BCIT - Test 2 M5-9 - ETT - CARD 4202

Exercise Stress Testing is routinely performed on patients who:

are chronic, stable and asymptomatic; have known or suspected left ventricular dysfunction, or are recovering from an acute myocardial infarction, percutaneous coronary angioplasty or coronary artery bypass grafting.

For patients with existing cardiovascular disease, the exercise stress test can be used for many purposes, which include:

To quantify the functional or clinical significance of disease

To aid in determining appropriate medical management or therapy

To assess the effectiveness of various treatment regimes

To promote patient confidence in physical activity

To establish exercise appropriateness

For prognosis of future events

The majority of exercise work intolerance is due to:

a decrease in peak stroke volume or heart rate

Special considerations when exercising a patient with known cardiovascular disease include:

Absolute and relative contraindications, excluding patients that are at high risk due to medical conditions

Selecting an appropriate protocol for the individual being assessed

Monitoring the patient closely for clinical indications or contraindications for testing

Prevention and therapy for CHD involves maintaining or re-establishing balance between myocardial oxygen supply and demand.

Supply can be increased by:

Decreasing the rate with which coronary atherosclerosis develops or regresses

Forming collateral coronary arteries

Enlarging the diameter of major coronary vessels

Redistributing coronary blood flow

Improving function of the clotting or fibrinolytic system

Other lifestyle changes that ameliorate or maintain myocardial oxygen supply include:

Smoking cessation

Treating hypertension

Treating hyperlipidemia

Reducing dietary saturated fats

Reducing cholesterol

Reducing salt intake

Maintaining optimal body weight

Exercising to modify lipoprotein and carbohydrate metabolism and platelet aggregation

The BMI is a height-to-weight ratio and has four ranges:

Underweight (less than 18.5)

Normal weight (between 18.5 and 24.9)

Overweight (between 25 and 29.9)

Obese (30 and over)

Obesity is one of the leading causes of cardiovascular disease (Health Canada, 2006)

When subjecting an individual who is overweight or obese to exercise, one should consider:

Whether the patient has been screened by a physician prior to testing

Musculoskeletal and/or orthopedic conditions that may require modification to the protocol or type of exercise administered

Whether the individual has a low exercise capacity and will have difficulty achieving the criteria for maximal stress testing

Obesity is defined as an excess of body fat, as compared to overweight, which is defined as an excess of body weight relative to height.

The advantages of using BMI are that it is easy to measure, inexpensive, and reproducible.

Amount and distribution of fat in the body are equally important.

Fat in the abdominal region is more closely related with the development of chronic diseases such as coronary artery disease (CAD) and Type 2 Diabetes than is fat distributed elsewhere on the body.

Obesity Associated conditions and risks

- Morbidity (conditions) and mortality (death)

- Osteoarthritis

- Cancer

- Type 2 diabetes

- Hypertension

- Hyperlipidemia

- CVD

Exercise and Obesity

The heart must work harder in order to move a heavier body. The limiting factor in patients with obesity is the submaximal aerobic capacity rather than the cardiovascular system, but with a higher submaximal heart rate, respiratory exchange ratio, %VO2max, and shorter time to exhaustion. Heat tolerance can also become a factor limiting work capacity in obesity.

Diabetes mellitus (DM)

6th or 7th leading cause of mortality in the US. DM can cause visual impairment, blindness, and renal failure.

Diabetes mellitus (DM) symptoms

Fatigue

Weakness and weight loss

Hunger (polyphagia)

Thirst (polydipsia)

Frequent urination (polyuria)

Elevated blood sugar (hyperglycemia)

Sugar is found in the urine (glycosuria)

Acetone is found in both the blood and urine (ketosis)

Probable causes of DM include:

Predisposing diabetogenic factors

Viruses and autoimmune mechanisms

Obesity

Physical inactivity

Diet

Aging

Certain endocrine disorders

Certain medications/drugs

Pancreatic and liver disease

Stress

Types of DM

Insulin-dependent Diabetes Mellitus IDDM (type I)

Non-insulin-dependent Diabetes Mellitus NIDDM (type II)

Malnutrition DM

Secondary types associated with various medical conditions

Individuals with IGT (Impaired Glucose Tolerance) will show elevated level of plasma glucose but they are not usually high enough for diagnosis of DM.

Risk factors of Diabetes M

-mumps and coxsackie B viruses (type 1)

-viral damaged islet cells acting like antigens result in antibody production.

