Transcript continued - Human Kinetics

C H A P T E R
5
Graded Exercise Testing and
Exercise Prescription
Keteyian
Chapter 05
Commonly Used Terms
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Stress ECG/EKG
Regular stress test
Cardiac stress test
Graded exercise test (GXT)
Sign- and symptom-limited GXT (Sx-GXT)
Why Learn About Exercise Testing and the Principles
and Elements Associated With Conducting Such
Testing?
Because the same principles and elements
are used in conjunction with many similar
and more complex diagnostic and
prognostic procedures
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Stress ECG only
Cardiopulmonary exercise (CPX)
Exercise stress echocardiogram
Exercise stress nuclear test or myocardial perfusion
imaging (MPI)
– Pharmacologic stress
If Resting ECG Is Abnormal or Patient Cannot
Exercise, Consider Another Method to Assess
Presence of CAD
• Stress ECG with imaging
– ECG plus echocardiogram (stress echo)
• Allows for assessment of wall motion abnormalities
– ECG with radionuclide imaging (stress nuclear or MPI)
• Allows for assessment of distribution of blood flow
Another Method to Stress the Myocardium to
Reveal Reversible Myocardial Ischemia, Often
Used in Patients Who Cannot Exercise
• Pharmacologic stress with imaging (echo or
myocardial perfusion)
– Beta agonists (e.g., dobutamine)
• Increase myocardial oxygen consumption by
increase in inotropicity and chronotropicity
– Redistribute blood flow (adenosine, dypiridamole)
Stress ECG Cost
• Cost and accessibility
– Stress ECG (~$450) < stress echo < stress
radionuclide (using exercise or pharmacology to
induce stress) < computed tomography with
angiogram < cardiac catheterization with angiogram
Seven Elements for Graded Exercise
Testing
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2.
3.
4.
Five pretest considerations
Appearance and quantification of Sx
ECG responses during exercise
Blood pressure responses during exercise and
recovery
5. HR responses during exercise and recovery
6. Assessment of functional capacity
7. Interpretation of findings (six components) and
generation of report
Five Pretest Considerations
1. Testing personnel
2. Informed consent
3. General interview and physical examination
(includes risk factors and medicine
reconciliation)
4. Pretest instructions and subject
preparation for ECG
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4 h before pretest instruction
Immediately before
5. Selection of exercise protocol and modality
1. Testing Personnel
• Exercise technician (exercise specialist,
cardiovascular technician, exercise
physiologist)
• Test supervision and initial interpretation of
test data (clinical exercise physiologist,
physical therapist, registered nurse, nurse
practitioner, physician assistant, physician)
• Final interpretation of test data (physician)
• Required versus suggested certifications
(ACC, ACSM)
(continued)
1. Testing Personnel (continued)
• Knowledge of indications and
contraindications; ability to safely conduct
test, select proper protocol and test mode,
identify and respond to clinical signs and
symptoms appropriately, interpret test
responses and findings correctly
• Safety
– Risk for combined death or a major event requiring
hospitalization = 0.1 to 0.9 per 1,000 tests
– Death = 0.1 per 1,000 tests
2. Informed Consent
• A brief explanation of why the test is being
done and test procedures
• Explanation of risks
– CV: minor and major
– Orthopedic
– Metabolic related (diabetes: hypoglycemia, wound
care)
• Patient explains or verbalizes all of these
back to test supervisor
• A “meeting of the minds”
3. General Interview and Examination
• This includes determining risk factors and
medicine reconciliation.
