Cardiovascular- Exercise Tolerance Testing and Exercise Prescription Flashcards
Primary purpose of Exercise Tolerance Testing (ETT)
- to determine physiological responses during a measured exercise stress (increasing work loads)
- allows the determination of of functional exercise capacity of an individual and detects presence of ischemia
Additional reasons for ETT
- serves as basis for exercise prescription and typically done before phase 2 of outpatient cardiac rehab
- used as outcome measure for cardiac rehab
- screening measure for CAD in asymptomatic patients
What is ETT with radionuclide perfusion?
- pharmacological stress test used when a patient is unable to perform a regular ETT
- common meds used to increase cardiac demand are adenosine (increases HR), dobutamine (increases contractility), and persantine (vasodialtes)
- imaging is used to detect decreased blood flow to myocardium
Testing modes for ETT
treadmill cycle ergometry (LE or UE) step test (standing or sitting)
What is maximal ETT
defined by target end point HR. Max ETTs should only be completed in settings with advanced cardiac life support trained staff
3 methods for determining Max HR
- Age predicted: 220-age (highest degree of error)
- 208- [0.7 x age] (less error)
- Karvonen’s formula 60% - 8-% (HR max - resting HR) + resting HR = target HR (provides HR range)
What is submax ETT
- symptom related or terminated at 85% of age predicted HR max
- safe in all settings
- used to evaluate the early recovery of patients after MI, CABG or angioplasty
Difference between continuous and discontinuous (interval) ETT
Continuous- workload steadily progressed. For ramp test, workload increased every min. For step test workload increased every 2-3 min
Discontinuous- allows rest in between workloads/stages. Used for patients w/ pronounced CAD.
Difference between positive and negative ETT
Positive- indicates myocardial O2 supply is inadequate to meet the myocardial O2 demand. + for ischemia
Negative- indicates that at every tested physiological workload there is a balanced O2 supply and demand
Difference between false positive and false negative ETT
False positive- interpreted as positive but there is no ischemia
False negative- interpreted as negative but patient has ischemia
What does the 6 min walk test have to do with ETT
highly correlated to other ETT, submax and Max VO2
Specific items to monitor in patient during exercise and recovery
persistent dyspnea dizziness or confusion anginal pain severe leg claudication excessive fatigue pallor, cold sweat ataxia, incoordination pulmonary rales changes in HR Changes in BP Rate pressure product (RPP)
Normal HR changes with exercise
HR increases linearly as a function of increasing workload and O2 intake, plateaus just before max O2 uptake (Vo2 Max)
Normal BP changes with exercise
systolic BP should increase but diastolic should remain about the same
What is RPP
- product of systolic BP and HR, used as index of myocardial consumption (MVO2)
- increased MVO2 = increased coronary blood flow
- angina is usually precipitated at a given RPP
The RPE scale AKA the Borg
- patients rate feelings during exercise and impending fatigue
- increases linearly with increased exercise intensity and correlates well with HR and work rate
- has intra-user reliability over time but not inter-user reliability
- important measure for patients w/out typical rise in HR such as those on beta-blockers
- original borg is 6-20, 7 = very,very light, 13 = somewhat hard, 19 = very, very hard
- modified borg 1-10, 1 = are we even doing anything here? to 10 = are you trying to kill me?
ECG changes you may see in a normal healthy adult
- Tachycardia, proportional to exertion/intensity
- rate related shortening of QT interval
- ST segment depression, upsloping, less than 1 mm
- reduced R wave, increased Q wave
- exertional arrhythmias, rare, single PVCs
ECG changes with exercise in patient w/ myocardial ischemia and CAD
- significant tachycardia at lower intensity, can also occur in very deconditioned folks w/out ischemia
- exertional arrhythmias, increased frequency of ventricular arrhythmias
- ST segment depression, horizontal or down sloping, greater than 1 mm
Delayed, abnormal responses to exercise which can also occur hours later
prolonged fatigue
insomnia
sudden weight gain from fluid retention
hypotension (especially HF patients)
What is telemetry
- allows for ambulatory and continuous 24- hour ECG monitoring
- ## can catch arrhythmias, ST segment changes, and silent ischemia
What is transtelephonic ECG monitoring
used to monitor patients as they exercise at home
Metabolic Equivalents (METS)
- MET is the amount of O2 consumed at rest, 3.5 mL/kg per min
- can be determined during ETT
- can be estimated during ETT during steady state exercise, the Max VO2 acheived on ETT is divided by resting VO2, highly predictable w/ standardized testing modes
Ex: 2-3 METs walking 2 mph
4-5 METs walking 3.5 mph
7-8 METs jogging
8-9 METs running
Exercise Prescription: Interval training in early rehab
- activity is discontinuous (interval training) with frequent rest periods progressing to continuous training
- can also be incorporate in vigorous training to allow pt. to work at higher % of VO2 max
Exercise Prescription: warm up & cool down
- gradually increase or decrease intensity of exercise , promote circulatory and muscular adjustment to exercise
- Type: low intensity cardio-respiratory endurance activities, flexibility (ROM) exercises, functional mobility exercises
- Duration 5-10 min
- abrupt beginning or cessation of exercise is not safe nor recommended