Cardiology: Ischemic Heart Disease & Stress Testing

Question 1

1. What is the Glagov phenomenon?

Accepted Answer

Positive (outward) arterial remodeling: as plaque grows, the vessel wall expands outward so the lumen stays roughly the same size until plaque occupies about 40% of the vessel area.

ELI5: The pipe bulges outward to make room for the gunk, so the opening looks normal for a long time even though the wall is getting sick.

Question 2

2. In Gould's classic 1974 flow curve, at roughly what diameter stenosis does maximal (hyperemic) coronary flow begin to fall?

Accepted Answer

Around 50% diameter stenosis; maximal flow reserve falls progressively beyond that and steeply beyond about 70–80%.

ELI5: Once half the pipe is blocked, it can no longer push extra water when you open the tap all the way.

Question 3

3. In Gould's curve, at roughly what stenosis does resting coronary flow fall?

Accepted Answer

Not until about 85–90% diameter stenosis, because distal arterioles dilate at rest to compensate.

ELI5: At rest the heart sips so little that even a badly narrowed pipe can keep up, until it is almost closed.

Question 4

4. What is the order of the ischemic cascade from earliest to latest?

Accepted Answer

Flow maldistribution/perfusion heterogeneity, then reduced perfusion, diastolic dysfunction, systolic (wall-motion) dysfunction, ECG changes, and finally angina.

ELI5: The blood shortage shows up on the plumbing map first, then the muscle stiffens, then it squeezes weakly, then the wires show it, and pain comes last.

Question 5

5. Where on the ischemic cascade do nuclear MPI and vasodilator CMR detect disease?

Accepted Answer

At the earliest step, perfusion heterogeneity, which is why perfusion imaging is more sensitive than wall-motion imaging or ECG.

ELI5: Perfusion imaging catches the problem at the first domino.

Question 6

6. Where on the ischemic cascade does stress echo or dobutamine CMR detect disease?

Accepted Answer

At systolic dysfunction (new wall-motion abnormality), a later step than perfusion.

ELI5: Echo waits until the muscle is actually squeezing badly.

Question 7

7. Where on the ischemic cascade does the stress ECG detect disease?

Accepted Answer

At the ECG-change step, late in the cascade, which explains its lower sensitivity.

ELI5: The ECG only notices once the problem is well underway.

Question 8

8. When can a stress ECG alone (no imaging) be considered?

Accepted Answer

In a patient who can exercise and has an interpretable resting ECG; the 2021 ACC/AHA chest pain guideline gives this a Class 2a recommendation.

ELI5: If the heart's electrical baseline is clean and they can walk, the plain treadmill test is often enough.

Question 9

9. List the classic absolute contraindications to exercise stress testing.

Accepted Answer

Acute MI within 2 days, high-risk unstable angina, uncontrolled arrhythmias causing symptoms or hemodynamic compromise, symptomatic severe AS, uncontrolled symptomatic HF, acute PE or pulmonary infarction, acute myocarditis or pericarditis, and acute aortic dissection.

ELI5: Don't push someone to run if their heart or big blood vessels are actively in crisis.

Question 10

10. Which four absolute contraindications to exercise testing are new in the ASNC 2026 stress guideline?

Accepted Answer

Acute LV thrombus, symptomatic or severely enlarged aortic aneurysm, acute DVT, and significant anemia or ongoing blood loss.

ELI5: New list adds a loose clot in the heart, a bulging aorta, a fresh leg clot, and running low on blood.

Question 11

11. List the relative contraindications to exercise testing.

Accepted Answer

Left main stenosis, moderate stenotic valve disease, electrolyte abnormalities, severe arterial hypertension, tachy- or bradyarrhythmias, HCM or other outflow obstruction, mental or physical impairment preventing adequate exercise, and high-degree AV block.

ELI5: Things that make exercise riskier but can be worked around with care.

Question 12

12. What is the most common relative contraindication to exercise testing that needs to be addressed, and what is the threshold?

Accepted Answer

Severe hypertension, resting BP >200/110 mmHg.

ELI5: Blood pressure already sky-high before you start is the usual thing to fix first.

Question 13

13. Formula for positive likelihood ratio?

Accepted Answer

Sensitivity / (1 − specificity).

ELI5: How much a positive result multiplies the odds of disease.

