Transcript Chapter 5 Clinical Exercise Testing

Chapter 5
Clinical Exercise Testing
Copyright © 2014 American College of Sports Medicine
Indications and Purposes
The exercise test may be used for
diagnostic (identify abnormal physiologic
responses), prognostic (identify adverse
events), and therapeutic (gauge impact of a
given intervention) purposes as well as for
physical activity counseling and to design
an exercise prescription (see Chapters 7
and 9).
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25. Gibbons RJ, Balady GJ, Bricker JT, et al. Committee to Update the 1997 Exercise Testing Guidelines.
ACC/AHA 2002 guideline update for exercise testing: summary article. A report of the American College of
Cardiology/American Heart Association Task Force on Practice Guidelines (Committee to Update the 1997
Exercise Testing Guidelines). J Am Coll Cardiol. 2002;40(8):1531–40.
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Diagnostic Exercise Testing (cont.)
• Patients with a high probability of disease (e.g.,
typical angina, prior coronary revascularization,
myocardial infarction) are tested
– to assess residual myocardial ischemia,
– to assess threatening ventricular
arrhythmias, and
– for prognosis rather than for diagnostic
purposes.
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FIGURE 5.1. Impact of positive or negative ST-segment response during GXT on the posttest probability of
angiographically significant CVD in subjects with different pretest probabilities. CAD, coronary artery disease.
Reprinted with permission from (63).
63. Patterson RE, Horowitz SF. Importance of epidemiology and biostatistics in deciding clinical strategies for
using diagnostic tests: a simplified approach using examples from coronary artery disease. J Am Coll Cardiol.
1989;13(7):1653–65.
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Exercise Testing for Disease Severity
and Prognosis
• The magnitude of ischemia caused by a coronary lesion
generally is
– directly proportional to the degree of ST-segment
depression, the number of ECG leads involved, and
the duration of ST-segment depression in recovery;
and
– inversely proportional to the ST slope, the rate
pressure product (RPP) at which the ST-segment
depression occurs, and the heart rate maximum,
SBP, and metabolic equivalents achieved.
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Exercise Testing After
Myocardial Infarction
• Exercise testing after myocardial infarction can be
performed
– before or soon after hospital discharge for
prognostic assessment,
– for exercise prescription,
– for evaluation of further medical therapy, and
– for interventions including coronary
revascularization.
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Exercise Testing After
Myocardial Infarction (cont.)
• Submaximal exercise testing provides sufficient data to
assess the effectiveness of current pharmacologic
management (see Appendix A) as well as activities of
daily living and early ambulatory exercise therapy
recommendations.
• Symptom-limited graded exercise tests are considered
safe and appropriate early after discharge (~14–21 d)
for exercise prescription and physical activity
counseling and further assessment of pharmacologic
management efficacy.
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Functional Exercise Testing
Functional exercise testing is valuable for
– physical activity counseling,
– exercise prescription,
– disability assessment,
– helping to estimate prognosis, and
– return to work evaluation (if occupation requires
aerobic activity).
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FIGURE 5.2. Nomograms of percent normal exercise capacity in men with suspected coronary artery disease who were referred
for clinical exercise testing and in apparently healthy men and women. METs, metabolic equivalents. Reprinted with permission
from (51) and (28). (continued)
28. Gulati M, Black HR, Shaw LJ, et al. The prognostic value of a nomogram for exercise capacity in women. N Engl J Med.
2005;353(5):468–75.
51. Morris CK, Myers J, Froelicher VF, Kawaguchi T, Ueshima K, Hideg A. Nomogram based on metabolic equivalents and age for
assessing aerobic exercise capacity in men. J Am Coll Cardiol. 1993;22(1):175–82.
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FIGURE 5.2. (continued) Nomograms of percent normal exercise capacity in men with suspected coronary
artery disease who were referred for clinical exercise testing and in apparently healthy men and women.
METs, metabolic equivalents. Reprinted with permission from (51) and (28).
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FIGURE 5.2. (continued) Nomograms of percent normal exercise capacity in men with suspected coronary
artery disease who were referred for clinical exercise testing and in apparently healthy men and women.
METs, metabolic equivalents. Reprinted with permission from (51) and (28).
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Exercise Test Modalities
• The treadmill is the most common exercise testing
mode used in the United States.
• Treadmills in clinical exercise laboratories should
be electronically driven, allow for a wide range of
speed (1–8 mph or 1.61–12.8 km ∙ h−1) and grade
(0%–20%), and be able to support a body weight of
at least 350 lb (159.1 kg).
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Exercise Test Modalities (cont.)