-Both parents have DM (4-6x greater chance) (type 2)

-Individuals with pre type 2 who develop abdominal fat

- obesity and central body fat (type 2)

- Age, reduced physical activity, lean body mass, and increase in adiposity

Diabetes mellitus is a:

heterogeneous group of metabolic disorders caused by actual or relative insufficiency of insulin secretion. Insulin is a peptide hormone synthesized in ß cells of pancreatic islets. It transports glucose across cell membranes for energy production. Insufficiency of insulin reduces the ability of tissues (skeletal muscle) to use glucose as a fuel. The ability to synthesize glycogen is also defective. The end result is hyperglycemia in the blood.

Treating the metabolic effects of DM is life-long

The ultimate goal is to control glucose and eliminate any symptoms related to hyperglycemia. A second goal is to prevent or reduce the severity of chronic complications and to allow the patient to achieve a more normal lifestyle.

There are 3 essential therapeutic approaches for glycemic control:

Medications

Diet

Regular exercise

Oral hypoglycemic agents (OHAs)

OHAs can control blood sugar levels in patients with type 2 DM who have difficulty responding or following a specific diet and/or exercise.

Insulin therapy

The role of insulin therapy is to 1) treat and prevent ketoacidosis with type 1 DM and 2) control symptoms associated with the metabolic derangements. Once blood glucose levels are determined, insulin is administered progressively through the subcutaneous tissue.

Type 2 DM patients with hyperglycemia require insulin for initial therapy. This can be combined with hypoglycemic agents if glucose levels cannot be controlled this way

Insulin pumps are another way of controlling DM. These are small instruments, which are worn outside the body. The pump administers insulin subcutaneously over the course of the day.

HTN is defined as:

SBP of ≥ 140 mmHg and or a DBP of ≥ 90 mmHg.

HTN risk factors:

result of genetic and environmental factors and their interactions. Other primary risk factors include: age,

body mass (excess body fat),

excessive sodium intake,

increased alcohol intake,

inactivity,

and family history.

Men have a higher incidence of HTN than women.

The relationship between BP, flow, and resistance is a simple and direct one:

BP = cardiac output (Q) x systemic vascular resistance (SVR)

According to the World Health Organization (WHO), there are 3 stages of HTN:

Stage 1

· Higher resting HR and Q without increase in SV

· No objective signs of organ damage

Stage 2

· Gradual drop in Q

· Continuous rise in SVR

· Normal Q, HR, SV once HTN becomes established

· Evidence of one or more of the following: enlarged heart, narrowing of the arteries in the eye

· High levels of urinary protein

Stage 3

· Further increase in SVR

· Below normal Q

· Signs and symptoms of damage to: the heart, brain, eyes and kidneys

Lifestyle modification and medications are the two general treatments for HTN.

Losing weight (body fat)

Reducing alcohol intake

Regular exercise

Smoking cessation

Diet modification

Reducing sodium intake

Maintaining dietary levels of potassium, magnesium and calcium

The type of drug prescribed depends on the hemodynamic pattern in each stage of HTN.

Stage 1

Beta blockers - decrease Q and HR

Calcium channel blockers - decrease Q by reducing strength of ventricular contraction

Diuretics - increase urination to reduce plasma and extracellular volumes (also SV and Q)

Stage 2 / - more advanced - goal to reduce SVR

Alpha receptor blockers - dilate the arteries

ACE - reduce the ability of arterial smooth muscle to contract

if known CVD use nitrates - dilate the vessels

Effects of exercise on BP

Systolic Blood Pressure (SBP) rises with an increase in dynamic movements; blood volumes increase in those muscles contributing to the movement.

Diastolic Blood Pressure (DBP) does not change for the most part.

With mild to moderate hypertension, Q increases, whereas SBP, DBP and SVR are higher at all levels of exercise compared with healthy people.

Patients taking medication for HTN should not stop exercising, although some medications can affect their ability to exercise.

- β-blockers help CVD and angina patients to exercise at higher levels because it reduces the work of the heart.

- Diuretics can cause dehydration and a subsequent loss in potassium. This in turn can produce irregular heart rhythms, but has little effect on the ability to exercise.

- Ace inhibitors, Ca2+ channel blockers and α-blockers do not seem to have any adverse affect on the ability to exercise.

Pulmonary disease

may cause shortness of breath on exertion or dyspnea, which may limit exercise capacity.

