EXERCISE STRESS TEST
Indication
Contraindication
Preparation
Cardiovascular Risk Factors
• Non-modifiable
– Age
– Gender
– Family History
• Modifiable
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Hypertension
Smoking
Diabetes
Hyperlipidemia
Sedentary life style
obesity
Exercise Stress Testing
• Pathophysiology:
– At rest, there may be adequate coronary blood
flow, with exercise, supply may not keep up with
demand leading to characteristic ST segment
changes and other end points due to obstruction.
– At least a 70-80%occlucions is needed before
coronary stenosis (obstruction) is reliably detected
by this test.
– Significant coronary artery disease can exist with a
negative Exercise Stress Test.
Indications for Stress Testing
1. Evaluation of patients with suspected
coronary artery disease (CAD).
2. Evaluation of patients with known coronary
artery disease (CAD).
1. After myocardial infarction
2. After intervention
3. Evaluation of exercise capacity
Preparation for Stress Testing
• History
• Physical Examination
• Laboratory Studies
– Screening chemistry and hematologic profiles
– Resting ECG
– Medications
– General Activity level
Contraindications to Stress Testing
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Acute myocardial infarction
unstable angina
Acute cardiac inflammation( myocarditis)
Severe congestive heart failure(CHF)
Severe hypertension (>200/>100)
Poor candidate for exercise
Extreme obesity, usually can’t do over 175 KG.
Severe physical disabilities
Severe mental disabilities
Possible Contraindications to Stress Testing
based on Resting ECG
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ST-segment depression or elevation
Ventricular hypertrophy
T-wave inversions
Left bundle branch block
Right bundle branch block
Prolonged QT interval
Equipment for Stress
Testing
 Treadmill or bicycle
or steps
 ECG machine
 Blood Pressure Cuff
 Statoscope
Normal Response to Stress Testing
1)
2)
3)
4)
5)
Heart rate increases
Blood pressure increases
Cardiac output increases
Total peripheral resistance decrease
Oxygen consumption increases
(1MET = 3.5 ml O2/Kg./min =
1 metabolic equivalent)
Abnormal Response to Stress Testing
1)
2)
3)
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6)
Heart rate fails to rise above 120
Blood pressure shows a drop in systolic
Patient physically unable to complete test
Marked hypertension, >260/115
Chest Pain
unusual shortness of breath
Normal ECG Response to Stress Testing
1) ECG Changes
1) QRS complex decreases in size
2) ST segment returns to baseline by 80 millisecond
3) R amplitude may decrease at rates
4) T wave decreases
Abnormal ECG Response to Stress Testing
 ECG Changes
 down sloping ST segments
 ST segment depressed or elevated
 ST segment does not return to baseline by 80
milliseconds
 T wave inversion
Protocols
• Work load is expressed in METS (1 MET = 3.5ml O2
/Kg/min).
– 1 MET (3.5 ml) = basal O2 requirement
– 5 METS (17.5 ml) = activities of daily life
– 13 METS (45.5 ml) = good work out and excellent
prognosis.
• Men: Predicted METs = 14.7 − 0.11 × age
• Women: Predicted METs = 14.7 – 0.13 × age
• Classify functional capacity below normal if
lower than 85% of the predicted value
Reasons to Terminate Test
• Absolute
– Patient requests to stop
– Technical/mechanical
difficulties
– Suspected MI
– CNS symptoms
– Serious dysrhythmias
– Drop in systolic BP
– Severe Angina
– ST elevation > 1mm
• Relative
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> 2mm of ST depression
Increasing chest pain
Tired or SOB
Wheezing
Claudication
SBP>260, DBP>115