1. Treadmill testing (TMT) is used to detect myocardial ischemia by stressing the cardiovascular system during exercise and observing the physiological responses. 2. During TMT, increases in heart rate, blood pressure, cardiac output and oxygen consumption are measured along with ECG changes to detect ischemia. 3. Abnormal responses that may indicate ischemia include ST segment depression, elevated systolic blood pressure, chest pain, and failure to reach target heart rate.

1. TMT

2. • To detect presence of myocardial infarction
secondary to CAD
• To predict the prognosis

3. TMT
• Exercising muscles need energy to contract
and relax.
• Energy is derived from oxidative metabolism
to generate ATP.
• Energy requirement at rest or active state can
be estimated from measurement of
TOTAL BODY O2 UPTAKE = Vo2

4. TMT
• Fick equation demonstrates that
Vo2 = CO x Perip. O2 extractn (A-V o2difference)
• Vo2 expressed in multiples of resting o2
requirements ( Metabolic equivalents METs )
• 1 MET = basal resting energy expenditure
= 3.5mL o2 / kg body wt / mt

5. • Eg. 5 MET activity requires 5 times the energy
required at rest.
• Vo2 max = peak o2 uptake achieved during
highest level of exercise .
• Dep on age, sex, heridity, exercise habits, cvs
status

6. • During exercise,
• CO increases 4-6 times the resting levels
• HR- 2to 3 fold increase.
• SV plateaus at 50-60% of vo2 max
• O2 extraction at periphery can increase 3 fold
• Max A-V o2 difference has a physiologic limit
15-17mlo2 / 100ml blood

7. Vo2 Peak
• During tmt , pts are prompted to exercise not
until they reach vo2 max
• but rather to the vo2 that is attained during
symptom limited , maximum tolerated
exercise
• – this level is termed as vo2 peak

8. • Myocardial ischemia = demand supply mismatch
of o2 blood
• Many factors influence this delicate balance
• TMT is performed to stress these relationships
and observe the physiologic responses
• To assess the devolepment of ischemia
• And to evaluate at what level of myocardial o2
demand and physical activity ( work rate )
ischaemia occurs.

9. • Myocard o2 demand depends on
• 1.HR
• 2.BP
• 3.LV contractility
• 4.LV wall stress
( lv pressure/wallthickness/cavity size)

10. • Sympathetic activation
• Parasympathetic withdrawal
• Vasoconstriction, except in-
– Exercising muscles
– Cerebral circulation
– Coronary circulation
PHYSIOLOGY

12. Myocardial Oxygen Demand
• Indirectly measured as the Double Product or
rate pressure product
• “Double Product” = HR x SBP
• Reliable index of myocardial o2 demand
Increases to more than 20,000 on exercise

13. 1. Isometric (Static)
-weight-lifting
-pressure work for heart, limited
cardiac output
2. Isotonic (Dynamic)
-walking, running, swimming, cycling
-Flow work for heart
-↑CO,↓ TPR
3. Mixed

14. Isotonic exercise(cardiac output)
• Early phase- SV+HR
• Late phase-HR

15. Post Exercise
• Vagal reactivation
• ↑in well trained athletes
• Blunted in CCF

16. ENERGY REQ ACTIVITY
1 MET TAKING CARE OF SELF
WALKING INDOORS
WALK AT 2-3 mph
4 METS LIGHT WORK AROUND THE HOUSE
WALKING AT 3-4 mph
>4-<10 METS CLIMB 1 FLIGHT OF STAIRS/UP HILL
WALK>4 mph, SHORT RUNNING
SCRUBBING FLOOR,MOVING
FURNITURE
>10 METS RUNNING> 6-7 mph
HEAVY LABOUR
SWIMMING,FOOTBALL

18. Calculation of METs on the Treadmill
• METs = Speed x [0.1 + (Grade x 1.8)] +
3.5
3.5
• Calculated automatically by Device

20. Patient Assessment
• Withhold cardiac medications on the day of
study to better assess ischemic response
• If taking medications , to evaluate the effects
on HR, BP, Symptoms and ischemia during
exercise
• If ICD ; Peak HR < 10 beats/min below the
programmed heart rate threshold for
antitachycardia pacing & defibrillation

21. Contraindications to Exercise Testing
Absolute
• A/c MI (< 2 d)
• High-risk unstable angina
• Uncontrolled cardiac arrhythmias causing symptoms with
hemodynamic compromise
• Symptomatic severe AS
• Decompensated heart failure
• Acute pulmonary embolus or infarction
• A/c myocarditis or pericarditis
• Physical disability

22. Contraindications to Exercise Testing
Relative
• LMCA stenosis
• Mod- AS + symptoms
• CHB
• Tachyarrhythmias with FVR
• HOCM with sev. Resting gradient
• Mental or physical impairment leading to
inability to exercise adequately

23. • Rate of major complications (MI/ hospitaliation)
• <1-5 per 10,000 tests
• Recent MI, low EF, exertion induced myocard
ischemia & serious ventric. Arrythmias = Highest
risk
• Death < 0.5 per 10,000 tests

25. Pretest Probability
• Based on the pat's h/o ( age, gender, chest pain ),
phy ex and initial testing, and the clinician's
experience.
• Typical or definite angina →pretest probability
high

27. The Bruce protocol
• 1949 by Robert A. Bruce,
considered the “father of
exercise physiology”.
• Published as a standardized
protocol in 1963.
• gold-standard for detection
of myocardial ischemia when
risk stratification is
necessary.

