Week 9: CAD & post MI - Ex management Flashcards
What are the key elements monitored during the aerobic capacity assessment in patients with CAD or post-MI, and why are they important?
The key elements include peak aerobic capacity (VO2), peak workload, symptoms such as angina, dyspnea, claudication, heart rate (HR), and blood pressure (BP) response to exercise, as well as ECG monitoring. These factors are critical for determining exercise tolerance, identifying symptom limitations, and establishing safe exercise intensity levels.
How does the 6-Minute Walk Test (6MWT) predict mortality risk in patients with CAD or post-MI?
The 6MWT measures overground walking capacity, with a distance of less than 350 meters associated with increased mortality risk. It serves as an indicator of functional impairment and helps identify limitations in walking ability.
Describe the three phases of Cardiac Rehabilitation (CR) in Australia and their key objectives.
- Phase I: Inpatient phase focusing on mobilization and education for resumption of Activities of Daily Living (ADLs).
- Phase II: Begins after hospital discharge; involves up to 12 weeks of supervised exercise with ECG monitoring, and education on risk factor management.
- Phase III: Maintenance phase emphasizing ongoing healthy lifestyle changes.
Explain how beta-blockers influence the angina/ischaemic threshold in exercise prescription for CAD patients.
Beta-blockers lower heart rate and blood pressure, effectively raising the angina/ischaemic threshold, allowing patients to exercise at a higher workload before reaching their angina threshold. Exercise prescription must consider this adjustment to ensure safety.
What are the common adaptations to endurance training that impact the angina/ischaemic threshold in patients with CAD?
Endurance training leads to reduced heart rate (HR) for the same absolute intensity, an increased workload at the same relative intensity, and improved myocardial oxygen consumption (mVO2), resulting in a raised angina/ischaemic threshold.
Why is a combination of aerobic and resistance training recommended for patients with CAD, and what are the specific benefits observed?
Combined aerobic and resistance training enhances both cardiovascular fitness and muscle strength more effectively than aerobic training alone. It improves VO2 peak, work capacity, and strength, contributing to better overall functional capacity and reduced cardiac event risks.
How should exercise intensity be prescribed for patients with stable angina, and what is the significance of the ischaemic threshold in this process?
Exercise intensity should be set 10-15 bpm below the heart rate at the ischaemic/angina threshold to avoid inducing angina. The ischaemic threshold ensures exercise remains within safe limits, reducing the risk of exacerbating symptoms.
What safety considerations must be taken into account when prescribing resistance training to CAD or post-MI patients, and why?
Resistance training should avoid excessive volume, holding breath (Valsalva maneuver), and sustained isometric contractions to prevent undue rises in blood pressure (BP) and heart rate (HR). Higher intensities with lower repetitions are generally safer than lower intensity with high volume, which may increase cardiovascular strain.
After a Coronary Artery Bypass Graft (CABG), what exercise modifications are necessary, and why is sternal stability a concern?
Post-CABG patients should avoid heavy lifting, rapid arm movements, and exercises straining the chest to prevent sternal instability, a condition where the sternum does not heal properly post-surgery. Gradual progression with modified exercises ensures proper healing and minimizes complications.
How does exercise training prevent or delay restenosis in post-PCI patients, and what exercise protocol is most effective?
High-Intensity Interval Training (HIIT), involving intervals at 80-90% of Maximum Heart Rate (MHR), improves endothelial function, delaying luminal loss and reducing restenosis rates. Supervised, structured exercise, beginning around 11 days post-PCI, significantly improves cardiovascular outcomes.
Discuss the rationale for using the Rate Pressure Product (RPP) as a measure of the angina/ischaemic threshold in exercise prescription for CAD patients.
The Rate Pressure Product (RPP), calculated as HR × systolic BP, reflects myocardial oxygen demand. It helps identify the angina/ischaemic threshold since angina occurs at a specific RPP. By exercising below this threshold, the likelihood of inducing ischemic symptoms is minimized, ensuring safer exercise for CAD patients.
How does the principle of specificity apply to exercise prescription for enhancing aerobic capacity in post-MI patients?
The specificity principle states that exercise adaptations are specific to the type, intensity, and duration of activity. For post-MI patients, aerobic activities that mimic daily functional demands (e.g., walking or cycling) at intensities 50-80% of VO2 peak lead to improved cardiovascular efficiency, optimizing functional recovery.
Explain the impact of revascularization procedures, such as CABG and PCI, on exercise tolerance and prescription in CAD patients.
Revascularization improves blood flow and myocardial oxygen delivery, increasing exercise tolerance. Post-procedure, exercise prescription should gradually progress as healing occurs, with initial monitoring for symptoms like angina or arrhythmias. Long-term, exercise helps maintain vascular health and prevent restenosis or graft occlusion.
Describe the mechanism by which High-Intensity Interval Training (HIIT) influences endothelial function and its implications for CAD management.
HIIT induces shear stress on blood vessel walls, promoting nitric oxide production and improving endothelial function. This enhances vasodilation, reducing arterial stiffness and improving blood flow, which is crucial in managing CAD by delaying restenosis and reducing cardiovascular event risk.
Critically evaluate the use of 1RM testing in patients with left ventricular dysfunction post-MI and the implications for exercise prescription.
1RM testing in post-MI patients with left ventricular dysfunction is controversial due to the potential cardiovascular strain. However, studies show that peak HR and systolic BP during 1RM testing are lower than during graded exercise tests, suggesting that, with careful monitoring, 1RM testing can be safely incorporated to assess strength and inform resistance training prescriptions.