Two common types of pulmonary disease encountered in the cardiology setting are

chronic obstructive pulmonary disease (COPD) and asthma.

COPD is an irreversible disorder that consists of chronic bronchitis, emphysema and cystic fibrosis.

Asthma is a reversible obstruction caused by bronchospasm and inflammation.

When subjecting an individual who has mild COPD or asthma, one should consider:

Modifying protocols for extended stages with smaller increments and slower progression

Use of sub-maximal testing

Exercise testing may be terminated due to severe arterial desaturation of oxygen

Environmental factors such as air quality, humidity and temperature may influence exercise capacity

Asthma is a chronic inflammatory disorder of the airways in which many cells and cellular elements;

mast cells, eosinophils, T lymphocytes, macrophages, neutrophils, and epithelial cells - all play a role.

It causes wheezing, breathlessness, chest tightness, and coughing, especially at night or in the morning.

Asthma is one of the most common respiratory disorders:

The first episode can occur at any age.

It is more common in boys than girls (by a 3:2 ratio),

and more common in older women than older men.

Asthma is characterized by

a limitation of airflow by mucosal edema, impaired mucociliary function, and contraction of the airway smooth muscle.

Exercise Induced Asthma (EIA) can be classified as mild, moderate or severe.

The cause of EIA and EIB are unknown at present.

The best hypothesis thus far for EIA is that it is caused by release of a broncho-active mediator in response to changes in periciliary fluid osmolarity.

Should inhale though nose to warm airways

Osteoporosis

characterized by bone loss that increases skeletal fragility and fracture risk.

It occurs mostly in women and accelerates during menopause - a woman can lose up to 20% of her bone mass during this time

Osteoporosis is often referred to as the

"silent disease".

Osteoporosis does not produce any noticeable symptoms, and therefore, there does not seem to be any pain associated with the bone loss

Rheumatoid arthritis (RA) is

the most common of all arthritic diseases whose etiology is unknown.

RA is a chronic, progressive, autoimmune systemic disease.

Its key feature is inflammation of the joint lining - the lining thickens and interferes with joint mobility.

Extra fluid in the joint space (bursa sac) causes swelling, and the joint becomes painful with motion and touch.

Mose commo joint are foot, fingers and wrists

Rheumatoid arthritis is classified into four stages:

In the first stage, bone changes can be seen using a radiograph

As the arthritis progresses into the second stage, muscles begin to waste away. Movement and range of motion become limited

In stage three, Joint defects occur, increase in muscle wasting, and bone and cartilage deterioration are observed.

In the fourth and final stage, fiber-like or bony joining - called ankylosis - of the inflamed tissue takes over the joint.

Osteoarthritis (OA) is

a chronic degenerative condition of the joints. It is related to physical activity, and can affect any diarthroidial joint.

Osteoarthritis is the most common type of arthritis. There are two forms;

one form of OA is related to aging and heredity, the other form can occur at any age and in any joint as a result of injury - repetitive joint use, fracture, or metabolic disease.

OA is a disease that combines the pathology of disease with pain that occurs when the joint is used.

The joint cartilage gets soft, less resilient, and thinner, which decreases the cushioning and mechanical forces in the joint.

Thickening of the synovium, laxity of the ligaments and weakness of the bridging muscles also affect the structure around the joint.

Most individuals with arthritis tolerate a symptom limited exercise test well. Some things to consider when testing this population:

Exercise testing should be avoided when their is acute inflammation

Although some may tolerate treadmill walking, the use of the cycle ergometer may be less painful and allow better cardiovascular assessment. The mode of exercise should be the least painful

Monitor pain levels during testing

Muscle fatigue, dyspnea, and maximum predicted heart rate are

the most common endpoints for the termination of an exercise test

The most common symptoms induced by exercise testing are

angina and dyspnea

predictor of CAD and multi-vessel disease

Heart rate normally increases proportional to exercise

A common method used to estimate age-predicted maximum heart rate is: Max HR = 220 minus the age, with a target heart rate (usually) being 85% of that.

A normal blood pressure response to exercise is a progressive increase

There is usually very little change to the diastolic blood pressure. Normal blood pressure values vary with exercise (160-220/50-90).

Hypertensive blood pressure response is usually described as

>220 mmHg systolic and >90 mmHg diastolic

Exercise should be discontinued when the systolic pressure reaches 250 mmHg or the diastolic pressure reaches 115 mmHg

Hypotensive

severe ischemic heart disease or heart failure

A drop of 10 mm in systolic pressure during exercise may indicate presence of myocardial ischemia or left ventricular dysfunction.

