOSTIC INDICATORS FROM ETT
• Duration of exercise < 6 METS
• Failure to increase syst BP > 120 mm Hg,
sustained decrease > 10 mm hg below rest
• ST depression > 2.0 mms
• Exercise induced ST elevation
• Angina at low workloads
• Sustained (> 30 secs) / symptomatic VT

27. NEWER PROGNOSTIC INDICATORS
FROM ETT
MORTALITY
• Functional Capacity (METS, DTS)
• Heart Rate Recovery - < 12 bpm in first min
• Chronotropic Incompetence < 80% THR
SUDDEN CARDIAC DEATH (SCD)
TWA (T-wave alternans) > 65 µV is high risk
Frequent PVCs in recovery > 7 / min

28. ADVERSE PROGNOSTIC MARKERS IN
DST & MPI
• Amt of myocardium - > 3 segments in DST, > 10%
myocardium in jeopardy
• More than one territory
• LV dysfunction – LV dilatation on DST, Fall in EF by
> 5%, Global EF < 45% , Transient ischemic
dilatation ratio > 1.2, Lung uptake, RV uptake /
dilatation

30. CONCLUSION
• Performing these tests routinely in the general
population is probably not indicated
• ETT – Test of choice for the majority of patients
with a baseline normal ECG and the ability to
walk on the treadmill
• DST / MPI – Those with a non diagnostic ETT and
intermediate test probability.

31. CONCLUSION
• DST – Increasing use, especially useful in those
with LBBB / bronchoconstriction
• MPI – especially to assess residual ischemia in
infarct territory, assess viability, post CABGS,
assess significance of non critical lesions
• Prognostic information gleaned from each of
these tests extremely important in making clinical
decisions