B P3 C15 Exercise Physiology and Exercise Electrocardiographic Testing

Question 1

Energy requirements at rest and for any given amount of physical activity (work rate) can be estimated from measurements of

Answer 1

Total-body oxygen uptake ( Vo2 )

Question 2

1 MET is resting energy expenditure and is approximately _____ mL O2/kg BW/min

Answer 2

3.5 mL O2/kg body weight/min

Question 3

________ peak oxygen uptake achieved during performance of the highest level of dynamic exercise involving large muscle groups and by definition cannot be exceeded despite increases in work rate.

Answer 3

VO2 max

Question 4

Stroke volume in healthy persons generally plateaus at _______ of Vo 2 max.

Answer 4

50% to 60%

Question 5

Myocardial oxygen demand is related to:

Answer 5

HR
BP
LV contractility (myocardial shortening per beat)
LV wall stres

Question 6

LV _________ is related to LV pressure, wall thickness, and cavity size.

Answer 6

LV wall stress

Question 7

_________ reliable index of myocardial oxygen demand and can be readily assessed clinically.

Answer 7

Rate-pressure product (product of HR and SBP)

Question 8

_________ reliable index of myocardial oxygen demand and can be readily assessed clinically.

Answer 8

Rate-pressure product (product of HR and SBP)

Question 9

During acute endurance (high-repetition/low-resistance) exercise (e.g., walking or cycling), ________ rises in response to the metabolic needs of the exercising muscles

Answer 9

Cardiac output

Question 10

Diminution of _______ and a rise in sympathetic tone lead to an increase in HR and LV contractility.

Answer 10

Vagal tone

Question 11

Stroke volume also rises because of increases in __________, and blood flow is redistributed from the renal, splanchnic, and cutaneous circulation to the exercising muscles.

Answer 11

Venous return of blood from exercising muscles

Question 12

Accumulation of metabolites in the actively contracting muscles causes __________ of muscle arterioles, which increases skeletal muscle blood flow up to four times that of resting levels and results in a reduction in aortic outflow impedance.

Answer 12

Vasodilation

Question 13

Systolic BP increases mostly because of the rise in cardiac output, whereas diastolic BP either remains _______ or ______ as a result of the reduction in vascular resistance.

Answer 13

Constant or falls

Question 14

Dynamic arm exercise elicits __________ at any given work rate than does dynamic leg exercise.

Answer 14

Higher HR and BP responses

Question 15

This type of exercise generates an increased sympathetic response, leading to an increase in HR; however, venous return, especially during straining, may decrease.

Answer 15

Resistance (low-repetition/high-load) exercise (e.g., weightlifting)

Question 16

The rise in cardiac output is relatively small in comparison to that achieved with endurance exercise and is primarily caused by ________ in HR

Answer 16

Increases in HR

Question 17

Muscle contraction during resistance exercise generates compressive force on muscle capillaries that leads to ______ peripheral resistance

Answer 17

Elevated peripheral resistance

Question 18

This rise in vascular resistance coupled with an increase in cardiac output yields an increase in both ___________

Answer 18

Systolic and diastolic BP

Question 19

In healthy persons during acute exercise, coronary arteries __________ and coronary blood flow __________ in response to the increases in myocardial oxygen demand.

Answer 19

Dilate and coronary blood flow rises

Question 20

In general, a 50% to 70% reduction in luminal diameter will _______ reactive hyperemia, whereas 90% or greater stenosis will _______ resting flow

Answer 20

Peak reactive hyperemia

Reduce resting flow

Question 21

Atherosclerotic arteries often _______________ thus further reducing the supply of blood in the setting of increased demand.