METS (metabolic equivalents)

resting oxygen consumption of about 3.5 mL per kg per minute

Normal electrocardiographic changes that occur during exercise include:

rate-related shortening of the Q-T interval and superimposition of the P and T waves,

decreasing R wave amplitude and increasing T wave amplitude.

ST segment changes are the most reliable electrocardiographic indicator of ischemia.

There are 6 different types of ST segment changes

Isoelectric

Junctional

Horizontal Depression

Downsloping

Slow rising

Elevated

Horizontal or downsloping depression ≥1.0 mm below the baseline, lasting 60-80 milliseconds beyond the J-point, is accepted as significant evidence of myocardial ischemia.

Digitalis may also be a factor

Myocardial oxygen demand is determined mainly by

heart rate, ventricular wall tension and contractility

Exercise-induced ST elevation in leads with pathological Q waves

indicating an old myocardial infarction, suggests an aneurysm or wall motion abnormality

The failure to generate sinus tachycardia is an abnormal finding and

may indicate chronotropic impairment

The criteria for terminating an exercise test due to ventricular activity include:

sustained ventricular tachycardia, multifocal PVCs, or episodes of non-sustained ventricular tachycardia.

Digitalis

can cause exercise-induced ST depression in a patient's ECG segment

Diuretics

can cause a patient to experience muscle fatigue and ventricular ectopy during exercise

Calcium Channel Blockers

can decrease heart rate and systolic blood pressure during exercise as well as delay ischemia and improve a patient's exercise capacity

Beta Blockers

can allow patients to reach a higher exercise capacity with less chest pain and fewer ST changes. With the use of beta blockers, the maximum HR and BP are reduced, and therefore it is difficult to reach the patient's MAX HR

Vasodilators

are often used in the treatment of heart failure and can allow subjects with heart failure or angina an increased exercise capacity

Angiotensin-Converting Enzyme Inhibitors

are used to control blood pressure and therefore allow the patient to increase their exercise capacity

Absolute indications generally means

the test should be terminated, but in some cases an attending physician may insist on continuing, based on clinical knowledge

Relative indications, on the other hand,

are more ambiguous and require critical thinking, experience, and close observation in order to make a decision to proceed or terminate.

Absolute indications for termination

Decrease in systolic blood pressure of >10 mm HG from baseline, with an increase in exercise when associated with other evidence of ischemia

Moderately severe angina

Increasing nervous system symptoms

Signs of poor perfusion

Technical difficulties

Patient requests termination

Sustained ventricular tachycardia

ST elevation of > 1 mm in leads without significant Q waves (exempt is V1 and aVR)

Relative indications for termination

Decrease in systolic blood pressure of <10 mm Hg from baseline, with an increase in workload but no other evidence to suggest myocardial ischemia

ST or QRS changes

Arrhythmias (excluding ventricular dysrhythmias)

Physical symptoms including shortness of breath, leg cramps or fatigue

Development of an intraventricular conduction delay or bundle branch block that cannot be differentiated from a ventricular dysrhythmia

Worsening chest pains

Hypertensive response with the systolic blood pressure being >250 mm Hg and/or the diastolic blood pressure being >115 mm Hg

The predictive value of exercise stress testing in the detection of coronary artery disease is determined by

the specificity and sensitivity of the test

Sensitivity refers to

the number of times that a test gives an abnormal or positive result when those with cardiovascular disease are tested.

false-negative occurs when

there are not abnormal changes, yet the person being tested does indeed have cardiovascular disease. A number of factors can cause false negatives which include:

Technical or observation error

Musculoskeletal limitations

Significant CVD compensated by significant collateral circulation

Failure to recognize symptoms that are associated with CVD

ECG monitoring using fewer than 12 leads

Failure to reach an ischemic threshold

Specificity refers to

the number of times that a test gives a normal or negative result when those without cardiovascular disease are tested.

A false-positive occurs when

there are abnormal ST changes in the absence of significant obstructive coronary artery disease. Some common causes of ST changes which may be misinterpreted as positive for CVD include:

Resting repolarization abnormalities (bundle branch block)

Cardiac hypertrophy with strain pattern

Accelerated conduction abnormalities

Digitalis

Cardiomyopathy (except ischemic cardiomyopathy)

Hypokalemia

Pericardial disorders

Female sex

Anemia

The diagnostic accuracy of exercise stress testing can be improved by

adding an imaging modality. This addition can improve the sensitivity from around 65% to between 85% and 90%.