32. Normal Response to Stress Testing
• Heart rate increases
• Blood pressure increases
• Cardiac output increases
• Total peripheral resistance decreases
• Dysrhythmias – isolated unifocal PVC’s and
PAC’s (suppressed at increased heart rate)
• Oxygen consumption increases

33. Exercise capacity
• Strong predictor of mortality & Non fatal
cardiovascular outcome in both men &
women with or without CAD
• Predicted METS = 18-(0.15x age)
• Predicted METS = 14.7- (0.13x age)

35. MHR
• HR max = 220 – age
• HR max = 208 – (0.7 x age)
• HR max = 206 – (0.88 x age)
• HR max = 164 – (0.7 x age)

36. Abnormal Response
to Stress Testing
• Heart rate fails to rise above 120 or unable to
attain THR of 85% of max
• SBP shows a drop
• Physically unable to complete test
• Marked hypertension, >260/115
• Chest Pain and/or unusual shortness of breath

37. Chronotropic incompetence
• inability of the heart to increase its rate to meet
the demand placed on it
• Independent predictor of mortality
• < 85 % of age predicted MHR = incomplete study
• Chronotopic index
[(HR max- HR rest )x 100 ]/[(220-age)- HR rest]
• < 80 % = CI
• <62 % = CI (B blocker)

38. HR recovery
• < 12beats / min after 1 min with post exercise
cool down
• < 18 beats / min after 1 min with complete
cessation of movement
• < 45 beats / min after 2 min.
• Associated with increase in mortality
indepently , in both asymptomatic and in ppl
with established heart disease

39. Exaggerated systolic pressure response
• > 210 mm hg ; > 190 mm hg
• Not an indication to terminate the test
• May indicate future development of
hypertension or adverse cardiac events

40. Excercise induced hypotension
• Systolic pressure during exercise < resting
pressure
• 20 mm hg fall in BP after an initial rise
• Reason to terminate the test
• More predictive of poor prognosis & multiple
vessel CAD
• Cardiomyopathy, LVOT obstruction,
hypovolumia, hypertensive medications

41. Low systolic peak
• Rise in BP to 140mm hg
• Overall rise less than 10 mm hg
– Severe CAD
– Worse cardiovascular outcome in persons with
and without CAD

42. Normal Response of ECG
to Stress Testing
• ECG Changes
– QRS complex ↓ in size
– PR,QRS,QT shorten
– J point ↓, resulting in up sloping of ST segment
– ST segment returns to baseline by 80
milliseconds
– PR segment may down slope(Inf leads– baseline
PQ junction)
– R amplitude may decr at rates > 130
– P ampl ↑
– T wave decreases

43. The Electrocardiographic Response

44. 1 = Iso-electric
2 = J point
3 = J + 80 msec
The Exercise ECG

45. • ST 60 -- HR > 130/min
• ST 80 -- HR ≤ 130/min

46. ST-Segment Changes on the Exercise ECG
ST DEPRESSION:
• Measurements made on 3 consecutive ECG complexes
• ST level is measured rel to the P-Q junction
• When J-point is depressed rel to P-Q junction at baseline:
– Net diff from the rest J junction - amount of deviation
• When the J-point is ↑ rel to P-Q junction at baseline and
becomes ↓ isoel with exercise:
– Mag of ST dep - P-Q junction and not the resting J point

47. Abnormal and Borderline ST-Segment Depression
• ABNORMAL:
– 1.0 mm or > horizontal or downsloping ST dep at
80 msec after J point on 3 consecutive ECG complexes
• BORDERLINE:
– 0.5 to 1.0 mm horizontal or downsloping ST dep at
80 msec after J point on 3 consecutive ECG complexes
– 1.5 mm or > upsloping ST dep at 80 msec after J
point on 3 consecutive ECG complexes

48. ECG changes during stress test

49. Normal
Rapid Upsloping
Minor ST
Depression
Slow Upsloping

50. Horizontal
Downsloping
Elevation (non Q
lead)
Elevation (Q wave
lead)

51. ECG Patterns Indicative of Myocardial Ischaemia
ECG Patterns Not Indicative of Myocardial Ischaemia

52. • In lead V4 , the
exercise ECG result is
abnormal early in the
test, reaching 0.3 mV
(3 mm) of horizontal
ST segment
depression at the end
of exercise.
• severe ischemic
response.

53. •The J point at peak exertion is
depressed 2.5 mm, the ST
segment slope is 1.5 mV/sec,
and the ST segment level at 80
msec after the J point is
depressed 1.6 mm.
• “slow upsloping” ST segment
at peak exercise indicates an
ischemic pattern in patients
with a high coronary disease
prevalence pretest.
•typical ischemic pattern is
seen at 3 minutes of the
recovery phase when the ST
segment is horizontal and 5
minutes after exertion when
the ST segment is
downsloping.

54. • abnormal at 9:30 minutes
ES test and resolves in the
immediate recovery phase.
•pattern in which the ST
segment becomes
abnormal only at high
exercise workloads and
returns to baseline in the
immediate recovery phase
may indicate a false-positive
result in an asymptomatic
individual without
atherosclerotic risk factors.

55. LEAD aVR
• 1mm or greater ST elevation – significant
predictor of LMCA, Proximal LAD or
multivessel CAD
• As an isolated marker, high sensitivity,
moderate specificity & high –ve predictive
value

56. CHANGES IN QRS
• Exercise induced BBB are rare < 0.5% or less
• If EI LBBB occurs @ HR > 125, CAD is unlikely
• IF EI LBBB occurs @ lower heart rates => death
& major cardiac events
• EI RBBB no risk

57. DUKES tread mill score
• Score = exercise time – (5xst deviation )- (4x
angina index)
– Angina score index:
• 1- non limiting angina
• 2- exercise limiting angina
• High risk : -11
• Intermediate risk +4 - -10
• Low risk > +5