• The treadmill should have handrails for balance and
stability; but given the negative impact tight gripping of the
handrails can have on both the
. accuracy of estimated
exercise capacity (estimated
. VO2peak with handrail gripping
is greater than measured VO2peak) and the quality of the
ECG recording, handrail use should be discouraged or
minimized to the lowest level possible when maintaining
balance is a concern.
• An emergency stop button should be readily visible and
available to both the subject undergoing testing and
supervising staff .
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Exercise Test Modalities (cont.)
• Cycle ergometers are the most common exercise
testing modes used in many European countries.
• Cycle ergometry is less expensive and requires less
space than treadmill testing and is a viable alternative
to treadmill testing in individuals with obesity and those
who have orthopedic, peripheral vascular, and/or
neurologic limitations.
• The cycle ergometer must include handlebars and an
adjustable seat, allowing for the knee to be flexed ~25
degrees of full extension in a given subject.
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Exercise Test Modalities (cont.)
• Incremental work rates on an electronically
braked cycle ergometer are more sensitive than
mechanically braked ergometers because the
work rate can be maintained over a wide range
of pedal rates.
• Because there is less movement of the
patient’s arms and thorax during cycling, it is
easier to obtain better quality ECG recordings
and blood pressure measurements.
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Exercise Test Modalities (cont.)
• However, stationary cycling is an unfamiliar method of
exercise for many and is highly dependent on patient
motivation.
• The test may end prematurely (i.e., because of localized leg
fatigue) before a cardiopulmonary endpoint has been
achieved.
• Lower values for maximal oxygen consumption during cycle
ergometer testing (vs. treadmill testing) can range from 5%
to 25%, depending on the participant’s habitual activity,
physical conditioning, leg strength, and familiarity with
cycling.
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Exercise Test Modalities (cont.)
• Arm ergometry is an alternative method of exercise
testing for patients who cannot perform leg exercise.
• Because a smaller muscle mass is used during arm
ergometry, maximal oxygen consumption during arm
exercise is generally 20%–30% lower than that
obtained during treadmill testing.
• Although this test has diagnostic use, it has been
largely replaced by the nonexercise pharmacologic
stress techniques that are described later in this
chapter.
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Exercise Test Modalities (cont.)
• Arm ergometer tests can be used for
physical activity counseling and exercise
prescription for certain disabled
populations (e.g., spinal cord injury).
• Arm ergometer test can be used by
individuals who perform primarily dynamic
upper body work during occupational or
leisure time activities.
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Exercise Protocols
• The protocol employed during an exercise test
should consider
– the purpose of the evaluation,
– the specific outcomes desired, and
– the characteristics of the individual being tested
(e.g., age, symptomatology).
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Exercise Protocols (cont.)
• Most common exercise test protocols (see
Figure 5.3)
– Bruce
– Ellestad
– Naughton
– Balke-Ware
– Ramp
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Exercise Protocols (cont.)
• Advantages of the ramp approach include
– avoidance of large and unequal increments in workload,
– uniform increase in hemodynamic and physiologic
responses,
– more accurate estimates of exercise capacity and
ventilatory threshold,
– individualized test protocol (ramp rate), and
– targeted test duration (individualized ramp protocols).
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Measurements During Exercise Testing
• Common variables assessed during clinical exercise testing
include
– heart rate
– ECG changes,
– blood pressure,
– subjective ratings,
– signs and symptoms, and
– expired gases and ventilatory responses.
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16. Brubaker PH, Kaminsky LA, Whaley MH. Coronary Artery Disease: Essentials of Prevention and
Rehabilitation Programs. Champaign (IL): Human Kinetics; 2002. 364 p.
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Heart Rate and Blood Pressure (cont.)
• Heart rate and blood pressure responses
should be measured before, during, and after
the GXT.
• A standardized procedure should be adopted
for each laboratory so that baseline
measures can be assessed more accurately
when repeat testing is performed.
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Box 5.1 Potential Sources of Error in Blood
Pressure Assessment
• Inaccurate sphygmomanometer
• Improper cuff size
• Auditory acuity of technician
• Rate of inflation or deflation of cuff pressure
• Experience of technician
• Reaction time of technician
• Faulty equipment
• Improper stethoscope placement or pressure
• Background noise
• Allowing patient to hold treadmill handrails or flex elbow
• Certain physiologic abnormalities (e.g., damaged brachial artery, subclavian
steal syndrome, arteriovenous fistula)
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Subjective Ratings and Symptoms
• The measurement of perceptual responses during exercise
testing can provide useful clinical information.
• Somatic ratings of perceived exertion (RPE) (see Chapters
4,7, and 10) and/or specific symptomatic complaints include
– degree of chest pain, burning, and discomfort;
– dyspnea;
– light-headedness; and
– leg discomfort/pain.
