2. OUTLINE
• INTRODUCTION
• TYPES OF STRESS TESTING
• PHYSIOLOGY OF EXERCISE
• DEFINITION OF TERMS
• INDICATION FOR EXERCISE STRESS TEST
• PRETEST PROBABILITY
• CONTRAINDICATIONS TO EXERCISE STRESS TEST
• EXERCISE PROTOCOLS
• PRETEST PREPARATION
• TREADMILL PROTOCOLS
• RECOVERY AFTER EXERCISE
• TERMINATION OF STRESS TEST
• ECG CHANGES
3. INTRODUCTION
. Exercise stress test is a noninvasive tool to evaluate
the cardiovascular system response to exercise.
.Exercise is the body;s most common physiologic
stress,and it places major demand on the
cardiopulmonary system.
.Thus exercise can be considered as the most practical
test of cardiac perfusion and function.
.The body increases its resting metabolic rate up to
20times and cardiac output about 6times during
exercise.
4. TYPES OF STRESS TESTING.
• 1.Exercise.
• a Treadmill
• b Bicycle
• 2.Pharmacological
• a Adenosine
• b Dobutamine
• c Dipyridamole
• d Isoproterenol
3.Other
Pacing
5. PHYSIOLOGY OF EXERCISE
• Patient position-supine or upright
• At rest CO and SV more in supine position
than upright position.
• Change from supine to upright position during
exercise causes increase in CO due to increase
in HR and SV.
6. PHYSIOLOGY 0F EXERCISE
• There are various types of exercise
• A Isotonic or Dynamic exercise
• cycling
• swimming
• rock climbing
• B Isometric or static exercise
• holding a static push up position.
• holding a dumbell in one hand
• pushing against an immovable object.
• C Resistive Exercise-combined isotonic and isometric.
7. DEFINITION OF TERMS
• METABOLIC EQUIVALENT(MET)-Defined as the caloric
consumption of an active individual compared with
the resting basal metabolic rate.Used as an estimate
of functional capacity
• One MET is defined as 1kcl per kg per hour and is the
calorie consumption of a person while at complete
rest.
• Low METs during treadmill exercise stress test is
associated with a worse prognosis while higher METs
are associated with better outcomes.
10. MAXIMAL PREDICTED HEART RATE
• Maximal predicted heart rate=220-Age
• It is accepted that a heart rate of 85% of the
maximal predicted heart rate for the patient is
sufficient to elicit and ischaemic response,and
its considered an adequate heart rate for a
diagnostic exercise stress test(EST)
11. BORG SCALE
• Borg scale is a numeric scale of perceived
patient exertion commonly used during EST.
• Values of 7 to 9 represent light work and 13 to
17 hard work.A value above 18 is close to the
maximal exercise capacity
• The Borg scale is particularly useful when
evaluating functional capacity during EST
12. INDICATIONS FOR EXERCISE STRESS
TESTING
• Elicit abnormalities not present at rest.
• Likelihood of coronary artery disease
• Extent of coronary artery disease
• Estimate prognosis of CAD
• Estimate functional capacity
• Effect of treatment
• Exercise precription
13. METHODS OF DETECTING ISCHAEMIA
DURING STRESS TESTING
• Electrocardiography
• Echocardiography
• Myocardial perfusion imaging
• Positron emission tomography
• Magnetic resonance imaging
14. Pretest Probability
• Age
• Gender
• Angina
• H/o previous MI
• Q waves in ECG
• Resting ST-T
changes
• Diabetes
• Dyslipidemia
• Smoking
• Diagnostic Test utility
• Most in intermediate
probability
• Least in high or low
probability
• Typical Angina
• Sub-sternal location
• Provoked by exertion
or emotion
• Relieved by
rest/GTN
15. Pre Test Probability of CAD
by Symptoms, Gender and Age
Age Gender Typical/Definite
Angina Pectoris
Atypical/Probable
Angina Pectoris
Non-Anginal
Chest Pain
Asymptomatic
30-39 Males Intermediate Intermediate low (<10%) Very low (<5%)
30-39 Females Intermediate Very Low (<5%) Very low Very low
40-49 Males High (>90%) Intermediate Intermediate low
40-49 Females Intermediate Low Very low Very low
50-59 Males High (>90%) Intermediate Intermediate Low
50-59 Females Intermediate Intermediate Low Very low
60-69 Males High Intermediate Intermediate Low
60-69 Females High Intermediate Intermediate Low
High = >75% Intermediate = 15-75% Low = <15% Very Low = < 5%
17. Testing Algorithm contd..
Intermediate Probability
15% - 75%
Assess ECG and
Exercise Tolerance
Normal ECG
Can exercise
Treadmill test
Duke score
Negative
No more testing
Positive
Abnormal ECG or
Can’t exercise
MPI or ESE or CSE
Angiography
18. EXERCISE PROTOCOLS
• The exercise protocol should be progressive with
even increments in speed whenever possible.
• Smaller,even and more frequent work increments
are preferable to larger,uneven,and less frequent
increases,because the former yield a more
accurrate estimations of exercise capacity.
