Chapter 15 Flashcards
1
Q
product of cardiac output and oxygen extraction at the periphery
A
total-body oxygen uptake (VO2)
2
Q
What does the Fick equation describe?
A
Resting VO2 = CO x A-VO2 difference
3
Q
What does 1 MET equal in terms of oxygen uptake?
A
3.5 ml O2/kg of BW/min
resting energy expenditure
4
Q
What is VO2 Max?
A
Peak O2 uptake during the highest level of dynamic exercise
cannot be exceeded despite increases in work rate
5
Q
What factors are related to VO2 Max?
A
- Age
- Sex
- Heredity
- Exercise habits
- Cardiovascular status
6
Q
How much can cardiac output increase in the upright position?
A
4-6 times resting levels
Result of a twofold to threefold increase in heart rate (HR) from resting levels and an increase in stroke volume
7
Q
What is the maximum increase in heart rate during exercise?
A
2x-3x increase from resting levels
8
Q
At what percentage of VO2 Max does stroke volume plateau?
A
50-60%
9
Q
What is the max arteriovenous O2 difference limit?
A
15-17 ml O2/100 ml blood
10
Q
What are the determinants of myocardial O2 demand?
A
- HR
- BP
- LV Contractility
- LV wall stress
11
Q
VO2 attained during symptom-limited, maximum tolerated exercise
A
VO2 peak
12
Q
What does the Rate-pressure product indicate?
A
product of HR and systolic BP
Reliable index of myocardial oxygen demand
13
Q
What type of exercise elicits higher HR and BP responses?
A
Dynamic arm exercise
14
Q
How does resistance exercise affect cardiac output?
A
CO rises primarily due to an increase in HR
15
Q
What happens to vascular resistance during resistance exercise?
A
Elevated peripheral resistance due to muscle contraction
16
Q
What is the effect of resistance exercise on blood pressure?
A
Elevates both systolic and diastolic BP
17
Q
What happens to coronary blood flow during exercise?
A
Increases in response to neurohumoral stimulation
18
Q
What is the effect of 50-70% stenosis on coronary blood flow?
A
Impair peak reactive hyperemia
90% or greater stenosis will reduce resting flow
19
Q
What should patients without known CAD do before an exercise test?
A
Withhold cardioactive medications
20
Q
What is the primary outcome of the six-minute walk test?
A
Distance walked
21
Q
What does cardiopulmonary exercise testing (CPX) measure?
A
Ventilatory gas exchange analysis during exercise
22
Q
What is the hypertensive systolic pressure response threshold for men?
A
> 210 mmHg
23
Q
What is exercise-induced hypotension?
A
SBP during exercise falling below resting SBP
24
Q
What is the normal response of QRS duration during exercise?
A
Shortening of QRS, PR, and QT intervals
25
What does a ventricular ectopic activity indicate?
Increased likelihood of future cardiac death
26
What does the ST/heart rate slope method analyze?
ST-segment depression as a function of HR
27
What effect does digitalis have on exercise testing?
Can cause false positives, reducing specificity
28
What is chronotropic incompetence?
Failure to achieve a chronotropic index higher than 80%
Inability of the heart to increase its rate to meet demand
## Footnote
[(HRmax−HRrest)/(220−Age−HRrest)]×100
Criteria for assessing chronotropic incompetence in patients with atrial fibrillation (AF) have not been established
29
What is the formula to calculate the ST/HR index?
Divide the maximum ST-segment depression in microvolts by the difference in resting and peak HR.
30
What is the criterion for abnormality in the ST/HR index?
1.6 μV/beat/min.
31
How does digitalis affect exercise testing?
It can cause false positives and reduced specificity but does not affect sensitivity.
32
What is the recommended initial test for patients taking digitalis?
Stress imaging to assess for myocardial ischemia.
33
What effect do beta blockers have on exercise testing?
They reduce rate-pressure product and adversely affect sensitivity and NPV.
