EXERCISE STRESS TESTING Flashcards
What is the purpose of exercise stress testing (EST)?
To diagnose myocardial ischemia, estimate prognosis, evaluate therapy outcomes, and assess cardiopulmonary reserve
EST uses exercise as physiological stress to detect cardiac abnormalities not present at rest.
What methods can patients use to exercise during stress testing?
Treadmill, bicycle ergometer, or arm ergometer
Treadmills are more commonly used in the U.S. for EST.
What is the difference between maximal and submaximal exercise stress tests?
- Maximal EST aims for the highest exercise workload tolerated by the patient
- Submaximal EST has lower targets, often used after myocardial infarction
Maximal EST is terminated based on symptoms or abnormal responses.
What is the mean sensitivity and specificity of exercise stress testing for coronary artery disease?
Mean sensitivity is 68% and mean specificity is 77%
Sensitivity increases for multivessel disease and left main disease.
What are the risks associated with exercise stress testing?
Morbidity less than 0.05% and mortality less than 0.01% in the general population
Slightly increased mortality and morbidity observed in patients post-myocardial infarction.
What are common indications for exercise stress testing?
- Diagnosing suspected obstructive CAD
- Risk stratification in patients with known CAD
- Evaluating patients with significant clinical status changes
Other indications include post-myocardial infarction assessments and evaluating vasospastic angina.
Should asymptomatic patients undergo exercise stress tests?
Generally discouraged due to low pretest probability of CAD
Selected asymptomatic patients may be considered for EST under specific clinical circumstances.
What parameters are monitored during an exercise stress test?
- Clinical response to exercise
- Hemodynamic response
- ECG changes during exercise
Monitoring includes symptoms, heart rate, and blood pressure response.
What is an adequate heart rate to elicit an ischemic response during EST?
85% of the maximal predicted heart rate
Achieving only 70% reduces stress-related myocardial perfusion defects significantly.
How is the maximal predicted heart rate calculated?
Maximal predicted heart rate = 220 - age
What is the Borg scale?
A numeric scale of perceived exertion used during EST
Values reflect levels of work, with 14 to 16 indicating anaerobic threshold.
What defines a metabolic equivalent (MET)?
Caloric consumption compared to resting metabolic rate; 1 MET = 1 kilocalorie per kg per hour
Activities of 2 to 4 METs are considered light.
What is considered a hypertensive response to exercise?
Systolic BP > 250 mm Hg or diastolic BP > 115 mm Hg
This response is a relative indication to terminate EST.
Can exercise stress tests be ordered for patients taking beta-blockers?
Yes, but diagnostic value may be reduced due to inadequate heart rate response
Stopping beta-blockers before EST is discouraged.
What baseline ECG findings interfere with EST interpretation?
- Left bundle branch block
- Ventricular pacing
- > 1-mm baseline ST depression
These conditions may require alternative diagnostic modalities.
When can an exercise stress test be performed after an acute myocardial infarction?
Submaximal EST may be performed as early as 4 days after MI
Later symptom-limited tests can be conducted 3-6 weeks after the event.
How do sex and age affect exercise stress testing results?
- Women have more false-positive results than men
- Age is not a significant factor if the patient can complete the exercise protocol
Both factors should be considered in the context of diagnostic accuracy.
What are robust predictors of cardiovascular events?
Independent of the ECG findings
These predictors help in assessing the risk of cardiovascular events in patients.
What diagnostic modalities should be considered for women with abnormal baseline ECG or poor exercise tolerance?
Coronary CTA, nuclear imaging, echocardiography pharmacological stress test
These modalities can provide additional information beyond standard exercise stress testing.
What was the outcome of the randomized study comparing EST alone with EST with imaging?
No difference in cardiovascular events after 2 years and 48% cost savings compared with imaging EST
This indicates that exercise stress testing alone may be sufficient in certain cases.
Is age an important consideration for exercise stress testing (EST)?
No, if the patient is fit to complete an exercise protocol adequately
Fitness level is more critical than age in determining the appropriateness of EST.
When is an exercise stress test interpreted as positive?
ECG changes of ≥1 mm ST-segment depression or elevation at least 60 to 80 milliseconds after the end of the QRS complex
Also, the occurrence of angina and abnormalities in exercise capacity are considered.
What are the absolute indications to terminate an exercise stress test?
- Drop of more than 10 mm Hg in systolic blood pressure
- ST elevation of more than 1 mm
- Moderate to severe angina
- Neurological symptoms
- Signs of poor tissue perfusion
- Sustained ventricular tachycardia
- Patient request to stop the test
These criteria are based on ACC/AHA guidelines.
What is a cardiopulmonary exercise stress test?
A test monitoring ventilatory gas exchange during exercise to differentiate cardiac versus pulmonary causes of dyspnea
It is also used for follow-up in heart failure or transplant candidates.