• The protocol should include a suitable recovery or
cool down period
19. EXERCISE PROTOCOLS
• In general, 6 to 12 minutes of continuous
progressive exercise during which the
myocardial oxygen demand is elevated to the
patient’s maximal level is optimal for diagnostic
and prognostic purposes.
• Dynamic protocols most frequently are used to
asses to cardiovascular reserve,and those
suitable for clinical testing should include a low
intensity warm-up phase
20. GENERAL CONCERNS PRIOR TO
EXERCISE TEST.
• Safety precautions and equipment needs.
• Patient preparation.
• Choosing a test type/protocol.
• Patient monitoring.
• Reasons to terminate test
• Post test monitoring.
21. SAFETY PRECAUTIONS AND
EQUIPMENT.
• The treadmill should have front and side rails
for subjects to steady themselves.
• It should be calibrated monthly.
• An emergency stop button should be readily
available to the staff only.
• Exercise test should be performed under the
supervision of a physician who has been
trained to conduct exercise test.
22.
23.
24. PRETEST PREPARATION
• Any history of light headedness or fainting
while exercising should be asked.
• Family history and general medical
history,taking note any considerations that
may increase the risk of sudden death.
• A brief physical examination should also b
performed prior to testing.
25. PATIENT’S PREPARATION
• The Subject should be instructed not to eat or
smoke or take caffeinated beverages atleast 2 -4
hrs prior to the test.
• Unusual physical exertion should be avoided before
testing.
• Specific questions should determine which drugs
are being taken.Medications should be brought
along.
• Wear comfortable shoes and loose- fitting clothes
26. PATIENT’S PREPARATION
• Advise patient about the risk and benefits of the
procedure
• A written informed consent form is usually required
• A standard 12-lead ECG is usually obtained
• The ECG should be obtained and blood pressures
recorded in both positions,and patients should be
instructed on how to perform the test
• Room temperature should be between 18 and 22
degrees and humidity less than 60%
27. PATIENT’S PREPARATION
• Patients skin preparation for electrodes placement
also very important
• Hyperventilation should be avoided before testing
.Subjects with or without disease can exhibit ST
segments changes with hyperventilation.
• The heart rate,blood pressure and ECG should be
recorded at the end of each stage of the
exercise,immediately before and immediately after
stopping the exercise,at the onset of an ischaemic
response.
28. VARIOUS TREADMILL PROTOCOLS
• BRUCE
• MODIFIED BRUCE
• ASYMPTOMATIC CARDIAC ISCHAEMIA PILOT
(ACIP)
• MODIFIED ACIP
• CORNELL
• BALKE WARE
• NAUGHTON
• WEBER.
29. BRUCE PROTOCOL
• Most common and widely adopted.
• Large diagnostic and prognostic data base has
been published.
• The Bruce multistage maximal treadmill
protocol has 3-minute periods to allow
achievement of a steady state before
workload is increased for next stage.
30. MODIFIED BRUCE PROTOCOL
• Starts at a lower workload than the standard
test.
• Typically used for elderly or sedentary patients
• The first two stages of the modified Bruce test
are performed at a 1.7mph and 0% grade and
1.7mph 5% grade.
• The third stage correspond the first stage of the
standard Bruce test protocol.
33. ACIP PROTOCOL.
• The asymptomatic Cardiac Ischaemia Pilot protocol
use 2-minute stages,with 1.5-MET increments
between stages after 1min warm up stages with 1-
MET increments.
• Developed to test patients with established CAD.
• Result in a linear increase in heart rate
and,distributing the time to occurrence of ST
segment depression over a wider range heart rate
and exercise time than protocols with more abrupt
increaments in workload between stages.
34. MODIFIED ACIP(mACIP) PROTOCOL
• The m ACIP protocol produces a similar
aerobic demand as the standard ACIP protocol
for each minute of the exercise.
• Well suited for short or older individuals who
cannot keep up with a working speed of
3mph
35. NAUGHTON AND WEBER PROTOCOLS
• Use 1 to 2 minute stages with 1-MET
increments between stages.
• These protocol is more suitable for patients
with limited exercise tolerance,such as
patients with compensated heart failure
36.
37. Contraindications for ETT
Absolute
• Acute myocardial infarction (within 2 days)
• Symptomatic severe aortic stenosis
• High risk unstable angina
• Acute pulmonary embolus or pulmonary infarction
• Acute aortic dissection
• High-risk unstable angina
• Uncontrolled cardiac arrhythmias
• Symptomatic severe aortic stenosis
• Uncontrolled symptomatic heart failure
• Acute pulmonary embolus or pulmonary infarction
• Acute myocarditis or pericarditis
• Acute aortic dissection
38. Contraindications for ETT
Relative
Left main coronary stenosis
Moderate stenotic valvular heart disease
Severe systemic hypertension
HOCM and other outflow obstruction
Moderate stenotic valvular heart disease
Electrolyte abnormalitiesESevere arterial
hypertension
Tachy or Brady arrhythmias
HOCM and other outflow obstructions
Mental or physical impairment
High-degree atrio-ventricular block
39. RECOVERY AFTER EXERCISE
• If maximal sensitivity is to be achieved with an
exercise test,patients should be supine as
soon as possible during the post exercise
period(maximal wall stress.)
