Interpretation of
Clinical Exercise
Test Results
(Material from Chapter 4,
GETP 11th edit.)
Copyright © 2014 American College of Sports Medicine
Copyright © 2014 American College of Sports Medicine
Ventilatory Expired Gas
Responses to Exercise
• Direct measurement of ventilatory expired gas during
exercise provides a more precise assessment of exercise
capacity and prognosis and helps to distinguish causes of
exercise intolerance (often used in pulmonary patients).
• The combination of this technology with standard GXT
procedures is typically referred to as
.
• Maximal volume of oxygen
. consumed per unit time (VO2max)
or peak oxygen uptake (VO2peak) provides important
information about cardiorespiratory fitness and is a
marker of prognosis.
Copyright © 2014 American College of Sports Medicine
Recommendations for Supervision of
Exercise Testing
• Exercise testing of individuals at high risk can be
supervised by non-physician health care
professionals if the professional is specially trained
in clinical exercise testing with a physician
immediately available if needed.
• Exercise testing of individuals at moderate risk can be
supervised by non-physician health care professionals if
the professional is specially trained in clinical
exercise testing, but whether or not a physician must
be immediately available for exercise testing is
dependent on local policies and circumstances, the health
status of the patients, and the training and experience of
the laboratory staff.
Copyright © 2014 American College of Sports Medicine
GRADED EXERCISE TESTING
For conditions that preclude reliable diagnostic ECG information,
the exercise test may still provide useful information on:
• Exercise capacity
• Subjective symptomatology
• Pulmonary function
• Dysrhythmias
• The hemodynamic responses to exercise
Additional evaluative techniques such as ventilatory expired gas analysis,
echocardiography, or nuclear imaging can be added and are most often very
worthwhile in determining medical diagnosis.
Copyright © 2014 American College of Sports Medicine
IS THE ACSM CERTIFIED EP QUALIFIED TO PERFORM
MAXIMAL GXT’S ON CLINICAL POPULATIONS?
Conducting the Clinical Exercise Test
• Testing Staff
– Over the past several decades, there has been a
transition in many exercise testing laboratories from
tests being administered by physicians to nonphysician
allied health professionals, such as clinical exercise
physiologists (CEPS), nurses, physical therapists, and
physician assistants.
– According to the ACC and AHA, the nonphysician allied
health care professional who administers clinical
exercise tests should have cognitive skills similar to,
although not as extensive as, the physician who
provides the final interpretation
Copyright © 2014 American College of Sports Medicine
Exercise Testing as a Screening Tool for
Coronary Artery Disease
• The use of exercise testing in asymptomatic individuals may be
useful to health/fitness and clinical exercise professionals given its
ability to:
–
reflect general health,
–
identify normal and abnormal physiologic responses to
physical exertion,
–
provide information to more precisely design the exercise
prescription (Ex Rx), and
–
provide prognostic insight, especially among those with
multiple CVD risk factors.
Copyright © 2014 American College of Sports Medicine
Participant Instructions
• If the test is for functional or exercise prescription
purposes, patients should continue their
medication regimen on their usual schedule so
that the exercise responses will be consistent with
responses expected during exercise training.
Copyright © 2014 American College of Sports Medicine
Participant Instructions
• If the exercise test is for diagnostic purposes, it may
be helpful for patients to discontinue prescribed
cardiovascular medications, but only with physician
approval. Currently prescribed antianginal agents
alter the hemodynamic response to exercise and
significantly reduce the sensitivity of ECG
changes for ischemia. Patients taking intermediateor high-dose β-blocking agents may be asked to
taper their medication over a 2- to 4-d period to
minimize hyperadrenergic withdrawal responses.
Copyright © 2014 American College of Sports Medicine
Participant Instructions
• If the evaluation is on an outpatient basis,
participants should be made aware that the
exercise test may be fatiguing and that they may
wish to have someone accompany them to the
assessment to drive them home afterward.
Copyright © 2014 American College of Sports Medicine
Participant Instructions
• Participants should refrain from ingesting food, alcohol, or
caffeine or using tobacco products within 3 hours of testing.
• Participants should be rested for the assessment, avoiding
significant exertion or exercise on the day of the
assessment.
• Clothing should permit freedom of movement and include
walking or running shoes. Women should bring a loose
fitting, short-sleeved blouse that buttons down the front and
should avoid restrictive undergarments.
Copyright © 2014 American College of Sports Medicine
Copyright © 2014 American College of Sports Medicine
DUKE NOMOGRAM
1.