Question 14

14. Formula for negative likelihood ratio?

Accepted Answer

(1 − sensitivity) / specificity.

ELI5: How much a negative result shrinks the odds of disease.

Question 15

15. Which test metrics depend on disease prevalence, and which do not?

Accepted Answer

PPV and NPV depend on prevalence; sensitivity, specificity, and likelihood ratios are intrinsic to the test.

ELI5: Whether a positive result is trustworthy depends on how common the disease is in the people you test.

Question 16

16. In which pre-test probability group does stress testing change post-test probability the most?

Accepted Answer

Intermediate pre-test probability; at very low or very high pre-test probability, results rarely change management.

ELI5: Tests help most when you genuinely don't know the answer yet.

Question 17

17. Which resting ECG findings make the exercise ECG uninterpretable so that imaging is required?

Accepted Answer

Pre-excitation (WPW), >1 mm resting ST depression, complete LBBB, and ventricular paced rhythm.

ELI5: If the ECG baseline is already scrambled, you can't read stress changes on top of it.

Question 18

18. Does RBBB reduce the diagnostic accuracy of the exercise ECG?

Accepted Answer

No; RBBB has no effect on overall diagnostic accuracy (ST depression in V1–V3 is ignored, but lateral and inferior leads remain interpretable).

ELI5: A right bundle block mostly messes up the right-sided leads, and the rest still work.

Question 19

19. Besides the four on the slide, which other baseline factors reduce exercise ECG specificity?

Accepted Answer

Digoxin and LVH with repolarization abnormality.

ELI5: Some drugs and thick heart muscle make the ST segments droop even without blockages.

Question 20

20. List the absolute indications to stop an exercise test.

Accepted Answer

SBP drop >10 mmHg with other evidence of ischemia, moderate-to-severe angina, sustained VT, ST elevation ≥1 mm in a lead without diagnostic Q waves, cyanosis/pallor/ataxia/near-syncope, and technical difficulty monitoring.

ELI5: Stop now if pressure crashes with ischemia, pain gets bad, a dangerous rhythm appears, or you can't see what's happening.

Question 21

21. List the relative indications to stop an exercise test.

Accepted Answer

SBP drop >10 mmHg without other ischemia, >2 mm horizontal or downsloping ST depression, hypertensive response >250/115, other arrhythmias (NSVT, SVT, heart block), fatigue/SOB/claudication/cramps, increasing chest pain, and BBB or IVCD indistinguishable from VT.

ELI5: Warning signs that usually mean stop, but a judgment call.

Question 22

22. A BP drop >10 mmHg during exercise is absolute or relative indication to stop?

Accepted Answer

Absolute if accompanied by other evidence of ischemia; relative if isolated.

ELI5: A falling pressure is scarier when other ischemia signs are also present.

Question 23

23. What were the complication rates in the 1980 Stuart analysis of ~500,000 stress tests?

Accepted Answer

Per 10,000 tests: 3.5 MIs, 4.8 serious arrhythmias, and 0.5 deaths, totaling about 9 per 10,000 (<1 per 1,000).

ELI5: Out of ten thousand treadmill tests, about nine have a serious problem and about one death occurs every twenty thousand.

Question 24

24. Which stress modalities are contraindicated with a severe aortic aneurysm?

Accepted Answer

Exercise and dobutamine (they raise shear stress and BP); risk is low with aneurysm <5.5 cm.

ELI5: Don't spike blood pressure in someone with a big bulging aorta.

Question 25

25. In aortic stenosis, when are all forms of stress contraindicated?

Accepted Answer

Symptomatic severe AS.

ELI5: If the narrow valve already causes symptoms, don't stress the heart.

Question 26

26. What are the stop criteria for exercise in asymptomatic AS per the lecture?

Accepted Answer

85% MAPHR, symptoms, a 20 mmHg BP drop, or >2 mm ST depression.

ELI5: Use a lower ceiling and stop at the first sign of trouble.

Question 27

27. How long after cocaine use should stress testing wait?

Accepted Answer

At least 12 hours.

ELI5: Let the cocaine clear before adding more stress to the heart.

Question 28

28. How should CKD/ESRD patients be approached for vasodilator stress?

Accepted Answer

Green light to test, with a low threshold to use aminophylline for side effects.

