Chapter 5: Graded Exercise Testing and Exercise Prescription
Target Heart Rate Equation
(intensity fraction) (HR max - HR rest) + HR rest
Target VO2 (VO2 Reserve Method0 Equation
(intensity fraction)(VO2max - VO2rest) + VO2rest
What does specificity to a test mean?
- "True negative" - Measurement proportion of negatives which are correct in identifying someone does not have the condition - Correct in identifying no disease
What does sensitivity to a test mean?
- "True positive" - Measurement proportion of actual positive tests which are actually positive - Correct in diagnosing
What are the indications primarily used for?
- Assess chest pain and like symptoms to assist in the diagnosis of coronary artery disease (CAD) - Assess blood flow to the myocardium (myocardial ischemia) - Test usefulness is greatest among those with an intermediate (not low and not high) pretest likelihood of having heart disease - Most useful for those with intermediate probability of CAD
What are six items to address in a GXT?
- Chest pain - ST segment for myocardial ischemia diagnosis - HR response - BP Response -Arrhythmia - Exercise capacity
What are the pretest instructions for subject preparation?
- 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
Besides what the primary use for indications, what else are they used for?
- Determine long-term prognosis + Duke Treadmill Score (DTS), peak MET level, symptom limited test - Assess therapeutic interventions - Assess pre/post surgical interventions (pacemaker, pre-op preparation) - Assess functional capacity in order to determine appropriate and safe exercise prescription or occupational clearance
What are some indications for GXT?
- Evaluate the effectiveness of therapies (drugs, exercise, etc). - Evaluate changes to hemodynamics in people with high blood pressure, dysrhythmias, syncope, or chest pain. - Surgical clearance - Used annually to track changes*.
What does a hypotensive response indicate during exercise?
- Evidence of ischemia -Decrease below resting SBP
What does the information gained from GXT provide?
- Info from GXT will be used to determine activity duration and intensity (METs) at which angina occurs as to avoid in the future - Ischemic threshold (MET level, HR, BP, time)
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
How should heart rate response be addressed?
- Normal (>85% of age predicted, not on beta-blockade) - Chronotropic incompetence (<85% of age predicted, <62% on beta blocker)—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
What is high risk criteria for GXT?
- One or more signs or symptoms of CV, pulmonary, or metabolic disease - Established CV, pulmonary, or metabolic disease
When selecting a protocol and modality, what are examples to taking into consideration the characteristics of the patients?
- Orthopedic/Gait capabilities - Functional capacity - Occupational concerns - Athlete specificity
What are some things to monitor in ECG responses during exercise?
- Rate - Amplitude of waves - Conduction velocity - Arrhythmias
What are types of stress tests?
- Stress ECG only -Stress ECG with imaging -Pharmacologic stress with imaging (echo or cardiac perfusion imaging)
What are examples of modality?
- Treadmill - Cycle ergometer -Arm Ergometer
What are things to assess at the end of each stage?
- patient's rating of perceived exertion (1-10 OR 6-20) - clinical symptoms (Excessive dyspnea (>2) and Claudication (>2))
What is the criteria for a positive test for myocardial ischemia?
1 or more mm of horizontal or downsloping ST depression or 1.5 or more mm of upsloping ST depression.
What are some advantages to using a treadmill for a GXT?
1. Appropriate for all healthy people (not limited by lower body disability). 2. Gives best value for maximal aerobic capacity. 3. Many protocols to choose from. - Increase speed and grade - Increase grade and not speed - Increase speed and not grade
What are the seven elements for graded exercise testing?
1. Pretest considerations 2. Appearance and quantification of symptoms 3. ECG responses during exercise 4. 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. Look for contraindications. 4. Pretest instructions and subject preparation for ECG - Explained days prior to test (Food consumption, OTC use, clothing) - Immediately before (Testing procedure, reassure patient, encourage questions) 5. Selection of exercise protocol and modality
What does a hyper tensive response indicate during exercise?
>210 mmHg at peak - Two to three fold increased future risk for developing HTN at rest - Abnormal recovery SBP response: 3 minutes of recovery should allow a >10% decrease from peak SBP
Arrhythmias
A condition in which the heart beats with an irregular or abnormal rhythm.
What are advantages and disadvantages to arm ergometer?