2.
3.
4.
5.
Mark ST  and angina level and connect the points.
Mark the point where this intersects the ischemia line.
Mark the exercise tolerance in METS.
Connect the ischemia reading mark with the exercise METs.
Read the estimated 5-year survival/annual mortality rate.
Copyright © 2014 American College of Sports Medicine
Interpretation of Responses to
Graded Exercise Testing
• Assessing the diagnostic, prognostic, and therapeutic
applications of the test
– Hemodynamics: Assessed by the heart rate and
systolic and diastolic blood pressure responses
– ECG waveforms: Particularly ST-segment displacement
and supraventricular and ventricular dysrhythmias
– Signs: Clinical signs of cardiopulmonary exercise
intolerance (e.g., ECG changes, drop in BP, pallor)
– Symptoms: Chest pain, dizziness, syncope, etc.
– Ventilatory gas exchange responses: VO2, METS,
RER
Copyright © 2014 American College of Sports Medicine
Electrocardiographic,
Cardiorespiratory, and Hemodynamic
Responses to Exercise Testing and
Their Clinical Significance
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1. ST-segment depression (ST↓): An abnormal ECG
response is defined as ≥1 mm of horizontal or
downsloping ST↓80 milliseconds (.08 seconds)
beyond the J-point, suggesting myocardial
ischemia.
2. ST-segment elevation (ST↑): ST↑ in leads
displaying a previous Q wave MI almost always
reflects an aneurysm or wall motion abnormality. In
the absence of significant Q waves, exerciseinduced ST ↑ often is associated with a fixed highgrade coronary artery stenosis.
Copyright © 2014 American College of Sports Medicine
Normal and Abnormal ST-Segment
Copyright © 2014 American College of Sports Medicine
13-79
ST-Segment Depression
• Slowly upsloping ST-segment depression should be
considered a borderline response, and added emphasis
should be placed on other clinical and exercise variables.
• ST-segment depression does not localize ischemia to a
specific area of myocardium.
• The more leads with (apparent) ischemic ST-segment
shifts, the more severe the disease.
• Must be in at least 3 consecutive cycles in the same lead
• Significant ST-segment depression occurring only in
recovery likely represents a true positive response and
should be considered an important diagnostic finding.
Copyright © 2014 American College of Sports Medicine
Exercise Testing for Disease Severity
and Prognosis
• The magnitude of ischemia caused by a coronary
lesion generally is:
– directly proportional to a) the degree of STsegment depression, b) the number of ECG leads
involved, and c) the duration of ST-segment
depression in recovery; and
– inversely proportional to the a) the ST slope, b) the
rate pressure product (RPP) at which the STsegment depression occurs, and c) the HRmax, SBP,
and metabolic equivalents (METS) achieved.
Copyright © 2014 American College of Sports Medicine
3. Supraventricular dysrhythmias: Isolated atrial
ectopic beats or short runs of SVT commonly occur
during exercise testing and do not appear to have any
diagnostic or prognostic significance for CVD. Many of
us have PAC’s (premature atrial beats) at rest and
during exercise.
Copyright © 2014 American College of Sports Medicine
4. Ventricular dysrhythmias:
- PVCs that increase in frequency, complexity, or both do
not necessarily signify underlying ischemic heart disease.
- Complex ventricular ectopy (including paired or multiform
PVCs) and runs of ventricular tachycardia (≥3 successive
beats) are likely to be associated with significant CVD and/
or a poor prognosis if they occur in conjunction with signs
and/or symptoms of myocardial ischemia in patients with a
history of sudden cardiac death, cardiomyopathy, or
valvular heart disease.
- Frequent ventricular ectopy during recovery has been found
to be a better predictor of mortality than ventricular ectopy
that occurs only during exercise.
Copyright © 2014 American College of Sports Medicine
5. Heart rate (HR): The normal HR response to
progressive exercise is a relatively linear increase,
corresponding to 10 ± 2 beats ∙ MET−1 for physically
inactive subjects.
Chronotropic incompetence (flat or decreasing HR with
increasing intensity) may be signified by the following:
- A peak exercise HR that is >2 SD (≈20 beats · min−1) below
the age-predicted HRmax or an inability to achieve ≥85% of
the age-predicted HRmax for subjects who are limited by
volitional fatigue and are not taking β-blocker drugs
Heart rate during recovery: An abnormal (slowed) recovery
HR is associated with a poor prognosis. A normal HR recovery
has frequently been defined as a decrease ≤12 beats ∙ min−1 at
1 min (walking in recovery), or ≤22 beats ∙ min−1 at 2 min
(supine position in recovery).
