CET+and+Interp+ C5 6

8/13/2019 CET+and+Interp+ C5 6

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Clinical Exercise Testing-

ApplicationsPre-discharge/post MI, PTCA, CABGFunctionalDisease progressionDisability/Return to WorkDiagnostic (usually Bruce TM test)

chest paindyspneasyncope/dizziness


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Diagnostic Testing-Measurements

HR (85% PMHR) & BpSigns and symptoms

EKG (ectopic beats and ST segment changes)

1mm @ .08 sec = significant ST segment

depression = ischemia


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ST-T wave segment changes

ST depression

ST elevation

T wave inversion

Ischemia


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ST segment slope

Upslope less suggestive

Flat more suggestive

Downslope most suggestive

Magnitude of ischemia


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ST Segment Depression


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Magnitude of ischemia is

directly proportional to:ST segment slope

# of EKG leads involvedPersistence of ST-T wave changes duringrecoveryAmount of ST depression (1mm vs. 5)


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Sensitivity/Specificity

Sensitivity -% of patients tested who haveCAD and an abnormal test (ST chgs.)

TPR=70% ; FPR30%

Specificity -% of patients w/o CAD who will

have a negative testTNR=80% ; FNR=20%


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False Positive Rate=30% / Factorscontributing to FPR

Female gender (Thallium GXT)

Resting ECG changes (LVH)

Some meds (digitalis)


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Magnitude of ischemia isinversely proportional to:

Double product (rate pressure product) SBP xHRMaximal HR achievedSBPOxygen uptake achieved


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Test Modalities

CycleTM

Arm ergometer

advantages/disadvantages


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Testing Protocols-Fig. 5.3

TMBruce/Modified Bruce

Balke-WareUSAFSAMNaughton/Modified Naughton

CycleYMCAPWC-170


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Treadmill TestingBruce Treadmill Test Stages

Stage 1 = 1.7 mph at 10% GradeStage 2 = 2.5 mph at 12% GradeStage 3 = 3.4 mph at 14% GradeStage 4 = 4.2 mph at 16% GradeStage 5 = 5.0 mph at 18% GradeStage 6 = 5.5 mph at 20% GradeStage 7 = 6.0 mph at 22% GradeStage 8 = 6.5 mph at 24% GradeStage 9 = 7.0 mph at 26% Grade

The Bruce Protocol Formula for Estimating VO2 Max

For Men VO2 max = 14.8 - (1.379 x T) +(0.451 x T) - (0.012 x T)For Women VO2 max = 4.38 x T - 3.9T = Total time on the treadmill measured as a fraction of aminute (i.e.: A test time of 9 minutes 30 seconds would be

written as T=9.5).


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VO2 MaxNorms for

Men -Measured

inml/kg/min

Age Very Poor Poor Fair Good Excellent Superior

13-19 55.9

20-29 52.4

30-39 49.440-49 48.0

50-59 45.3

60+ 44.2

Bruce Norms


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VO2 Maxvalues forWomen asmeasured

in

ml/kg/minAge Very Poor Poor Fair Good Excellent Superior13-19 41.920-29 41.030-39 40.0

40-49 36.950-59 35.760+ 31.4

Bruce Norms


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Functional Aerobic Impairment(FAI)

% FAI = predicted VO2 measured VO2 x 100

predicted VO2

Predicted (male): 57.8 (.445 x age)

Measured: 14.8 - (1.379 x T) + (0.451 x T) -(0.012 x T)


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Example-FAI

50 y/o male

Predicted Vo2 = 57.8 (.445 x 50) = 35.5 ml/kg/min

Measured VO2 = 20.2 ml/kg/min (TM time)

35.5 20.2

FAI = ______________ x 100 = 43%35.5

FAC = 57%


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Protocols cont.

Step wise vs. rampIncrements 8-12 mins

HR, BP & ECG monitored pre-post exercise(6-8 mins or until any changes return to baseline(Table 5.2)RPE, angina scale & claudication scales(Fig.5.4)


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Indications for stopping a test(Box 5.2) Absolute/Relative

Drop in SBP (>10 mmHg) with other signs ifischemia?Mod-severe angina (3 on standard scale)Sustained ventricular tachycardiaST elevation (1.0 mm)Excessive ST depression (>2mm horizontal ordownsloping)arrhythmias


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Gas exchange and ventilatorymeasurements: CP-GXT

Utility:Accuracy of VO2 measurement

Distinguish b/w cardiac and pulmonary limitations(dyspnea)Additional assessments of cardiac function (O2pulse; VTh)Rule out malingering (RER)


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Critical Measurements:

HR, Bp, EKG and signs/symptomsVO2 measured vs. estimated (obesity; lungdisease)

VE airflow limitation? (VE/MVV)RER effortVTh cardiac function

VE/VO2 ; VE/VCO2 ventilating efficiencySaO2 or PaO2 gas exchange limitation?O2 pulse VO2/HR (indirect indicator of SV)


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Thallium 201 Stress Test

(or Technetium99

)


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Thallium Scan


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Echocardiography (Ultrasound)

Transesophageal echocardiogram. Doppler echocardiogram. Stress echocardiogram.

Mitral valveprolapseLVH


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Pharmacological Stress Testing

Dobutamine stress echo detection of wallmotion abnormalities (+ chronotropic agent)

Dipyridamole (persantine) or adenosine vasodilators used to assess coronaryperfusion in conjunction with a nuclearimaging agent (increased blood flow innormal CA; steals blood flow from stenoticvessels)Accuracy = ~86%


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Considerations for PulmonaryPatients-Essential Measurements

Spirometry (FVC, FEV1, MVV, TLC)VE (VE/MVV) -calculation of breathing reserve

airflow limitation SaO2/PaO2 oxygenation gas exchangelimitation; ABG or pulse oximetry

VO2/VCO2 (direct measurements)VT and Fb


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Asthma and Exercise-InducedAsthma (EIA)

Incidence 20 million; by ~5% per year80% of asthmatics have EIA (EIB)

Only 5-15% of non asthmatics have EIAHigh incidence in winter sport athletes (40-50%)

Mechanism : loss of H2O and airway drying histamine from mast cells bronchoconstriction and inflammation


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Asmogenic Agents/Symptoms

Allergensanimal dander, dust mites, pollen

Irritantssmoke, air pollution, cold air, sulfites (wine),chlorine?

Exercise (especially in cold air)

Symptoms

cough, wheeze, dyspnea, chest tightness


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Testing Protocols for EIA(bronchial provocation test)

85% PMHR ( VE)

6-8 mins durationFEV1 measured before and at 5 min intervalsafter exercise

15 % drop in FEV1 = EIA

f


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Testing for PVDAnkle-brachial index (ABI)

Arterial pedal pulses dopplertibialis anteriorposterior pedal

Normal value > .90Example:At rest: ankle = 110 ; brachial = 120 110/120 = .91Moderate-to-Severe Occlusion (post-exercise)ankle = 70; brachial = 140 70/140 = .50

CET+and+Interp+ C5 6

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