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FIGURE 5.4. Frequently used scales for assessing the patient’s level of angina (top), claudication (middle),
and dyspnea (bottom).
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Gas Exchange and Ventilatory Responses
• Currently, the combination of standard GXT
procedures and ventilatory expired gas analysis
(cardiopulmonary exercise testing) is the clinical
standard for patients with CHF being assessed for
transplantation candidacy and individuals with
unexplained exertional dyspnea.
• The direct measurement of oxygen uptake is more
reliable and reproducible than estimated values
from treadmill or cycle ergometer work rates.
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Arterial Blood Gas Assessment
During Exercise
• In patients who present with unexplained exertional
dyspnea, pulmonary disease should be considered
as a potential underlying cause.
• It is important to quantify gas partial pressures in
these patients because oxygen desaturation may
occur during exertion.
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Box 5.2 Indications for Terminating Exercise Testing
ABSOLUTE INDICATIONS
• Drop in systolic BP of ≥10 mm Hg with an increase in work rate, or if
systolic BP decreases below the value obtained in the same position
prior to testing when accompanied by other evidence of ischemia
• Moderately severe angina (defined as 3 on standard scale)
• Increasing nervous system symptoms (e.g., ataxia, dizziness, or near
syncope)
• Signs of poor perfusion (cyanosis or pallor)
• Technical difficulties monitoring the ECG or SBP
• Subject’s desire to stop
• Sustained ventricular tachycardia
• ST elevation (+1.0 mm) in leads without diagnostic Q waves (other
than V1 or aVR)
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Box 5.2 Indications for Terminating Exercise Testing (cont.)
RELATIVE INDICATIONS
•
Drop in systolic BP of ≥10 mm Hg with an increase in work rate, or if systolic BP below the
value obtained in the same position prior to testing
•
ST or QRS changes such as excessive ST depression (>2 mm horizontal or downsloping STsegment depression) or marked axis shift
•
Arrhythmias other than sustained ventricular tachycardia, including multifocal PVCs, triplets of
PVCs, supraventricular tachycardia, heart block, or bradyarrhythmias
•
Fatigue, shortness of breath, wheezing, leg cramps, or claudication
•
Development of bundle-branch block or intraventricular conduction delay that cannot be
distinguished from ventricular tachycardia
•
Increasing chest pain
•
Hypertensive response (SBP of >250 mm Hg and/or a DBP of >115 mm Hg).
aVR, augmented voltage right; BP, blood pressure; DBP, diastolic blood pressure; ECG, electrocardiogram; PVC,
premature ventricular contraction; SBP, systolic blood pressure; V1, chest lead I. Reprinted with permission from
(25). 25. Gibbons RJ, Balady GJ, Bricker JT, et al. Committee to Update the 1997 Exercise Testing Guidelines.
ACC/AHA 2002 guideline update for exercise testing: summary article. A report of the American College of
Cardiology/American Heart Association Task Force on Practice Guidelines (Committee to Update the 1997 Exercise
Testing Guidelines). J Am Coll Cardiol. 2002;40(8):1531–40.
Copyright © 2014 American College of Sports Medicine
Postexercise Period
• Regardless of the postexercise procedures
(active vs. passive recovery), monitoring should
continue for at least 6 min after exercise or until
ECG changes return to baseline and significant
signs and symptoms resolve.
• ST-segment changes that occur only during the
postexercise period are currently recognized to
be an important diagnostic part of the test.
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Postexercise Period (cont.)
• HR and BP should also return to near
baseline levels before discontinuation
of monitoring.
• The HR recovery from exercise is an
important prognostic marker that
should be recorded (see Chapter 6).
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Imaging Modalities
• Exercise echocardiography
• Cardiac radionuclide imaging
• Pharmacologic stress testing
• Computed tomography
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The Bottom Line
The ACSM Clinical Exercise Testing Key Points are as follows:
• Although a clinical exercise test may not be indicated for most individuals
about to begin an exercise program (see Chapter 2), the high value of
information obtained from this procedure is not debatable.
• Aerobic capacity may be one of the single best prognostic markers in all
individuals regardless of health status.
• Standard clinical exercise testing is well accepted for the assessment of
individuals with signs and/or symptoms suggestive of CVD.
• The use of cardiopulmonary exercise testing, which combines standard clinical
exercise testing with simultaneous ventilatory expired gas analysis, is common
practice in patients with CHF as well as those with unexplained exertional
dyspnea.
• The recent recognition that appropriately trained nonphysician personnel can
safely perform a clinical exercise test may result in the expanded use of this
valuable procedure in various clinical settings.
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