ELI5: Kidney patients can be tested; just be ready with the antidote.

Question 29

29. What potassium range should stress testing be avoided outside of?

Accepted Answer

Avoid testing with K <3.0 or >5.5 mmol/L.

ELI5: If potassium is too low or too high, the heart's rhythm is fragile.

Question 30

30. Dose of aminophylline to reverse vasodilator stress?

Accepted Answer

50–125 mg slow IV push over 30–60 seconds, repeatable to a maximum of 250 mg.

ELI5: A modest dose given slowly, and you can top it up a bit.

Question 31

31. Order of preference of vasodilator agents to minimize respiratory risk?

Accepted Answer

Regadenoson >> adenosine >> dipyridamole.

ELI5: Regadenoson is the gentlest on the lungs.

Question 32

32. By how much do vasodilators increase myocardial blood flow compared with exercise?

Accepted Answer

Vasodilators increase MBF about 3.5–4-fold; exercise typically produces roughly 2–3-fold.

ELI5: Drugs can open the pipes wider than running does.

Question 33

33. What exercise goals allow maximal metabolic demand per the lecture?

Accepted Answer

At least 6 minutes of exercise and ≥85% of MAPHR.

ELI5: Six minutes and 85% of max heart rate means you really pushed the heart.

Question 34

34. Approximate METs at the end of Bruce stages 1 through 4 per the lecture?

Accepted Answer

4.5, 7, 10, and 13 METs (estimated VO2 17, 25, 35, 47 mL/kg/min).

ELI5: Each stage adds roughly three METs.

Question 35

35. How many mL/kg/min of oxygen is 1 MET?

Accepted Answer

3.5 mL/kg/min.

ELI5: One MET is how much oxygen you burn sitting still.

Question 36

36. When can a submaximal post-MI exercise test be performed per the lecture?

Accepted Answer

3–5 days post-MI.

ELI5: A light test within the first week.

Question 37

37. What are the endpoints of a submaximal post-MI test?

Accepted Answer

5 METs, 70% MAPHR, HR 120–130, mild angina, ≥2 mm ST depression, exertional hypotension, or ≥3 consecutive PVCs.

ELI5: Stop at a modest workload or the first warning sign.

Question 38

38. What defines a positive exercise ECG?

Accepted Answer

≥1 mm horizontal or downsloping ST depression 80 ms after the J point, ≥1 mm ST elevation in a lead without a baseline Q wave, or ventricular tachycardia.

ELI5: A flat or down-sloping dip, a rise where there's no old scar, or a dangerous fast rhythm.

Question 39

39. Which ST depression morphology is least specific for ischemia?

Accepted Answer

Upsloping ST depression.

ELI5: An upward-sloping dip is often normal with fast heart rates.

Question 40

40. What does ST elevation in a lead without Q waves during exercise mean?

Accepted Answer

Transmural ischemia, which localizes the culprit territory; it is an absolute stop criterion.

ELI5: Elevation over healthy muscle means a severe blockage right there.

Question 41

41. Does exercise ST depression localize the ischemic territory?

Accepted Answer

No; ST depression does not localize ischemia, whereas ST elevation does.

ELI5: Dips tell you there's a problem but not where.

Question 42

42. What does ST elevation in aVR during exercise suggest?

Accepted Answer

Left main or proximal LAD disease (high-risk anatomy).

ELI5: A rise in that odd lead points to the biggest artery being in trouble.

Question 43

43. What is the single most powerful prognostic marker during exercise testing, including MPI variables?

Accepted Answer

Exercise capacity (workload/METs achieved).

ELI5: How far you can go on the treadmill predicts survival better than anything else.

Question 44

44. What survival benefit per MET was reported by Myers 2002?

Accepted Answer

About 12% improvement in survival per 1-MET increase in exercise capacity.

ELI5: Every extra stage-unit of fitness buys about 12% better survival.

Question 45

45. In Bourque JACC 2009, what was the prevalence of significant LV ischemia (≥10%) in patients achieving ≥10 METs?

Accepted Answer

0.4%.

ELI5: If you can go 10 METs, you almost never have a big area of ischemia.

Question 46

46. In Bourque 2009, what was the prevalence of significant ischemia with <7 METs versus 7–9 METs?

Accepted Answer

7.1% with <7 METs and 4.3% with 7–9 METs (difference not significant), versus 0.4% at ≥10 METs.