Copyright © 2014 American College of Sports Medicine
• Achievement of age-predicted HRmax
should not be used as an absolute test
endpoint or as an indication that effort
has been maximal because of its high
inter-subject variability.
Copyright © 2014 American College of Sports Medicine
Blood Pressure Response
The normal BP response to dynamic upright
exercise consists of:
•A progressive increase in SBP
•No change or a slight decrease in DBP
•A widening of the pulse pressure
(SBP – DBP)
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SPECIFIC BLOOD PRESSURE
RESPONSES
• Hypertensive Response
• Hypotensive Response
• Blunted Response
• Post-exercise response
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6. Systolic blood pressure (SBP):
- The normal response to exercise is a progressive increase in
SBP, typically 10 ± 2 mm Hg ∙ MET−1 with a possible plateau
at peak exercise. Also see a widening of the pulse pressure.
- Exercise testing should be discontinued with SBP values of
>250 mm Hg.
- Exertional hypotension (SBP that fails to rise or falls [>10
mm Hg]) may signify myocardial ischemia and/or LV
dysfunction with associated symptoms. A maximal exercise
SBP of <140 mm Hg suggests a poor prognosis.
7. Diastolic blood pressure (DBP):
- The normal response to exercise is no change or a decrease
in DBP.
- A DBP of >115 mm Hg is considered an endpoint for exercise
testing.
Copyright © 2014 American College of Sports Medicine
Blood Pressure Response
• Although HRmax is comparable for men and women,
men generally have higher SBPs (~20 ± 5 mm Hg)
during maximal treadmill testing.
• The sex difference is no longer apparent after 70 yr.
• The rate pressure product, or double product (SBP 
HR), is an indicator of myocardial oxygen demand.
• Maximal double product values during exercise testing
are typically between 25,000 (10th percentile) and
40,000 (90th percentile).
Copyright © 2014 American College of Sports Medicine
8. Anginal symptoms (Typical and Atypical):
- Can be graded on a scale of 1–4, corresponding
to perceptible but mild, moderate, moderately
severe, and severe, respectively.
- A rating of 3 (moderately severe) generally
should be used as an endpoint for exercise testing.
Copyright © 2014 American College of Sports Medicine
9. Cardiorespiratory fitness:
- Average values of VO2max /VO2peak expressed as
. sedentary men and
METs, expected .in healthy
women, can be predicted from one of several
regression equations
- Recent meta-analysis suggests each 1 MET
increase in aerobic capacity equates to 13%
15% decrease in all-cause mortality and
and cardiovascular events, respectively
Copyright © 2014 American College of Sports Medicine
Copyright © 2014 American College of Sports Medicine
Exercise Testing as a Screening Tool for
Coronary Artery Disease
• Bayes’ theorem
– Bayes’ theorem states that the post-test probability
of having a disease is determined by the disease
probability before the test and the probability that the
test will provide a true result.
– The probability of a patient having a disease before
the test is most importantly related to the presence of
symptoms (particularly chest pain characteristics), in
addition to the patient’s age, sex, and the presence of
major CVD risk factors.
Copyright © 2014 American College of Sports Medicine
Diagnostic Value of Exercise Testing
• Sensitivity
– The percentage of patients tested with
known CVD who demonstrate significant
ST-segment (i.e., positive or abnormal)
changes
• Specificity
– The percentage of patients without CVD
who demonstrate non-significant (i.e.,
negative or normal) ST-segment changes
Copyright © 2014 American College of Sports Medicine
Copyright © 2014 American College of Sports Medicine
Diagnostic Value of Exercise Testing
– A measure of how accurately a test result
(positive or negative) correctly identifies the
presence or absence of CVD in tested patients
– Cannot be estimated directly from a test’s
specificity or sensitivity because it depends on
the prevalence of disease in the population
being tested
Copyright © 2014 American College of Sports Medicine
FALSE POSITIVE AND NEGATIVE TESTS
• FALSE POSITIVE
– The ECG during graded exercise testing
shows abnormalities (e.g., ST ) when
there is no disease present.
• FALSE NEGATIVE
– The ECG during graded exercise testing
shows no abnormalities (e.g., ST )
when in fact there is disease present.
