Cardiac Stress Testing

1. Cardiac Stress Testing

2. What is a stress test? • A progressive graded test that reproduces diagnostic, prognostic, and functional abnormalities in clients with cardiovascular and pulmonary disorders • Evaluates electrocardiographic, hemodynamic, and symptomatic responses to exercise in a controlled environment • Assesses exercise tolerance and can produce symptoms not present at rest

3. Indications for Cardiac Stress Testing • Diagnosis • Indicated for those with symptoms of CAD • Indicated for those with multiple risk factors • Used in context with other clinical data • Prognosis • Evaluation of those with known or suspected CAD • Predict long-term mortality based on ECG findings at rest, during exercise and in exercise recovery

4. Indications for Stress Testing • Post myocardial infarction • May be done as early as four days post MI • Prognostic assessment • Activity prescription • Functional capacity • Exercise prescription • Activity counselling • Return to work

5. Standardized Stress Testing Protocols • Astrand • Bruce – Protocol used with treadmill stress testing at TBRHSC • Balke • Ellestad • Naughton • Ramp – Protocol used with Cardiopulmonary stress testing at TBRHSC

6. Regular Bruce Protocol Stress Test

7. Modified - Bruce Protocol Stress Test

8. Regular Bruce Protocol Stress Test • Client preparation • No caffeine, tobacco, alcohol at least 24 hours prior to test • May eat a light breakfast • Wear loose comfortable clothing and footwear appropriate for walking on a treadmill

9. Regular Bruce Protocol Stress Test • Instruct client • That they will be walking on a treadmill that will increase in speed and incline at regular intervals • That electrodes be will be applied to the chest wall to monitor heart rate and the heart’s reaction to exercise • A blood pressure cuff will be placed on the arm and blood pressure will be monitored at regular intervals

10. Indications for terminating exercise testing • Absolute indications: • Moderate to severe angina • Near syncope, dizziness, ataxia • Cyanosis or pallor • Sustained ventricular tachycardia • Client’s desire to stop • A >10mmHg systolic blood pressure drop from baseline when accompanied by other signs of ischemia • ST elevation >1mm without diagnostic Q waves

11. Indications for terminating exercise testing • Relative Indications • >10mmHg systolic blood pressure drop from baseline without other indications of ischemia • >2mm downsloping or horizontal ST depression or marked axis shift • Arrhythmias other than sustained VT such as bradyarrhythmias, heart block, supraventricular tachycardia, multifocal VPB’s or triplets of VPB’s • Wheezing, leg cramps, SOB, fatigue increasing chest pain • Hypertension >250mmHg systolic, >115mmHg diastolic

12. Negative test • Heart rate increases linearly with exercise • Systolic blood pressure increases with exercise • Diastolic blood pressure stays the same or increases or decreases by about 10mmHg • No symptoms of chest discomfort are produced • No horizontal or downsloping ST depression • Test result could be false-negative if the plaque is an atheromata (inside the wall) or if the plaque that is protruding into the lumen is less than 75%

13. Positive stress test • Horizontal or downsloping ST depression >1mm (indicative of ischemia) • Limiting symptoms of chest discomfort are produced • A false-positive stress test could be the result of a serum electrolyte imbalance, left ventricular hypertrophy, medications such as digoxin, mitral valve prolapse

14. Cardiopulmonary Stress Testing • Indications for CPX • Diagnose pulmonary disease • Test modality – cycle ergometry • Expired gasses are directly measured • Ramp protocol – speed and resistance increased at one minute intervals • Same preparation as for regular stress testing