Section II

Pre-Participation CV Screening and Clinical Exercise Testing

Pre-Participation CV Screening

Purpose of pre-participation screening Components of screening

CH 2 Guidelines PAR-Q Signs and symptoms of CHD – Table 2-1 Risk Factors – Table 2-2 Initial Risk Stratification – Table 2-3

ACSM Guidelines for Screening Table 2-7

Pre-Participation CV Screening

State of the Practice KJM research paper

New AHA/ACSM position paper AHA website

General Purposes of Exercise Testing (ETT or GXT)(CH5 ACSM Guidelines)

**Evaluate Exercise Capacity** Evaluate functional capacity

VO2 max

Symptom-limited VO2 (SL-VO2)

Peak VO2

Evaluate fitness Pre-post exercise training program

**EXERCISE TEST FOR DIAGNOSIS OF CAD**

Principle of diagnostic ETT: Ischemic responses such as ST segment

depression and angina indicate the presence of CAD.

Example

Rest Absence of symptoms Normal ECG

During Exercise Symptoms ST depression

Exercise tests used to evaluate patients with a history of chest pain

Typical CP of probable ischemic origin

Atypical Cp of probable non-ischemic origin

Recurrent or worsening angina

Evaluate other symptoms

Dyspnea (shortness of breath)

Syncope (dizziness)

Unusual fatigue

**ESTIMATE PROGNOSIS AND SEVERITY OF CAD**

Abnormal test results can give an indication of severity of disease (bot not the location of stenosis)

More severe CAD --- poorer long-term prognosis

ETT Findings Indicating Poorer Prognosis

Limited exercise capacity

Exercise induced hypotension (EIH)

Marked ST depression

Angina with any of the above

**EVALUATE ARRHYTHMIAS**

Detection of arrhythmias

Assessment of anti-arrhythmia therapy

**EVALUATION OF THERAPEUTIC INTERVENTIONS**

Pre-post CABG or PTCA to evaluate “revascularization”

Evaluation of medical therapy

**BASIS FOR EXERCISE PRESCRIPTION***

Determine maximal (peak) heart rate

Determine exercise tolerance

Determine ischemic threshold

**POST-MI EVALUATIONS**

Pre-discharge activity guidelines

Evaluate prognosis

MEASUREMENTS DURING THE EET

1. ECG Continuous (oscilloscope) Intervals (each stage of graded test)

MEASUREMENTS DURING THE EET

2. Heart Rate Each stage Peak exercise Calculate % age predicted maximal

heart rate (APMHR) achieved HR achieved during test / predicted

maximal heart rate (using 220-age) x 100

MEASUREMENTS DURING THE EET

3. Blood Pressure Each stage Peak exercise Recovery Evaluate normal/abnormal response to

exercise

MEASUREMENTS DURING THE EET

4. Symptoms and exertion Angina(1-4 scale) RPE Shortness of breath (SOB) Dizziness Other

MEASUREMENTS DURING THE EET

5. Exercise Duration Use to estimate VO2 max

Sequence for measurements during the EET – Guidelines Table 5-1 pg. 95

ETT TERMINATION POINTS

ACSM Guidelines – Table 5-4 pg. 97

INTERPRETATION OF DIAGNOSTIC EXERCISE TEST

CH 6 ACSM GUIDELINESCH 28 RESOURCE MANUAL

DIAGNOSTIC TESTS

Positive exercise test *ST segment depression and/or angina

Negative exercise test (“Normal”) for ischemic changes

DIAGNOSTIC TESTS

Non-Diagnostic, indeterminate, or inconclusive test results Dependent upon APMHR achieved

Negative exercise test for angina and ischemic ST segment changes at an inadequate peak heart rate

Results of the test can not be used to “rule out” CAD

(+) TEST RESULTSMARKEDLY (+) and BORDERLINE (+)

Severity of ECG changes Presence and severity of angina Early onset of ischemic changes Normal BP vs. exercise hypotension

SENSITIVITY AND SPECIFICITY

Terms used to describe how reliable a test distinguishes diseased from non-diseased states.

Guidelines Table 6-16 pg. 140

Sensitivity: A measure of the test’s ability to give a positive (+) result when the subject does have disease.