Copyright © 2014 American College of Sports Medicine
Copyright © 2014 American College of Sports Medicine
Box 4.6. Causes of False Negative Test Results
• Failure to reach an ischemic threshold
• Monitoring an insufficient number of leads to detect ECG
changes
• Failure to recognize non-ECG signs and symptoms that
may be associated with underlying CVD (e.g., exertional
hypotension)
• Angiographically significant CVD compensated by
coronary collateral circulation (growth of collateral
vessels)
• Musculoskeletal limitations to exercise preceding
cardiac abnormalities
• Technical or observer error
Copyright © 2014 American College of Sports Medicine
Copyright © 2014 American College of Sports Medicine
Box 4.7. Causes of Abnormal ST-Segment
Changes in the Absence of Obstructive
Cardiovascular Disease (False Positive Test)
• ST segment depression > 1.0 mm at rest
• Left ventricular hypertrophy
• Accelerated conduction defects (e.g., Wolff-ParkinsonWhite syndrome)
• Digitalis therapy (the drug Lanoxin or Digoxin)
• Non-ischemic cardiomyopathy
• Hypokalemia
• Vasoregulatory abnormalities
Copyright © 2014 American College of Sports Medicine
TABLE 2 (cont.) Causes of Abnormal ST-Segment
Changes in the Absence of Obstructive
Cardiovascular Disease (False Positive Test)
• Mitral valve prolapse
• Pericardial disorders
• Technical or observer error
• Coronary spasm
• Anemia
NOTE: Selected variables may simply be associated with,
rather than be direct causes, of abnormal test results.
Copyright © 2014 American College of Sports Medicine
•
How likely is the test to detect the
presence of a characteristic in someone with the
characteristic (e.g., CVD)?
•
How likely is the test to detect the
absence of a characteristic in someone without the
characteristic (e.g., CVD)?
•
How likely is someone
with a positive (abnormal) test result to actually have
the characteristic (e.g., CVD)?
•
How likely is someone
with a negative (normal) test result to actually not
have the characteristic (e.g., CVD)?
Copyright © 2014 American College of Sports Medicine
TEST SENSITIVITY
• TP/(TP + FN) x 100 = the % of patients
with CVD who have a positive test
TEST SPECIFICITY
• TN/(TN + FP) x 100 = the % of patients
without CVD who have a negative test
CVD, cardiovascular disease; FN, false negative (negative
exercise test and CVD); FP, false positive (positive exercise test
and no CVD); TN, true negative (negative exercise test and no
CVD); TP, true positive (positive exercise test and CVD).
Copyright © 2014 American College of Sports Medicine
Copyright © 2014 American College of Sports Medicine
+ PREDICTIVE VALUE (+ TEST)
• TP/(TP + FP) x 100 = the % of patients
with a positive test who have CVD
- PREDICTIVE VALUE (- TEST)
• TN/(TN + FN) x 100 = the % of patients
with a negative test who do not have
CVD
CVD, cardiovascular disease; FN, false negative (negative
exercise test and CVD); FP, false positive (positive exercise test
and no CVD); TN, true negative (negative exercise test and no
CVD); TP, true positive (positive exercise test and CVD).
Copyright © 2014 American College of Sports Medicine
EXAMPLES: TEST SPECIFICITY +
PREDICTIVE VALUE
• Muffy is the director of a cardiac testing laboratory
in the outer regions of upper Mongolia. She has
tested 5000 patients in her lab to date.
• Of these patients, 4500 had a positive GXT ECG and
had CAD when verified with follow-up coronary
angiogram results.
• 200 patients had a false negative GXT ECG, when in
fact they actually did have CAD verified with
follow-up coronary angiogram results.
• 300 patients had a false positive GXT ECG test,
when in fact they actually did not have CAD verified
with follow-up coronary angiogram results.
Copyright © 2014 American College of Sports Medicine
EXAMPLE: TEST SENSITIVITY
= TP/(TP + FN) x 100 = the %
of patients with CVD who have a positive test
• 4500/(4500 + 200) ~ 96%
•
: Muffy does a great job of testing her
patients in upper Mongolia for diagnosis of
CAD!
Copyright © 2014 American College of Sports Medicine
EXAMPLE: PREDICTIVE VALUE (+ TEST)
= TP/(TP + FP) x 100 = the
% of patients with a positive test who have CVD
• 4500/(4500 + 300) ~ 94%
•
: Muffy does a decent job of predicting
CAD from her stress tests in her Mongolia lab!
Copyright © 2014 American College of Sports Medicine
Copyright © 2014 American College of Sports Medicine