• A cool-down walk can be helpful in performing
test on patients with an established diagnosis
undergoing testing for other diagnostic
reasons-MI,CCF,valvular heart dx.
40. RECOVERY AFTER EXERCISE
• A cool down walk after the test can delay or
eliminate the appearance of ST segment
depression.
• Monitoring should continue for at least
5minutes after exercise or until changes
stabilize.
41. When to Terminate ETT ?
Absolute indications
• Drop in SBP of >10 mm Hg from baseline BP with accompanying evidence of
ischemia
• Moderate to severe angina.
• Moderate to severe angina
• Increasing nervous system symptoms ataxia, dizziness
• Signs of poor perfusion(cyanosis,pallor)
• Signs of poor perfusion (cyanosis or pallor)
• Technical difficulties in monitoring ECG or SBP
• Subjects’s desire to stop.
• Sustained ventricular tachycardia
• .
• Subject’s desire to stop; Sustained ventricular tachycardia
• ST elevation (≥1.0 mm) in leads without diagnostic Q waves
42. When to Terminate ETT ?
Relative indications
• Drop in SBP of ≥10 mm Hg BP without ischemia
• ST or QRS changes - ST depression (>2 mm of horizontal
or down sloping ST-segment ↓) or axis shift
• Arrhythmias VT, multifocal PVCs, triplets of PVCs, SVT,
• Heart block or brady arrhythmias, BBB or IVCD
• Fatigue, shortness of breath, wheezing, leg cramps,
• Increasing chest pain; Hypertensive response > 250/115
44. ECG CHANGES.
ST SEGMENT ANALYSIS
• ST SEGMENT DEPRESSION.
• In normal persons the PR,QRS AND QT intervals
shorten as the heart rate increases.
• J point or junctional depression is a normal
finding during exercise.
• In patients with myocardial ischaemia,however
,the ST segment usually becomes more
horizontal as the severity of the ischaemia
increases
45. ST DEPRESSION
• With progressive exercise,the depth of ST segment
depression may increase and the patient may
develop angina.
• In the immediate recovery phase, the ST segment
depression may persist,gradually returning to
baseline after 5 to 10mimutes
• In about 10% of patients,the ischaemiac response
may appear only in the recovery phase
• Patients should not leave the exercise room until the
post exercise EcG has returned to baseline
46. • POSITIVE TEST- A flat or downward sloping of
the ST segment >0.1mv(1mm) below baseline
and lasting more than 0.08sec.
47. 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.
Consistent with a severe
ischemic response.
Horizontal ST
50. ST ELEVATION
..ST segment elevation >0.1mv(1mm) lasting more
than 0.06sec is considered abnormal
…Without pathologic Q waves,exercise induced
ST elevation usually indicates either significant
proximal coronary stenosis or epicardial
coronary spasm.
…When pathologic Q Waves are present ST
elevation is usually indicative of significant wall
motion changes.
51.
52. Digoxin Abnormal ST depression (45%)
LVH Decreases the specificity of ETT
Resting ST depression Marker of MACE
LBBB ST depression has limited value
RBBB No effect; V3-V6 to be monitored
Beta blockers Decrease the Heart Rate response
Calcium Channel Block Decreased Chronotropic response
53. BLOOD PRESSURE AND HEART RATE
CHANGES.
• The normal blood pressure response is to increase
systolic blood pressure progressively with increasing
workloads to a peak response ranging from 160 to
200mmHg.
• Failure to increase SBP beyond 120mmhg or a
sustained decrease greater than 10mmhg or fall in
SBP below standing resting values during progessive
exercise is abnormal.
• Hypertensive response to exercise is when SBP rises
nore than 250mmhg or DBP rises more than
115mmg
54. • HEART RATE RESPONSE.
• Peak HR > 85% of maximal predicted for age.
• HR Recovery>12bpm erect
• HR Recovery > 18bpm supine
• Chronotropic incompetence occurs when there is
inability to increase heart to atleast 85% of
predicted.
• Decreases vagal tone leads to slow deceleration
of HR following exercise ceasation
55. REFERENCES
• Jameson ,Fauci et al,Harrison’s principles of internal
medicine,20th edition.
• Parven kumar,Michael Clark,Clinical medicine,8th edition
• Goldberger AL,Goldberger ZD,clinical
electrocardiography,9th edition.
• ACC/AHA guidelines for Exercise stress test.
• Nathanson LA et al ,ECG Wave maven,self assessment
programme for students and physician
• Nicki R,Brian R,et al,Davisons principles and practise of
medicine,21st edition.
• Mirvis DM,Goldbeger AL,Electrocardiography in Braunwalds
Heart Disease,A texttbook of cardiovascular medicine,11th
edition
56. CONCLUSION
• Exercise stress test is a very important aspect
of cardiovascular evaluation,especially in
suspected coronary artery disease.
• Patient selection and preparation is key in
obtaining maximum results.
• Good knowledge of ECG is very important in
result interpretation.