One Objective
Indications
• Assess chest pain and like symptoms to assist
in the diagnosis of coronary heart disease or
other medical problem
– Test usefulness is greatest among those with an intermediate
(not low and not high) pretest likelihood of having heart disease
• Identify a patient’s future risk or prognosis
– Symptoms
– ST-segment changes
• Extent and magnitude
• Time to onset
• Time to resolution
– Functional capacity
(continued)
Indications (continued)
• Evaluate pacemaker, heart rate, or blood
pressure response to exertion
• Evaluate exercise capacity for return-to-work
guidelines and disability determination
• Determine effect of an intervention
• Prescribe exercise
Absolute Contraindications
• Myocardial infarction (MI) within prior 2 d or
other acute cardiac event
• Change in ECG suggesting MI or other acute
event
• Unstable angina
• Symptomatic, severe aortic stenosis
• Decompensated, symptomatic heart failure
(continued)
Absolute Contraindications
(continued)
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Acute pulmonary embolism or infarction
Acute myocarditis or pericarditis
Acute infection
Suspected or known ventricular or dissecting
aortic aneurysm
Relative Contraindications
• Left main stenosis
• Moderate valvular stenotic disease
• Severe arterial hypertension (systolic >200
mmHg or diastolic >11 mmHg)
• Tachycardia at rest or marked bradycardia
(continued)
Relative Contraindications
(continued)
• Hypertrophic cardiomyopathy or other forms
of outflow tract obstruction
• Mental or physical impairment that limits
ability to exercise or is worsened with
exercise
• High-degree atrioventricular block (Mobitz
type II or third degree)
• Uncontrolled metabolic disease or electrolyte
abnormality
ACSM Criteria for Who Does and Does Not Need
a GXT Before Exercising or Starting an Exercise
Program
• No = low risk
– Men <45 with less than two CV risk factors
– Women <55 with less than two CV risk factors
• Yes = moderate risk
– Men >44 with two or more CV risk factors
– Women >54 with two or more CV risk factors
• Yes = high risk
– One or more signs or symptoms of CV or pulmonary or
metabolic disease
– Prior history of CV or pulmonary or metabolic disease
4. Subject Preparation
• Pretest instructions
– Clothing
• Comfortable and belted
• Shoes versus heel-less versus stocking feet
– Continue medications as prescribed or not and timing of
medications
• Reason for test (diagnostic, prognostic, exercise
program)
– Food and water
– Substances
• ETOH
• Cigarettes
• Marijuana
• Other recreational drugs
(continued)
4. Subject Preparation (continued)
• Skin preparation
– Determine quality of ECG (muscle and motion artifact)
– Eliminate oils and outer layer of epidermis using
chemicals and abrading skin; produce erythema
• Electrode placement
– 10 sites: 4 modified limb leads and standard 6
precordial leads
– Alter site for pacer implant or ICD implant
Placement of Electrodes
5. Selection of Protocol and Modality
• Select protocol
– Steady state versus ramp
– Maximal versus submaximal
– Try to match work rate increments (in estimated METs)
to patient capabilities (e.g., walk a flight of stairs)
– Complete test in 8 to 12 min
– Use of a common (vs. less common) protocol allows the
clinician to compare a patient’s test results to others
– Repeat testing on a patient should try to use the same
protocol, when possible, to allow results to be
compared between tests
(continued)
5. Selection of Protocol and Modality
(continued)
• Select mode (treadmill, bike, arm ergometer,
other)
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Provide quantified, incremental, graded work
Athletes: specificity of testing and training
Occupational concerns
Accommodate patient needs
• Orthopedic
• Body habitus
• Gait and balance
Commonly Used Protocols
See table 5.1 on commonly used treadmill and
bicycle protocols.
Seven Elements for Graded Exercise
Testing
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Pretest considerations
Appearance and quantification of Sx
ECG responses during exercise
Blood pressure responses during exercise
and recovery
• HR responses during exercise and recovery
• Assessment of functional capacity
• Interpretation of findings (six components)
and generation of report
Appearance and Quantification of
Symptoms
• Maintain regular communication between staff and
patient.
• At minimum, at the end of each stage assess patient’s
rating of perceived exertion (scale 6-19) and any
clinical symptoms (excessive dyspnea, claudication,
angina).
• May need handheld posters for testing done in
combination with mouthpiece or mask to measure
indirect spirometry.
• Accommodate through translation other common
languages.
Angina, Dyspnea, and Peripheral
Vascular Disease Scales
See table 5.2 for angina, dyspnea, and
peripheral vascular disease scales.
Seven Elements for Graded Exercise
Testing
• Pretest considerations
• Appearance and quantification of Sx
• ECG responses at rest, during exercise, and in
recovery
• Blood pressure responses during exercise and
recovery
• HR responses during exercise and recovery
• Assessment of functional capacity
• Interpretation of findings (six components) and
generation of report
Benefits of Stress ECG
• Stress ECG alone can be useful for
determining if resting ECG is free of
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LVH
LBBB
ST depression >1 mm
Pacemaker
Figure 5.2
Figure 5.3
ECG Responses During Exercise
• Rate
• Amplitude of waves
– Normal: decrease in total QRS amplitude
– Ischemia: increase in QRS amplitude
• Conduction velocity
– Normal: PR and QRS durations shorten due to
catecholamine-induced increase in conduction velocity
• Arrhythmia
– Clinical importance of supraventricular versus ventricular
(continued)
ECG Responses During Exercise
(continued)
• ST-segment changes
– Lead V5 most diagnostic for detecting coronary artery
disease
– Criteria for a positive test for ischemia:
• One or more millimeters of horizontal or downsloping
ST depression at 0.08 s past the J point or 1.5 or
more mm of upsloping ST depression at 0.08 s past
the J point
– Likelihood of coronary disease increases if more leads
are involved, as magnitude of ST depression increases,
and if ST depression develops sooner during exercise
and/or resolves later in recovery
Figure 5.3
Seven Elements for Graded Exercise
Testing
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Pretest considerations
Appearance and quantification of Sx
ECG responses during exercise
Blood pressure responses during exercise and
recovery
• HR responses during exercise and recovery
• Assessment of functional capacity
• Interpretation of findings (six components) and
generation of report
Blood Pressure Responses During
Exercise
• Hypertensive response: >210 mmHg at peak
• Hypertensive response: >90 mmHg at peak
• Hypotensive response:
 10 mmHg decrease in SBP below prior value with evidence of
ischemia
 Decrease below resting SBP
Note:
1. Slight decrease in systolic early during exercise or at peak
exercise may not indicate a true hypotensive response.