Specificity: A measure of the test’s ability to give a (-) result when the subject does not have disease.

“Positive” and “Negative” exercise test results can be compared to angiographic findings:

True Positive (TP): ( ) ETT and ( ) angiogram

True Negative (TN): ( ) ETT and ( ) angiogram

False Positive (FP): ( ) ETT and ( ) angiogram

False Negative (FN): ( ) ETT and ( ) angiogram

Sensitivity: TP / TP X FN X 100

Specificity: TN / TN X FP X 100

Some possible reasons for low Specificity [=high FP]: table 6-18

1. LOW pre-test likelihood of disease Example: women; young age; low risk

factor profile; asymptomatic

2. Abnormal resting ECG Example: ST changes at rest

3. Medications which affect the ECG Example: digitalis

4. Normal variant Example: ECG has ST segments that

look like ischemic ST depression

Some possible reasons for low Sensitivity: [high FN] table 6-17

1. Inadequate leads monitored

2. Canceling vectors

3. Single vessel disease

Collaterals during exercise

PREDICTIVE VALUE OF ETT RESULTS

1. Prevalence of disease in the population tested (“Baye’s Theorem”) influences predictive value of ETT results The pre-test likelihood of disease

influences the post-test probability of having the disease

Example: (+) ETT: 50 y/o male; HTN;

hypercholesterolemia; Hx CP with exertion

(+) ETT: 25 y/o female; normal BP; (-) RF’s; asymptomatic

PREDICTIVE VALUE OF ETT RESULTS

2. Exercise test results influence predictive value

Example: Drastically (+): early onset of ischemic

changes (low workrate and low heart rate) and/or marked ST depression and angina

Severity of ECG changes (ST depression)

Amplitude Example:

• 1mm = borderline• 2mm = moderate• >2mm = severe

Slope Unsloping Horizontal Downsloping

EXERCISE TESTING MODALITIES and PROTOCOLS

Numerous exercise modalities Treadmill Cycle ergometer Steps Field tests

Numerous protocols Varying MET increments

“Graded Protocols”

Vary speed (mph) of walking & grade (% inclination) in stages (usually 2-3 min)

Commonly used treadmill protocols:

(standard) Bruce Modified Bruce Balke Naughton Modified Astrand Ramp protocols Ellestad Individualized Ramp tests

General characteristics of treadmill protocols:

Continuous Multistage (“graded”) Start low MET level (2-3 METS) Increase workrate 1-3 METS/stage Last between 6-15 minutes Use large muscle groups Do not require significant skill

Testing protocol should be appropriate for the person being tested

Example: athlete vs. early post-MI

TREADMILL PROTOCOLS

Standard Bruce – diverse Modified Bruce – low-moderate exercise

tolerance and/or difficulty with gait Balke – avg. to above avg. fitness levels Naughton – severely limited exercise

tolerance RAMP – low level to athletic protocols

CYCLE VS. TREADMILL EXERCISE TESTS

1. ADVANTAGES OF CYCLE:

Portable Quiet and less upper extremity

movement Easier to assess BP ECG may show less artifact Important for persons with difficulty

with gait

2. DISADVANTAGES OF CYCLE

Underestimate VO2 max and HR max

(a) Unfamiliarity with cycling

(b) smaller muscle mass

3. SENSITIVITY TO DETECT CAD

No significant difference

MAXIMAL EXERCISE TESTS

PREDICTION EQUATIONS USED FOR THE ESTIMATION OF VO2 MAX

Estimation of VO2 max based on actual (direct) measures of VO2

Physiologic Principle of Estimating VO2 max: VO2 is directly related to workrate,

therefore, estimations of VO2 max can be made on standardized tests by determining the highest workrate that can be achieved and calculating the energy cost of that power output.

Estimation can result in large potential errors:

Non-Standardization Hand held exercise vs. non-hand held Population specific equations Inappropriate test endpoints Familiarization

Protocol specific equations:

EXAMPLE: Bruce treadmill: Males: VO2 max = 3.88 + [.056 x (time-

sec)] Female: VO2 max = 1.26 + [.056 x

(time-sec)]