Radionuclide imaging is a useful way to determine

ischemia and infarction from coronary artery disease.

This technique involves the injection of radioactive isotopes, generally thallium-201 and technetium-99m sestamibi, and image acquisition using single photon emission computer tomography (SPECT)

The intracellular concentration of thallium is estimated based on

the density of the image, and depends primarily on two factors: (1) vascular supply and (2) membrane function.

To evaluate for ischemia, an initial set of images is taken right after exercise (controlled physical or pharmacological) and thallium injection, and then several hours later. A normal heart should show homogenous distribution of radioactive tracer throughout the myocardium.

Scarred areas show a lack of thallium distribution. "clod spots". If after the second image they are gone, the ischemia is considered reversible.

99m sestamibi (also referred to as MIBI) demonstrates the relationship between

the amount absorbed by the myocardium in relation to the blood flow at rest and post exercise. Images are usually taken with a low dose of tracer at rest, and then with a higher dose of tracer peak exercise (controlled physical or pharmacological). In both cases, the patient may be asked to eat a fatty snack, such as milk or cheese, to help their body absorb the tracer.

Indications for radionuclide imaging include:

Diagnosing coronary artery disease (CAD), especially in patients with suspected false-positive or false-negative ETT, or ST-T abnormalities (LBBB, RBBB with strain, Wolff-Parkinson-White syndrome, digitalis effect, etc.)

Evaluating patency of coronary bypass grafts

Determining the physiological significance of known CAD

Detecting jeopardized myocardium after MI

Diagnosing, sizing and locating acute MI

Providing differential diagnosis of ischemic versus idiopathic cardiomyopathy

Determining myocardial involvement in patients with sarcoidosis

Assessing viable myocardium to determine treatment (e.g. revascularization, transplant)

When nuclear medicine imaging is combined with the drug Persantine (dipyridamole), the test is called

a Persantine MIBI. Persantine is an alternative to exercise induced stress, in patients who are unable to adequately exercise due to physical disabilities (peripheral vascular disease, elderly, etc). It mimics exercise by causing vasodilation without causing a change in heart rate.

Aminophylline may be given if there are any adverse effects. Causes vasoconstriction.

Contraindications to performing a persantine MIBI

Caffeine within 24 hours and asthma

Dobutamine is another alternative medication used to mimic exercise

Dobutamine is a direct-acting agent whose primary activity results from stimulation of the β1-adrenoceptors of the heart, increasing contractility, HR and cardiac output.

Used when there are contraindications to persantine. takes longer typically.

Just like the previous two MIBI protocols, Persantine

have resting and stress images that are compared in addition to the ECG tracings. A positive test would indicate a decrease in myocardial blood flow with exertion.

Stress echocardiography is primarily used to

diagnose coronary artery disease, by determining if there are any wall motion abnormalities resulting from physical exercise or drug-induced stress (Dobutamine), which may indicate ischemia.

The dobutamine stress echo is a valuable diagnostic tool that allows the cardiologist to assess a number of different things including:

The overall function of your heart's valves and chambers

The clinical manifestations of many types of heart disease such as valvular problems, myocardial disease, pericardial disease, coronary artery disease and congenital heart disease

Monitoring, evaluation and follow-up of medical treatments (drugs) or surgical procedures

In addition to treadmill exercise stress testing, an exercise test may be performed on a bike.

It's the time between stages and the amount of resistance that is added at each stage that makes these protocols different.

One advantage to the bike stress test is there is less movement of the patients upper body so it is easier to obtain a better quality ECG and BP. The ergometers are also less expensive, and take up less room.

bike is less familiar than walking and can induce leg fatigue

called CPX or Cardio Pulmonary Exercise tests

Cycle ergometer stress tests are quite often combined with pulmonary function testing with a respiratory therapist.

Tilt-table testing is a non-invasive diagnostic test

used to evoke a neurocardiogenic event in those with suspected vaso-vagal syncope. It is indicated for those with episodes of light-headedness, dizziness, or unexplained syncope.

increase in vagal tone and decrease in sympathetic tone. Increased blood pooling in lower extremities, causing decrease in blood pressure and venous return.