Answer 21

Fail to dilate and may actually constrict with exercise

Question 22

Absolute contraindications to Exercise Testing

Answer 22

Acute MI within 2 days
High-risk unstable angina
Uncontrolled cardiac arrhythmia with hemodynamic compromise
Active endocarditis
Symptomatic severe AS
Decompensated HF
Acute PE or pulmonary infarction
Acute myocarditis or pericarditis
Physical disability that precludes safe and adequate testing

Question 23

Relative contraindications to Exercise Testing

Answer 23

Known LM coronary artery stenosis
Moderate AS + uncertain relation to symptoms
Tachyarrhythmias + uncontrolled ventricular rates
Acquired complete heart block
HCM with severe resting gradient
Mental impairment with limited ability to cooperate

Question 24

More common form of physiologic stress (i.e., walking) in which patients are more likely to attain a higher oxygen uptake and peak HR than during stationary cycling

Answer 24

Treadmill testing

Question 25

_______ can be used as a surrogate measure of exercise capacity when standard treadmill or cycle testing is not available; best used in a serial manner to evaluate changes in exercise capacity and the response to interventions that may affect exercise capacity over time.

Answer 25

6-minute walk test Distance walked is the primary outcome of the test; not useful in the objective determination of myocardial ischemia

Question 26

Uses ventilatory gas exchange analysis during exercise to provide a more reliable and reproducible measure of Vo2

Answer 26

Cardiopulmonary exercise testing (CPX)

Question 27

________ the most accurate measure of exercise capacity and is a useful reflection of overall cardiopulmonary health.

Answer 27

Peak VO2

Question 28

CPX is well established as useful in the following situations:

Answer 28

*Evaluation of exercise capacity in selected patients with **heart failure**, to assist in **estimation of prognosis**, evaluate the **response to medications and other interventions**, and assess the need for **cardiac transplantation**. Evaluation of **exertional dyspnea**. Evaluation of the patient’s **response to specific therapeutic interventions** (e.g., medications; programmed pacing; cardiac rehabilitation) in which improvement in exercise tolerance is an important goal or endpoint.

Question 29

_____ angina is an important clinical predictor of the presence and severity of CAD, equal to or greater than STsegment depression

Answer 29

Exercise-induced angina

Question 30

_____ angina predicts an adverse prognosis and is worthy of further evaluation regardless of the ST-segment response or the exercise capacity.

Answer 30

Exercise-induced typical angina

Question 31

___________ is a strong predictor of mortality and nonfatal cardiovascular outcomes in both men and women with and without CAD.

Answer 31

Functional capacity

Question 32

Equations in estimating predicted METs

Answer 32

Men : Predicted METs = 18 − (0.15 × Age) Women : Predicted METs = 14.7 − (0.13 × Age)

Question 33

________is a fundamental physiologic parameter that provides the clinician relevant information concerning the intensity of exercise, the adequacy of the exercise test, the effect of medications that influence HR, the potential contribution to exercise intolerance, and the patient’s prognosis.

Answer 33

Maximum HR during exercise

Question 34

Equation to estimated HRmax

Answer 34

HRmax = 220 − Age

Question 35

Equations to generate maximum age-predicted HR (MPHR)

Answer 35

Men : HRmax = 208 − (0.7 × Age) Women : HRmax = 206 − (0.88 × Age)

Question 36

__________ is the inability of the heart to increase its rate to meet the demand placed on it. It is considered an independent predictor of cardiac or all-cause mortality, as well as other adverse cardiovascular outcomes.

Answer 36

Chronotropic incompetence

Question 37

A _____________ is assigned when the peak HR achieved is below the MPHR.

Answer 37

Submaximal study

Question 38

An ________ is defined by failure to achieve a predefined goal, such as 85% of MPHR.

Answer 38

Inadequate study

Question 39

Failure to achieve a chronotropic index higher than 80%; predicts a poor prognosis.

Answer 39

Chronotropic incompetence

Question 40

Abnormal HR recovery (HRR) has been defined by many methods, but the most commonly accepted include

Answer 40

Less than **12 beats/min** decrement after 1 minute with post-exercise slow walking cool-down Less than **18 beats/min** after 1 minute with immediate cessation of movement into either the supine or sitting position Less than **22 beats/min** after 2 minutes Abnormal HRR is associated with an increase in all-cause mortality in both asymptomatic individuals and patients with established heart disease

Question 41

Exercise BP responses

Answer 41

Increase: * Systolic BP * Pulse pressure (difference between systolic and diastolic BP) * HR-BP product (also called the double product), and double-product reserve (change in double product from peak to rest) all increase steadily Diastolic BP increases only minimally or may fall

Question 42

In most normal individuals, systolic BP will increase to well above _______ and the double product to higher than ________.

