EXPH 3180: Aerobic Clinical Exercise Testing and Prescription

Clinical Exercise Testing purpose

to observe physiological responses to increasing or sustained metabolic demand

-GXT/CPX typically continues until a sign or symptom-limited maximal level of exertion is reached

Indications for clinical exercise test

-DIAGNOSIS (ex: presence of disease or abnormal physiologic response)

-PROGNOSIS (ex: risk for adverse event)

-EVALUATION of physiologic response ( BP and peak exercise capacity)

What is the most common diagnostic indicartion for a clinical exercise test?

the assessment of symptoms suggestive of ischemic heart disease (IHD)

What should be considered when conducting the clinical exercise test? 

-contraindications

-exercise test protocol and mode

-test endpoint indicators

-safety

-medications

-staff and facility emergency preparedness

Exercise Test Supervision

shifted to nonphysician health professionals 

-clinical exercise physiologists, nurses, PTs, PAs

What is conveinent about standardized exercise testing protocols

they are repeatable, yet individualized based on age, exercise tolerance, or symptoms

Exercise test: Monitored Variables and Test Termination

HR, ECG, cardiac rhythm, BP, RPE

-clinical symptoms of myocardial ischemia, inadequate blood perfusion, gas diffusion, and limitations in pulmonary ventilation

-O2 saturation

What is the most accurate measure of exercise capacity?

VO2

When the goal is a symptom-limited (symptom reproduction) test, what should not be used as a reason to end the test? 

a predetermined termination criteria 

Exercise Test: postexercise

low intensity active recovery is often practiced in order to support venous return and hemodynamic stability

What should be considered during interpretation of the clinical exercise test?

-Individual Symptoms

-ECG

-Exercise capacity

-Hemodynamic Responses

-combination of other responses

B adrenergic Blocking agent

lowers/blunts HR response during exercise

HRmax

decreases with age

-attenuated in individuals on B blockers

-large interindividual variability with standard deviations of 10BPM or more

HR Response in exercise

failure to achieve age-predicted HR max >85% in the presence of a maximal effort is an indicator of chronotropic incompetence and is assoc. with increased risk of morbidity and mortality

HR Response in recovery

failure to decrease by >12 BPM during the first minute or >22 BPM by the end of the second minute of active postexercise recovery is assoc. with an increased risk of mortality in individuals diagnosed with or at increased risk for IHD

Interpretation: BP

systolic BP should increase

-normal systolic BP response to exercise is a rate of ~10mmHG per MET

**diastolic will likely only decrease slightly if at all

What does a drop in BP indicate

potential obstruction to flow

Potential SBP responses

-hypotension (with symptoms like dizziness)

-hypertension

-blunted response

-postexercise response

What are common concerns with EKGs

-Arrhythmias

-ST segment abnormalities

Arrhythmias

unexpected rhythm

(not necessarily bad or good)

ST segment abnormality

largest clinical feature of CAD

-elevation indicares an active MI 

-depression indicates the coronaries are lacking O2

What is high exercise capacity indicative of?

high cardiac outpit, suggests the absence of serious limitations of left ventricular function

What is an issue relative of exercise capacity

the imprecision of estimating exercise capacity from exercise time or peak workload

What are advantages of using VO2 measurements

more accurate measurement of exercise capacity

-data may be particularly useful in defining prognosis and the timing of cardiac transplantation and other advanced therapies in heart failure patients

-helpful in differential diagnosis of individuals with suspected CV or respiratory disease

When testing is for EVALUATION, what should be encouraged

exercise to their maximal level of exertion or until a clinical indication to stop is observed

What are some criteria that have been used to confirm whether or not a maximal effort has been elicited

-plateau in VO2 peak

-failure of HR to increase with increases in workload

-postexercise venous lactate concentration >8mmolL

-RPE at peak exercise >17 or >7 (0-10 scale)

-Peak RER >1.10

What are the factors that determine the diagnostic value of exercise testing

the sensitivity, specificity, and predictive value of the test and procedure and prevalence of IHD in the population tested

Sensitivity

the ability to positively identify individuals who truly have IHD

Treadmill GXT has high _______

sensitivity

Specificity

the ability to correctly identify individuals who do not have IHD

Treadmill test does not have high _____

specificity

When you use the Duke Nomogram, what are you assuming? 

maximal exercise test

What can be coupled with Exercise testing with resting ECG is abnormal

Myocardial perfusion imaging, Echocardiogram

Field Walking Test

-non lab based, frequently used in patients with chronic disease

-considered submaximal

-used to evaluate exercise capacity, estimate prognosis, evaluate treatment response

Types of Field Walking tests

-6MWT

-Incremental

-Endurance shuttle test