34
When should beta blockers ideally be withheld for exercise testing?
In patients without established CAD to allow an adequate HR response.
35
What is the standard exercise test cut point for ST-segment depression?
0.1 mV (1 mm) of horizontal or downsloping ST-segment depression in three consecutive beats.
## Footnote
>The normal and rapid upsloping ST-segment responses are normal responses to exercise= J point depression with rapid upsloping ST segments is a common response in an older
>slow upsloping ST-segment pattern may suggest an ischemic response in patients with known CAD or those with a high pretest clinical risk of CAD
>
36
What is the sensitivity and specificity of the standard exercise test cut point?
Sensitivity: 68%, Specificity: 77.
37
What factors contribute to the prognostic value in women during exercise testing?
* Peak exercise capacity (METs) * Chronotropic response * HRR * BP response
38
What is the strongest predictor of prognosis in exercise testing?
Functional capacity.
39
What is the Duke Treadmill Prognostic Score used for?
Assessing exercise time, ST-segment deviation, and angina score.
40
What is the mortality risk associated with a Fitness Risk Score of >100?
98% mortality.
41
What are the recommended time frames for exercise testing post-MI?
* 4-7 days after discharge: submaximal * 14-21 days: symptom limited * 3-6 weeks: symptom limited
42
What is the role of exercise testing in patients with severe valvular aortic stenosis?
It is contraindicated in symptomatic patients; asymptomatic patients may be tested under specific conditions.
43
In what scenario is exercise testing useful for asymptomatic severe aortic stenosis?
To induce symptoms or abnormal BP response.
44
What test can be used in frail or elderly patients with severe mitral regurgitation?
6-minute walk test.
45
What does the 2020 ACC/AHA guideline state about exercise testing in HCM?
It carries a class I recommendation for assessing dynamic outflow obstruction.
46
What are the criteria for abnormal BP response during exercise in patients with HCM?
* Initial increase in systolic pressure with a subsequent fall > 20mmHg * Continuous fall > 20mmHg from the start of exercise.
47
What is the role of exercise testing in adult congenital heart disease?
Baseline evaluation and serial follow-up for response to treatment.
48
What is a key diagnostic criterion for PAD during post-exercise ABI testing (4)?
>5% drop in post-exercise ABI from resting levels
post-exercise 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
49
What is the definition of functional disability in exercise testing?
Inability to attain a directly measured peak Vo2 of 15mL/kg/min.
50
What are the two diagnostic sensitivities for exercise ECG testing in T2DM patients?
Sensitivity: 60%, Specificity: 80%.
51
What should be the next diagnostic for diabetic individuals with abnormal resting ECG?
Pharmacologic stress echocardiography or nuclear imaging.
52
Exercise capacity is most accurately measured by
CPX
53
How to estimate predicted METs?
Men
Women
Men PredictedMETs=18−(0.15×Age)
Women PredictedMETs=14.7−(0.13×Age)
54
Abnormal HR recovery (HRR)
<12 beats/min decrement after 1 minute with post-exercise slow walking cool-down
<18 beats/min after 1 minute with immediate cessation of movement into either the supine or sitting position
<22 beats/min after 2 minutes
## Footnote
associated with an increase in all-cause mortality in both asymptomatic individuals and patients with established heart disease
55
Indications for cardiopulmonary exercise testing (CPX):
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.
* For differentiating cardiac from pulmonary limitations as a cause of exercise-induced dyspnea or impaired exercise capacity when the cause is uncertain.
* 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.
56
Indications for Terminating the Exercise Test (8):
* 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
57
Class I indications for Exercise Testing in Peripheral Artery Disease (2):
* 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.