Answer 42

140 mm Hg 20,000

Question 43

Hypertensive Systolic Pressure Response

Answer 43

Men: > 210 mm Hg Women: > 190 mm Hg

Question 44

Exercise-Induced Systolic Hypotension

Answer 44

Systolic pressure during exercise falling below resting systolic pressure. Another definition is a 20 mm Hg fall after an initial rise.

Question 45

Absolute Indications for Terminating Exercise Test

Answer 45

• ST elevation (>1.0 mm) in leads without Q waves due to prior MI (other than aVR, aVL, or V1) • Drop in systolic BP of >10 mm Hg, despite an increase in workload, when accompanied by any other evidence of ischemia • Moderate to severe angina • Central nervous system symptoms (e.g., ataxia, dizziness, or near syncope) • Signs of poor perfusion (cyanosis or pallor) • Sustained ventricular tachycardia or other arrhythmia that interferes with normal maintenance of cardiac output during exercise • Technical difficulties monitoring the ECG or systolic BP • Patient’s request to stop

Question 46

Relative indications in terminating exercise test

Answer 46

• Marked ST displacement (horizontal or downsloping of >2 mm) in a patient with suspected ischemia • Drop in systolic BP of >10 mm Hg (persistently below baseline) despite an increase in workload, in the absence of other evidence of ischemia • Increasing chest pain • Fatigue, shortness of breath, wheezing, leg cramps, or claudication • Arrhythmias other than sustained ventricular tachycardia, including multifocal ectopy, ventricular triplets, supraventricular tachycardia, atrioventricular heart block, or bradyarrhythmias • Exaggerated hypertensive response (systolic blood pressure >250 mm Hg and/or diastolic blood pressure >115 mm Hg) • Development of bundle branch block that cannot be distinguished from ventricular tachycardia

Question 47

Exercise-associated hypotension may also be seen in patients with

Answer 47

Cardiomyopathy LV outflow tract obstruction Enhanced vagal tone Hypovolemia Antihypertensive medications Arrhythmias

Question 48

This response occurs in patients who are anxious about the exercise study and begin exercise with a somewhat elevated systolic pressure.

Answer 48

Pseudo–exercise-induced hypotension

Question 49

A normal rise in systolic BP is approximately _______________ increase.

Answer 49

10 mm Hg per MET

Question 50

A blunted BP rise during exercise may be due to

Answer 50

Cardioactive medications Underlying heart conditions that limit the normal increase in cardiac output during exercise

Question 51

Diagnostic value of ST-segment depression has a sensitivity and specificity of ________ and ________

Answer 51

60% to 70% 70% to 80%

Question 52

The usual criterion of ST depression applied to raw data is 1 mm or greater or 0.1 mV or greater of ____________ ST-segment depression in three consecutive beats.

Answer 52

Horizontal or downsloping (i.e., <0.5 mV/sec)

Question 53

This assumes that the _________ (not the TP segment) is used as the isoelectric reference and that the point of STsegment measurement is _______ after the J point.

Answer 53

PQ point 60 to 80 milliseconds

Question 54

The ____ criterion is used at HR higher than 130 beats/min.

Answer 54

60-millisecond post–J point

Question 55

Unlike ST-segment elevation, exercise-induced ST-segment depression _______ to a precise region or vascular bed.

Answer 55

Does not localize ischemia

Question 56

The ________ (especially lead V5) are the best for defining positive responses.

Answer 56

Lateral precordial leads

Question 57

True or False Positive responses are occasionally limited to the recovery period, and these have equal significance to changes that occur at peak exercise

Answer 57

True

Question 58

True Positive changes during exercise that resolve within 1 minute of recovery are associated with a favorable prognosis and low downstream diagnostic test yield.

Question 59

True or False Early-recovery ST changes are associated with significantly smaller summed stress scores on myocardial perfusion imaging and a lower prevalence of CAD.

Answer 59

True

Question 60

Rapidly upsloping ST depression that resolves quickly is rarely _______ and _______ than horizontal or downsloping ST depression.

