Week 2: clinical exercise testing - CVD Flashcards
What are the absolute contraindications for conducting a Clinical Exercise Test (CET) in patients with cardiovascular disease?
Absolute contraindications include:
-Acute MI less than 48 hours old
- Unstable angina
- Uncontrolled symptomatic heart failure
- Acute myocarditis or pericarditis
- Uncontrolled cardiac arrhythmias with decreased cardiac output
- Severe aortic stenosis
- Dissecting aneurysm
- Acute pulmonary embolus (PE)
- Recent changes to the resting ECG indicative of ischemia or infarction
Explain the clinical implications of achieving less than 50% of the predicted HRmax during a CET.
Achieving less than 50% of the predicted HRmax may be due to factors such as beta-blocker medication use, symptom limitation, or motivational issues. It indicates that safety has only been established up to that point, and further assessment is needed to determine exercise tolerance and capacity accurately.
Describe how exercise-induced ischemia can be identified during a stress test.
Exercise-induced ischemia can be identified by observing ST-segment depression or elevation on the ECG during exercise, indicating reduced blood flow to the myocardium. Symptoms such as chest pain, dizziness, or significant BP changes may also accompany these ECG findings.
What is the primary purpose of the Bruce Protocol in stress testing, and how does it differ from the Modified Bruce Protocol?
The primary purpose of the Bruce Protocol is to evaluate aerobic capacity by gradually increasing treadmill speed and incline in standardized stages. The Modified Bruce Protocol starts at a lower intensity (2.7 km/hr. at 0% grade) to accommodate patients with lower fitness levels or those with cardiovascular limitations, making it more suitable for clinical populations.
How can the results of a CET inform exercise prescription for a patient with known coronary artery disease (CAD)?
For patients with CAD, exercise prescriptions are guided by the heart rate at which 2 mm ST depression occurred during the test. Exercise intensity should be kept 10-15 bpm below this HR to ensure safety and prevent ischemic events during exercise sessions.
What are the key differences between absolute and relative contraindications for CET?
Absolute contraindications are conditions where exercise testing poses an immediate risk and should not be performed, while relative contraindications require careful consideration, as exercise testing can proceed if the benefits outweigh the risks. For example, severe hypertension is a relative contraindication, whereas acute MI is an absolute contraindication.
Why is minimal or no cool-down recommended during the recovery period of a CET, and what information can this period provide?
Minimal or no cool-down is recommended to intentionally stress the cardiovascular system and observe how quickly the ECG, heart rate (HR), and blood pressure (BP) return to baseline. This period can provide diagnostic information on post-exercise ST-segment changes and HR recovery, which are indicators of cardiovascular health.
What are the common reasons to stop a clinical exercise test (CET) prematurely, and why are these criteria critical?
Reasons to stop a CET include:
- Moderate to severe chest pain
- Significant drop in BP (>10 mm Hg)
- Patient request or severe dizziness
- ST-segment depression/elevation >2 mm
- Ventricular arrhythmias
- Hypertensive response (SBP >250 mmHg; DBP >115 mmHg). These criteria are critical to prevent adverse cardiac events and ensure patient safety during testing.
What are the potential complications of CET, and which is the most serious?
Potential complications of CET include cardiac arrhythmias (SVT, V-tach, V-fib), acute coronary syndromes (ischemia/angina, infarction), hypotension, syncope, stroke, and death (1 in 10,000 tests). The most serious complication is sudden cardiac death, although it is rare.
How is the Short Physical Performance Battery (SPPB) used in clinical assessment, and what is its significance in predicting health outcomes?
The SPPB assesses lower extremity function through balance, habitual gait speed, and chair rise tests, scoring up to 12 points. Scores below 10 indicate mobility limitations and predict mortality, while scores below 7 indicate a high risk of nursing home admission. It is particularly valuable in assessing frailty and functional capacity in older adults or those with cardiometabolic disease.
What are the differences between the Bruce Protocol, Modified Bruce Protocol, and Naughton Protocol in CET?
The Bruce Protocol involves rapid increases in speed and grade, suitable for fitter individuals. The Modified Bruce Protocol starts with lower intensity, making it suitable for clinical populations. The Naughton Protocol increases workload more gradually, often used for patients with severe limitations or cardiovascular conditions.
Describe the typical equipment setup for conducting a CET and explain the role of each component.
The typical equipment setup includes:
- 12-lead ECG: Monitors heart rhythm and detects abnormalities
- Treadmill or bike: Provides graded exercise to increase cardiovascular demand
- BP monitoring device: Tracks blood pressure responses during exercise
- Automated external defibrillator (AED): For emergency response to cardiac events
What are the four primary reasons for conducting a clinical exercise test (CET) in patients with cardiovascular concerns?
The four primary reasons are:
- Post-CABG or post-angioplasty evaluation to determine if coronary flow has improved
- Diagnosis or treatment of exercise-induced arrhythmias
- Follow-up after cardiac rehabilitation to assess heart tolerance to increased exertion
- Screening for individuals with a family history of heart disease and risk factors
How should a CET be adapted for a patient with left main coronary artery stenosis?
Exercise testing should be approached with extreme caution, as this is a relative contraindication. The test may be performed if the benefits outweigh the risks, with strict monitoring of ECG, blood pressure, and symptoms, ensuring emergency equipment is available.
What factors should be documented regarding medication use before conducting a CET, and why is this important?
Documenting medications like beta-blockers and anti-hypertensives is crucial because they can alter HR, BP responses, and exercise tolerance, potentially affecting the interpretation of test results and safety thresholds.