58
Criteria for slow upsloping ST-segment depression:
J point and ST80 depression of 0.15 mV or more and ST-segment slope of more than 1.0 mV/sec
59
Classic criteria for myocardial ischemia
horizontal ST-segment depression observed when both the J point and ST80 depression are 0.1 mV or more and the ST-segment slope is within the range of 1.0 mV/sec
60
Downsloping ST-segment depression:
J point and ST80 depression are 0.1 mV and the ST-segment slope is −1.0 mV/sec
## Footnote
ST segment measured 80 milliseconds after the J point.
61
ST-segment elevation in a non–Q wave noninfarct lead
J point and ST60 are 1.0 mV or higher
## Footnote
>represents a severe ischemic response
>ST-segment elevation in an infarct territory (Q wave lead) indicates a severe wall motion abnormality and, in most cases, is not considered an ischemic response
62
Isoelectric reference in interpreting ECG
PQ point (not the TP segment)
## Footnote
>ST-segment measurement is 60 to 80 milliseconds after the J point
>60-millisecond post–J point criterion is used at HR higher than 130 beats/min
63
best lead for defining positive responses
V5
## Footnote
Isolated inferior ST depression is frequently falsely abnormal because of the influence of atrial repolarization in these leads
64
TRUE/FALSE
ST-segment depression that is slowly upsloping (0.5 to 1.0 mV/sec) may be considered normal
FALSE
It may be considered abnormal,
especially if it occurs at low workloads
65
TRUE/FALSE
When EI-LBBB occurs at HRs higher than 125 beats/min, this finding is not likely to reflect underlying CAD.
TRUE
## Footnote
EI-RBBB from one recent large Veterans Affairs series correlated with age, and was not associated with added incremental risk
66
A normal rise in systolic BP is approximately ____mm Hg per MET increase.
10 mmHg
67
All of the following are major physiologic responses during exercise except:
A. Sympathetic outflow increases while parasympathetic outflow decreases
B. Increased cardiac output, heart rate, oxygen demand, and peripheral resistance.
C. Constriction of renal and splanchnic arterioles as well as peripheral veins
D. Increased arteriovenous difference or total body oxygen extraction
B
68
The following are true of the difference between acute endurance & resistance exercises except:
A. Acute endurance mainly decreases venous return while resistance exercises increases it.
B. Rise in cardiac output is smaller in resistance exercises compared with acute endurance exercises.
C. Dynamic arm exercises elicits higher heart rate and blood pressure responses vs dynamic leg exercises.
D. Both exercises are accompanied by left ventricular hypertrophy
A
69
Relative contraindication to exercise testing
A. Known left anterior descending artery stenosis
B. Tachyarrhythmia with uncontrolled ventricular rates
C. Acute myocardial infarction within 2 days
D. Acute myocarditis or pericarditis
B
70
The strong predictor of mortality and nonfatal cardiovascular outcomes in both men and women with and without CAD
A. Peak heart rate
B. Chronotropic index
C. Functional capacity
D. Systolic pressure
C
71
True of the 6-minute walk test protocol
A. should be performed indoors, along a long, flat, straight, enclosed corridor with a hard surface that is seldom traveled
B. The walking course must be 50-100m in length.
C. Position the patient at the starting line, you should also stand near the starting line and should walk together with patient.
D. None of the above
72
Chronotropic incompetence is defined as
A. Failure to achieve chronotropic index higher than 75%
B. Failure to achieve chronotropic index higher than 80%
C. Failure to achieve chronotropic index and peak heart rate higher than 65%
D. Failure to achieve chronotropic index and peak heart rate higher than 70
B
73
Criteria for ST elevation during ecg exercise test is
A. 2mm or greater or 0.2mV of ST elevation above the PQ point at 60ms after the J point in 3 consecutive beats
B. 2mm or greater or 0.2mV of ST elevation above the PQ point at 60ms after the J point in 2 consecutive beats
C. 1mm or greater or 0.1mV of ST elevation above the PQ point at 60ms after the J point in 2 consecutive beats
D. 1mm or greater or 0.1mV of ST elevation above the PQ point at 60ms after the J point in 3 consecutive beats
D