Answer 60

a true positive response and is less specific

Question 61

Lead ______ elevation 1-mm or greater may be a significant predictor of left main CAD, proximal left anterior descending (LAD) artery disease, or at least multivessel CAD.

Answer 61

aVR ST elevation

Question 62

The usual criterion to ST elevation applied to raw data is _______ in three consecutive beats.

Answer 62

1 mm or greater or 0.1 mV of STsegment elevation above the PQ point at 60 milliseconds after the J point

Question 63

ST-segment elevation __________ to a particular vascular region and thus, coronary angiography is an appropriate next step

Answer 63

Precisely localizes the transmural ischemia

Question 64

When pathologic Q waves are present, ST-segment elevation is usually indicative of an _________ or ________. Ischemia may be involved in this process, and myocardial perfusion imaging is generally required to determine this.

Answer 64

LV aneurysm or significant wall motion change

Question 65

______ occurring during exercise or recovery increase the likelihood of future cardiac death.

Answer 65

Ventricular ectopic beats

Question 66

___________ are not predictive of ischemia or any cardiovascular endpoint. However, they may be a marker for the later occurrence of AF or supraVT

Answer 66

Exercise-induced supraventricular arrhythmias

Question 67

The principal issue with digitalis has been _______ and _______

Answer 67

False positive results and reduced specificity Sensitivity is not affected Therefore, a negative ST-segment response with digitalis is still reliable. For most patients taking digitalis, **stress imaging** is appropriate as an initial test if the goal of the test is to assess for myocardial ischemia.

Question 68

Identification of ischemic heart disease in women can be a diagnostic challenge because of several factors:

Answer 68

Lower prevalence of obstructive CAD in women younger than 65 More atypical manifestations of ischemic symptoms More frequent resting ST changes

Question 69

Exercise testing has similar diagnostic characteristics in women with an _________ as it does for men

Answer 69

Intermediate probability of CAD

Question 70

Electrocardiogram and Non-Electrocardiogram Variables Associated with an Elevated Ischemic Heart Disease Risk from Exercise Testing in Women

Answer 70

Exercise capacity: <5 METs <100% age-predicted METs = 14.7–(0.13 × age)

Question 71

Exercise testing also has a role in patients with valvular heart disease who want to participate in _____________.

Answer 71

Competitive athletic activity

Question 72

Exercise testing is combined with echocardiography to assess ________

Answer 72

Structural and physiologic responses This is the preferred approach in evaluating patients with mitral stenosis and disparate clinical and resting echocardiographic data, such as severe stenosis without symptoms or symptoms with mild to moderate stenosis.

Question 73

The only valve lesion in which the simple exercise ECG still has a significant role in management is ________

Answer 73

Aortic stenosis

Question 74

Exercise testing is absolutely c cated in patients with ______________

Answer 74

Symptomatic severe valvular aortic stenosis

Question 75

Exercise testing may be considered for patients with AS

Answer 75

Asymptomatic patients with severe acquired valvular aortic stenosis Moderate stenosis but suspected symptoms

Question 76

The purpose of exercise testing in this setting is to induce either _______ or an abnormal BP response, which most studies define as a lack of increase or ___________ in systolic BP

Answer 76

Symptoms ≤20 mm Hg increase Exercise testing in this scenario should be performed only in those with no reported symptoms or with symptoms that are equivocal at worst, such that aortic valve surgery is not indicated on that basis.

Question 77

In young or adolescent patients with congenital aortic valve stenosis that is moderate to severe Exercise testing is done to provide advice for patients wanting to ________ as well as to evaluate asymptomatic patients with severe stenosis to

Answer 77

Participate in athletic activities Assess the BP response and exercise tolerance

Question 78

Exercise test in HCM carries a class I recommendation for assessing ________ using exercise echocardiography and for assessing patients with nonobstructive HCM for _______ using CPX; class IIa for determination of ________ and _______

Answer 78

Dynamic outflow obstruction Possible cardiac transplantation f\functional capacity and for risk stratification

Question 79

Exercise testing in patients with HCM has clinical value in three clinical situations:

Answer 79

(1) defining the presence of exercise-induced outflow tract obstruction with Doppler echocardiography in patients with no gradient at rest (2) identifying patients with coexistent CAD (3) detecting patients with the high-risk indicator of an abnormal BP response

Question 80

An _______ during upright treadmill exercise is a risk factor for SCD in patients with HCM

Answer 80

Abnormal BP response It is of greater predictive value in patients younger than 50 years. An abnormal BP response is defined as either an initial increase in systolic pressure with a subsequent fall greater than 20 mm Hg, or a continuous fall from the start of exercise greater than 20 mm Hg.