2. Evaluate blood pressure findings within the context of any possible
confounding effects of medications (afterload-reducing agents).
Blood Pressure Responses During
Exercise and Recovery
• Hypertensive systolic response: >210 mmHg
at peak
– Two- to threefold increased future risk for developing
hypertension at rest
• Abnormal recovery BP response
– By 3 min into recovery, systolic blood pressure should
have dropped by >10% from peak blood pressure;
recovery systolic blood pressure at 3 min/peak systolic
blood pressure <0.9 (e.g., 140/152 = 0.92)
Ankle–Brachial Index
• Normal ABI: >0.9
– Left arm = 128
– Left ankle = 142
– ABI = 1.1
• Abnormal ABI: <0.9
– Left arm = 128
– Left ankle = 108
– ABI = 0.84
Heart Rate Responses During
Exercise and Recovery
• Chronotropic incompetence related to exercise is
associated with increased CV events:
– No beta-blockade taken prior to testing: <85% of age predicted
– Beta-blockade taken prior to testing: <62% of age predicted
• Recovery HR = twofold increased future risk for CV
events and all-cause mortality if:
– Decrease in HR <12/min at 1 min
– Decrease in HR <22/min at 2 min
Seven Elements for Graded Exercise
Testing
•
•
•
•
Pretest considerations
Appearance and quantification of Sx
ECG responses during exercise
Blood pressure responses during exercise
and recovery
• HR responses during exercise and recovery
• Assessment of functional capacity
• Interpretation of findings (six components)
and generation of report
Assessment of Functional Capacity
• Exercise duration
• Estimated METs
• Peak oxygen uptake
– Declines by:
• Healthy, inactive: ~5% to 10% per decade
• Healthy, active: ~3% to 6% per decade
Seven Elements for Graded Exercise
Testing
•
•
•
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Pretest considerations
Appearance and quantification of Sx
ECG responses during exercise
Blood pressure responses during exercise
and recovery
• HR responses during exercise and recovery
• Assessment of functional capacity
• Interpretation of findings (six components)
and generation of report
Interpretation: Six Items to Address
• A. Chest pain. Typical angina, atypical or
noncardiac, none. Note time to onset, test
limiting, time to resolution, therapies
needed to help resolve?
• B. ST segment for myocardial ischemia
diagnosis. Time of onset, magnitude of
change, and time to resolve. Call it positive
or negative or nondiagnostic.
(continued)
Interpretation (continued)
• C. Heart rate response:
– Normal (>85% of age predicted, not on betablockade)
– Chronotropic incompetence (<85% of age predicted,
not on beta-blockade)—associated with increased
future risk for cardiac mortality
– Normal recovery rate: 12 or more in 1 min, 22 or
more in 2 min—associated with increased future risk
for cardiac mortality
• D. Blood pressure response: normal,
hypertensive, hypotensive
(continued)
Interpretation (continued)
• E. Arrhythmia: State findings.
• F. Exercise capacity: State peak metabolic
equivalent (MET) level and compare to
normative data set; state reason for
stopping.