ELI5: Lower fitness, more chance of real ischemia.

Question 47

47. List the high-risk exercise stress variables.

Accepted Answer

ST depression >2 mm, ST depression at low workload, ST depression lasting >5 min into recovery, ST elevation >1 mm, abnormal BP response, workload <5–7 METs, exercise-induced VT, and abnormal HR recovery.

ELI5: Deep, early, long-lasting ECG changes, poor fitness, falling pressure, or dangerous rhythms signal high risk.

Question 48

48. Formula for the Duke treadmill score?

Accepted Answer

Exercise time (min) − 5 × maximal ST deviation (mm) − 4 × angina index.

ELI5: Start with how long you walked, then subtract points for ECG changes and chest pain.

Question 49

49. What are the angina index values in the DTS?

Accepted Answer

0 = no angina, 1 = non-limiting angina, 2 = test-limiting angina.

ELI5: No pain, pain you walk through, or pain that stops you.

Question 50

50. What DTS defines low risk and its 1-year mortality?

Accepted Answer

DTS ≥ +5, with about 0.25% annual mortality.

ELI5: A high score means very low risk.

Question 51

51. What DTS defines intermediate risk and its 1-year mortality?

Accepted Answer

DTS +4 to −10, about 1.25% annual mortality.

ELI5: In the middle.

Question 52

52. What DTS defines high risk and its 1-year mortality?

Accepted Answer

DTS ≤ −11, about 5.25% annual mortality.

ELI5: A very negative score means high risk.

Question 53

53. Calculate the DTS: 9 minutes Bruce, 2 mm ST depression, non-limiting angina.

Accepted Answer

9 − 10 − 4 = −5, intermediate risk.

ELI5: Nine minus ten minus four equals minus five.

Question 54

54. What is the normal heart rate response to exercise?

Accepted Answer

About 10 bpm per MET.

ELI5: Each step up in effort raises the pulse by about ten.

Question 55

55. How is chronotropic incompetence defined?

Accepted Answer

Failure to achieve ≥85% MAPHR or a chronotropic index <0.80.

ELI5: The heart can't speed up enough.

Question 56

56. Formula for chronotropic index?

Accepted Answer

(Peak HR − resting HR) / (age-predicted max HR − resting HR).

ELI5: What fraction of the expected heart-rate rise you actually achieved.

Question 57

57. What chronotropic index cutoff is commonly used on beta-blockers?

Accepted Answer

<0.62.

ELI5: Beta-blockers hold the heart rate back, so the bar is lower.

Question 58

58. Gender-neutral maximum predicted heart rate equations?

Accepted Answer

220 − age (Karvonen 1957) and 208 − 0.7 × age (Tanaka 2001).

ELI5: The classic and the newer formula for top heart rate.

Question 59

59. Sex-specific MPHR equations from Calvert 1997?

Accepted Answer

Women: 192 − 0.7 × age; men: 201 − 0.6 × age.

ELI5: Separate formulas for women and men.

Question 60

60. Define a hypertensive response to exercise.

Accepted Answer

Peak SBP ≥210 mmHg in men or ≥190 mmHg in women.

ELI5: Pressure climbs too high, higher bar for men.

Question 61

61. Define a hypotensive response to exercise.

Accepted Answer

A ≥10 mmHg fall in SBP with peak exercise.

ELI5: The pressure drops when it should rise.

Question 62

62. Why is exercise-induced hypotension high risk?

Accepted Answer

It signals extensive ischemia (often left main or three-vessel disease) or severe LV dysfunction or outflow obstruction.

ELI5: The pump can't keep up under load.

Question 63

63. What is an abnormal heart rate recovery?

Accepted Answer

A reduction of ≤12 bpm at 1 minute (slide says <12 bpm) with an upright cool-down (Cole, NEJM 1999).

ELI5: If the pulse barely drops after a minute, that's bad.

Question 64

64. What does abnormal HR recovery predict?

Accepted Answer

Increased all-cause mortality (higher 6-year death risk in Cole), independent of perfusion and workload.

ELI5: A slow-to-recover heart rate predicts dying sooner.

Cardiology: Ischemic Heart Disease & Stress Testing

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