Advantage: Appropriate for people who cannot use lower limbs (neurologic, orthopedic, or vascular conditions). Disadvantage: Less sensitive to detection of cardiovascular disease compared to treadmill.
What are advantages and disadvantages to using a cycle ergometer?
Advantage: Good for people who have trouble walking (frail, poor eyesight, dizziness, obesity) Disadvantage: Lower VO2max values compared to treadmill
What are positive risk factor examples?
Age Family history Cigarette smoking Sedentary lifestyle Obesity Hypertension Dyslipidemia Pre diabetes
P Wave
Atrial depolarization
What are some reasons for stopping a stress test?
Blood pressure >250/115 mmHg BP drop >10 mmHg below baseline ST elevation >1 mm ST depression >2 mm Serious arrhythmia Limiting dyspnea, angina, or claudication (2+) Achieved 85% to 100% of predicted HR? Gait Fatigue Other
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
PR Interval
Delay of impulse at AV node
ST Segment
Early ventricular repolarization
Duke Score Score
Exercise time using Bruce protocol - (5 × amount of ST depression) - [4 × (angina score of 0, 1, or 2)]
FITT
Frequency, Intensity, Time, Type
What are negative risk factor examples?
High density lipoprotein (HDL) cholesterol
What are the types of stress ECG with imagining and what do they assess?
I. ECG plus echocardiogram (stress echo) - Allows for assessment of wall motion abnormalities - Cardiac sonography II. ECG with radionuclide imaging (stress nuclear) - Allows for assessment of distribution of blood flow - Cardiac perfusion imaging
How long should the protocol take? What would cause termination of the protocol?
Last 8-12 minutes 2-3 minute stages with increasing intensity (increase 1-3 METs/stage) Termination of test should be limited by the cardiorespiratory system(s) and not by skeletal muscle fatigue.
What are the estimations of prognosis using the Duke Treadmill Score (DTS)?
Less than -11 = high risk, 35% 5 year mortality -10 to 4 = intermediate risk, 10% year mortality >4 = low risk, 3% 5 year mortality
What does a positive test for myocardial ischemia indicate?
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
What is low risk criteria for GXT?
Men <45, <2 CV RF Women <55, <2 CV RF
What is moderate risk criteria for GXT?
Men ≥45, 2 CV RF Women ≥55, ≥ 2 CV RF
Bruce Protocol
Multistage treadmill protocol that increases the workload by changing both the speed and grade
What does a false negative finding in an ECG stress imply?
Negative stress ECG with actual significant coronary disease noted with coronary angiography (Failure to reach ischemic threshold [insufficient effort], monitoring of insufficient leads)
How should blood pressure response be addressed?
Normal, hypertensive, hypotensive
What is considered normal and ischemia evidence in the amplitude of waves in an ECG response during exercise?
Normal: Decrease in total QRS amplitude Ischemia: Increase in QRS amplitude
What is considered normal evidence in the conduction velocity in an ECG response during exercise?
PR and QRS durations shorten due to catecholamine-induced increase in conduction velocity
What does a false positive finding in an ECG stress test imply?
Positive stress ECG with no significant coronary disease noted with coronary angiography (Higher occurrence in females and those with LBB or LVH)
What is monitored when testing for myocardial ischemia?
ST segment changes
How should exercise capacity be addressed?
State peak metabolic equivalent (MET) level and compare to normative data set; state reason for stopping.
Functional Capacity
The maximum physical performance represented by maximal oxygen consumption
Why learn about graded exercise testing (GXTs)?
The same principles and elements are used in conjunction with many similar and more complex diagnostic and prognostic procedures such as: Stress ECG only GXT with EKG and gas exchange measurement Exercise stress echocardiogram Exercise stress nuclear test or myocardial perfusion imaging (MPI) Pharmacologic stress
What does the general interview and examination include?
This includes determining risk factors and medicine reconciliation
How should ST segment for myocardial ischemia diagnosis be addressed?
Time of onset, magnitude of change, and time to resolve. Call it positive, negative, or non-diagnostic.
How should chest pain be addressed?
Typical angina, atypical or non-cardiac, none. Note time to onset, test limiting, time to resolution, therapies needed to help resolve?
How is function capacity (FC) useful?
Useful gauge to evaluate disease progression, exercise training program, and medication
QRS Complex
Ventricular depolarization
T Wave
Ventricular repolarization