The technologist performs the tilt-table test under the close supervision of a physician and is responsible for:

Calibration and maintenance of the exercise testing equipment

Explanation of the procedure to the patient; demonstration of technique and safety involved in performing the test

Obtaining the written consent from the patient

Physical preparation of the patient

Monitoring and recording electrocardiographic data and the patient's blood pressure, and reporting any changes to the physician

Making sure medications are accessible to the attending physician

Observing the patient's physical/emotional reaction and reporting any changes to the physician

Documenting all findings, medications given, and the patient's response to such medications for the physician

Terminating the test when the predetermined endpoint is reached or when indicated by the attending physician

Preparing a basin in the case of patient nausea

Responsibilities of the physician before and during the tilt-table test are:

Evaluating the patient before the procedure

Selecting the appropriate medications and administering them

Monitoring the patient during the procedure

Interpreting the test

Patient Preparation: Tilt T

Check the patient's name and birth date

have nothing to eat or drink after midnight the night before the test.

The patient may also be requested to hold specific medication by their cardiologist or physician.

consent is signed,

the patient is hooked up to an electrocardiograph monitor

The patient will also receive an IV that will be used to administer medications if necessary

take a detailed list of the patient's medications

and confirm that the patient has arranged transport home

patient is strapped snuggly to the table with a thick strap.

Patient Monitoring and Electrode Application: tilt

alcohol, abrade skin, shave the men, apply electrodes.

Upper limb leads: high on the shoulders or clavicles

Lower limb leads: bottom of the rib cage

V1: fourth intercostal space at right sternal border

V2: fourth intercostal space at left sternal border

V3: mid-point between V2 and V4

V4: fifth intercostal space at midclavicular line

V5: same level as V4 at anterior axillary line

V6: same level as V4 and V5 at mid-axillary line

Measurements: tilt

It is at the discretion of the physician whether or not they want to administer pharmaceuticals, and at what dose and interval.

ECG and BP in supine position prior to test

The heart beat and BP is monitored continuously, and recordings are made at specific intervals pre-test, during the test, and in recovery.

Patients should be queried frequently for symptoms of light-headedness, dizziness, or nausea.

The patient is usually kept in a recovery position until instructed otherwise by the physician. This may be a longer period of time, if the test was extremely positive.

The main parameters observed during the tilt-table test are the patient's

blood pressure, heart rate, and rhythm

a positive test will be accompanied with rhythm changes that include an initial tachycardia, sinus arrhythmia or sinus rhythm followed by an abrupt sinus arrest and/or bradycardia, a fast or normal heart rate followed by a sudden slow heart rate, and a decrease in blood pressure.

This may include an intravenous infusion, or bolus injection of isoproternol (Isuprel), or nitroglycerine. Using a drug challenge increases the probability of a positive test.

In extremely positive cases, the patient will experience: Tilt

syncope by simply tilting the bed to the standard 80° angle without the use of a drug challenge.

Medications Administered during a Tilt-Table Test

Isoproterenol - has cardiovascular effects that mimic exercise with a positive inotropic and vasodilatory effect. The major downfall of this medication is the risk of tachycardia and other arrhythmias, as well as side effects that include a drop in blood pressure, headache, tremor, and sweating.

Nitrates - Often referred to simply as "nitro," these potent coronary vasodilators act as antianginals. However, more importantly for this test, they cause coronary vasodilation. They redistribute blood flow to collateral arteries and from epicardial to endocardial surfaces, and cause a reduction in preload and afterload. Side effects, headache, syncope, tachycardia.

Contraindications to medications include: Tilt

Hypertrophic obstructive cardiomyopathy

Acute inferior wall myocardial infarction with right ventricular involvement

Corpulmonale

There are three main criteria for termination of a tilt-table test. These include:

Syncope (positive test)

Positive test

As requested by the physician

Children's sizes may cause difficulties in exercising them

The Bruce protocol is preferred; however, a modified Bruce protocol may be required for smaller children, so that the speed of the treadmill is kept constant after the fourth stage and only the grade increases. Children can take only very small steps and, above 3.4 miles per hour, the number of strides becomes markedly increased.

other things to consider when selecting the appropriate protocol for children

attention span, age, reason for testing, and equipment available.

Two-minute stages seem to be an effective time interval, because children reach steady state faster than adults.

Several reasons why exercise testing may be done in young children include:

The physical working capacity or level of impairment can be determined.

Adverse reactions may suggest additional testing is required.

Controlled exercise may be used to assure the safety of exercise.

Adverse effects or the effects of a specific intervention on exercise capacity can be evaluated.