Question 81

The specific congenital conditions where the exercise-ECG has a role include

Answer 81

Repaired and unrepaired aortic coarctation Repaired tetralogy of Fallot Surgically and congenitally corrected transposition of the great arteries Coronary artery anomalies.

Question 82

Indications for exercise testing in AF:

Answer 82

When myocardial ischemia is suspected and initiation of type IC antiarrhythmic drug therapy is being considered Assessing the adequacy of HR control across a full spectrum of activity in patients with persistent or permanent AF Exercise testing may be used to induce possible exercise-induced AF

Question 83

Exercise testing is useful to assess for exercise-induced ventricular arrhythmias in patients with ventricular arrhythmia symptoms associated with

Answer 83

Exertion Suspected ischemic heart disease Catecholaminergic polymorphic ventricular tachycardia

Question 84

In symptomatic and asymptomatic patients with preexcitation, the findings of ________ during exercise testing in sinus rhythm is useful to identify patients at low risk of rapid conduction over the pathway

Answer 84

Abrupt loss of conduction over a manifest pathway

Question 85

Catecholaminergic polymorphic VT generally appears in HRs __________ and begins with polymorphic ventricular premature beats progressing to nonsustained VT and eventually to bidirectional or polymorphic VT

Answer 85

above 120 to 130 beats/min The purpose of the exercise test, therefore, is to achieve a diagnosis and determine the patient’s response to treatment, namely, beta blockade.

Question 86

Changes in the QT interval with exercise can be useful in identifying and stratifying patients with LQTS Effects of exercise testing in LQTS1 LQTS2 LQTS3

Answer 86

Further prolongation of (or failure to shorten) an already prolonged QT interval with exercise is typical of LQT1 LQT2 has normal shortening LQT3 has supranormal shortening of the QT interval with exercise

Question 87

Exercise testing has no significant role in the management of these patients

Answer 87

Arrhythmogenic Right Ventricular Cardiomyopathy

Question 88

In patients without further chest pain and no objective evidence of ischemia, an exercise test can be performed ______ of observation.

Answer 88

After 8 to 12 hours

Question 89

Intensity of dynamic aerobic exercise is usually determined from the results of a pretraining exercise test by using either of two methods:

Answer 89

40% to 80% of peak exercise capacity using the HR reserve method HR at 40% to 80% of the measured peak VO2

Question 90

A simpler approach is to have individuals exercise at _________

Answer 90

70% to 85% of their maximal measured HR

Question 91

The goal duration of exercise at the prescribed intensity is generally ________ per session at a frequency of ________ per week.

Answer 91

20 to 60 minutes 3 to 5 days

Question 92

Exercise testing can be performed in patients with PAD to establish further the diagnosis by noninvasive techniques, particularly in patients with _______

Answer 92

Calf pain and borderline ankle-brachial indices (ABIs: 0.91 to 1.0)

Question 93

Several diagnostic criteria to diagnosed PAD after exercise testing have been proposed and include

Answer 93

Greater than a 5% drop in post-exercise ABI from resting levels Postexercise ABI lower than 0.9 Greater than a 30 mm Hg drop in systolic BP at the ankle Recovery time to baseline ABI longer than 3 minutes

Question 94

Class I indications for exercise testing for PAD

Answer 94

• Patients with ABI 0.91–0.99 may possibly have PAD, and should undergo exercise ABI if the clinical suspicion of PAD is significant. • Patients with exertional non-joint-related leg symptoms and normal or borderline resting ABI (>0.90 and ≤1.4) should undergo exercise treadmill ABI testing to evaluate for PAD.