Possible Major Causes for FalsePositive and False-Negative Findings
in an ECG Stress Test
• False positive = positive stress ECG with no
significant coronary disease noted with
coronary angiography
– Female gender, digoxin therapy, LBBB, LVH,
cardiomyopathy
• False negative = negative stress ECG with
significant coronary disease noted with
coronary angiography
– Failure to reach ischemic threshold (insufficient effort),
monitoring of insufficient leads
(continued)
Possible Major Causes for FalsePositive and False-Negative Findings
in an ECG Stress Test (continued)
Cardiac catheterization: gold
standard
ST-segment
change on ECG
Positive
Negative
Positive
True positive
False positive
Negative
False negative
True negative
In Addition to Six Key Elements of Interpretation to
Include in Final Report, Also Consider Including
Estimation of Prognosis Using Duke Score
• Duke score =
Exercise time using Bruce protocol – (5 × ST amount of
depression) – [4 × (angina score of 0, 1, or 2)]
• Where:
– Less than -11 = high risk = >3%/yr mortality
– -10 to 4 = intermediate risk = >1% to 3%/year mortality
– >4 = low risk = <1%/yr mortality
Reasons for Stopping a Stress Test
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Blood pressure >250/120 mmHg
BP drop >10 mmHg below baseline
ST elevation >1 mm
ST depression >2 mm
Serious arrhythmia
Limiting dyspnea or angina (2+)
Achieved 85% to 100% of predicted HR?
Gait
Fatigue
Other
Principles of Prescribing Exercise
• Safety—the primary tenet
• Specificity of training
– Physiologic adaptations are specific to the cardiorespiratory,
neurologic, and muscular responses that are called upon to
perform the exercise
• Progressive overload
– Relationship between magnitude of stimulus or volume of
exercise and benefits gained
• “Floor effect,” threshold level below which few adaptations
occur
• “Ceiling effect,” threshold level above which benefits
plateau or are diminished
Progressive Overload
Intensity / Frequency / Duration
Provide sufficient “overload” stimulus to
improve overall athletic performance
FITT Principle for Cardiorespiratory
Endurance
• F = frequency of exercise (e.g., 5 d/wk)
• I = intensity of exercise
.
– Objective: VO , heart rate, watts
2
• Heart rate–based method, use heart rate reserve (HRR) method
– (HRR × desired percentages) + HRrest = target HR range
– Common percentages used are 60% (0.6) and 80% (0.8)
– Subjective: rating of perceived exertion (e.g., 11-14 on Borg
6-20 scale)
(continued)
FITT Principle for Cardiorespiratory
Endurance (continued)
• T = time or duration (e.g., 30 min/wk)
• T = type or mode of exercise (e.g., walk, bike)
• Diminishing
return
– Concomitant
CV or
orthopedic risk
CV or
orthopedic Risk
– Sigmoidal
shaped
Improvement
• Dose
response
curves for:
Dose
(intensity, duration,
frequency)
FITT Principle for Muscular Strength
or Endurance
• F = frequency of exercise (e.g., 1-3 d/wk)
• I = intensity of exercise
– Objective: 60% to 80% of 1-repetition maximum
– Subjective: rating of perceived exertion
• T = time or duration (e.g., one to three sets
of 8-12 repetitions per set, with 2 min rest in
between sets)
(continued)
FITT Principle for Muscular Strength
or Endurance (continued)
• T = type or mode of exercise; concentric and
eccentric muscle actions involved in
multijoint (e.g., chest shoulders, hips) and
single-joint (e.g., abdominal muscles,
hamstring group, biceps) exercises
General Recommendations for
Resistance Training
• Lift throughout the range of motion unless
otherwise specified.
• Breath out (exhale) during the lifting phase
and in (inhale) during the recovery phase.
• Do not arch the back.
• Do not recover the weight passively by
allowing weights to crash down before
beginning the next lift (i.e., always control the
recovery phase of the lift).
(continued)
General Recommendations for
Resistance Training (continued)
• In certain clinical populations the following
may be prudent:
– Initially monitor blood pressure before and after a
resistance training session and periodically during a
session.
– Try to involve the same clinical exercise professional
who assisted with a patient's initial orientation and
evaluation in regular reevaluations of lifting technique.
– Regularly assess for signs and symptoms of exercise
intolerance that may occur during resistance training.
– Instruct participants to train with a partner.
Quantifying Exercise Dose or Volume
• Allows for a comparison and evaluation of
dose and dose effect across studies using
different frequencies, durations, or intensities
of exercise.
– Kilocalories
– Met-hr/wk or MET-min/wk
• Walking at a moderate pace of ~4 METs for 3
sessions per week for 40 min per session = 480
MET-min/wk or 8 MET-hr/wk
Conclusion
• The GXT is a useful, and often the first,
diagnostic tool used to assess the presence
of significant CAD with or without nuclear
perfusion or echocardiography imaging.
• Data from the test can be used not only to
help diagnose the presence of CAD but also
to determine prognosis and help design an
exercise training program.
(continued)
Conclusion (continued)
• Any type of exercise training routine,
whether it is cardiorespiratory conditioning,
resistance training, or ROM training, should
follow the FITT principle to ensure an
optimal rate of improvement and safety
during training.