Download Exercise Stress Testing

Learning Objectives
Exercise Stress
Electrocardiography
• Provide an understanding of the value of
Gerald F. Fletcher MD
Mayo Clinic Florida
• Clarify the importance of determining the
the multiple ECG and Physiological
measures that are recorded from an ECG
exercise test
exercise work capacity of a subject
• Detail the role the ECG Exercise Test has
No Disclosures
in the evaluation of the cardiac status of an
individual
Historical Perspective
Historical Perspective
Over 2000 yrs ago—
—Chinese, Romans and
ago
ago—Chinese,
Greeks used treadmills for irrigation and
construction.
—Reformers considered treading
• 1846—
1846
1846—Reformers
1818—
—Cubitt [British engineer] developed
1818
1818—Cubitt
the ““stepping
stepping wheel”
wheel”
““Treading
Treading the wheel”
wheel” for punishment was
popular in English prisons.
the wheel a cruel, inhumane and
unhealthy practice
• Edward Smith began respiratory and
metabolic testing, thus the beginning
the modern era of testing
Subject Population
ECG Exercise Testing
• Normal Healthy
• Those at risk for CVD
• Post MI
• Post PCI and CABG
• Heart Failure
• Other
• Treadmill, Bike, Arm, Arm/Leg
• ECG changes
• Symptoms
• Heart rate, rhythm, blood pressure
• Work capacity
1
Relative Costs of Testing
• $ ECG Treadmill
• $ ECHO
• $ MRI
• $ Nuclear
• $ PET
• $ CT
• $ CT Angio
1.0
Bruce Protocol
Stage
3.0
1
2
5.0
3
4
5.2
Exercise ECG Changes of Ischemia
-divergent ST depression of
• HorizontalHorizontal
Horizontal-divergent
equal to or greater than 1 mm for 80 ms
—degree, time, leads, resolution
• Important—
Important
Important—degree,
• ST elevation in infarct area of > 1 mm is
abnormal
• ST elevation with no MI likely indicates
significant proximal lesion or spasm
5
6
7
4.2
5.0
16
18
3
3
12
15
5.5
6.0
20
22
3
3
18
21
Circulation 2001; 104: 1699
ECG Exercise S-T Changes
S
S-T
• Configuration
• Time of Onset
• Double Product at Onset
• Magnitude
• Duration in Recovery
• Number of Leads
Classic
Upsloping
2.0
2.0
1.5
1.5
Froelicher VF. Exercise and The Heart.
Clinical Concepts. Chicago,
Year Book Medical Publishers, 1987
1.0
Millivolts
Millivolts
Speed Grade Duration Time
mph
%
min
min
1.7
10
3
3
2.5
12
3
6
3.4
14
3
9
0.5
Froelicher VF. Exercise and The Heart.
Clinical Concepts. Chicago,
Year Book Medical Publishers, 1987
1.0
0.5
80
msec
2
-0.2
-0.4
Abnormal
Wo
rse
2
-0.2
-0.4
al
rm
No
rma
Abno
l
-0.2 mv
2
10
Percent With Event
Strong Positive ETT
8
Ekelund et al.
The lipid research clinics
coronary primary prevention trial.
J Am Coll Cardiol 14:556, 1989
6
4
Weak Positive ETT
2
Negative ETT
0
1
2
3
4
5
6
7
8
Years of Follow Up
Blood Pressure Response
Heart Rate Response
• Systolic increases
—same or decreases
• Diastolic—
Diastolic
Diastolic—same
—[<20• Inadequate increase—
increase
[<20-30 mm]
increase—[<20-30
Consider aortic stenosis,
stenosis, severe LV
dysfunction, ischemia or medications
—systolic may
• Some CAD patients—
patients
patients—systolic
-both
• Increases linearly with work loadload
load-both
sympathetic and vagal influence
• Slope of increase influenced age, level of
conditioning, position, type of exercise and
various states of health and therapy
increase in recovery > maximal exercise
Heart Rate Recovery
• Decrease in heart rate post exercise
relates to vagal tone reactivation
• Can be abnormal in coronary artery
disease and heart failure
Arrhythmias
• Significant ventricular ectopy during and
post exercise is associated with increased
mortality
• Wave form is also important
• Atrial arrhythmias are also associated with
increased mortality
3
Conduction Changes
• Left Bundle Branch Block that occurs at
heart rate<125 bpm is often associated
with CAD
-V block may reflect
• Mobitz Type 2 AA
A-V
severe conduction problems and test
should be terminated
Changes in Physical Fitness and
All-Cause Mortality
All
All-Cause
• 9,777 asymptomatic men
• Stress test at baseline and 5 years
Results
• Those that maintained or improved
exercise capacity had lower all cause
and CV mortality
• 7.9% decrease in all cause mortality if
treadmill time increased by one MET
over 5 years
Exercise Capacity and the Risk of
Death in Women
• 5721 asymptomatic women
• History, exam, and stress ECG (Bruce)
• Exercise capacity measured in METs
-2000
• Followed 19921992
1992-2000
Circulation 2003; 108:1554-1559
4
Hazards Ratio of Death
Hazards Ratio of Death
Adjusted
Adjusted for
for Age
Age
Adjusted
Adjusted for
for Framingham
Framingham Risk
Risk Score
Score
1.9
1.9
(1.3-2.9)
(1.3-2.9)
33
22
11
22
(1.3-3.2)
(1.3-3.2)
• Largest cohort of asymptomatic
women studied
3.1
3.1
(2.1-4.8)
(2.1-4.8)
44
Exercise Capacity and the Risk
of Death in Women
11
• Longest follow up
• Confirms that exercise capacity is
1.6
1.6
(1.1-2.4)
(1.1-2.4)
11
an independent predictor of death
00
<5
<5 MET
MET
5-8
5-8 MET
MET
>8
>8 MET
MET
Circulation 2003; 108:1554-1559
Achieving an Exercise Workload
Of Greater Than 10 METS Predicts a
Very Low Risk of Inducible Ischemia
Achieving an Exercise Workload
Of Greater Than 10 METS Predicts a
Very Low Risk of Inducible Ischemia
Bourque, Beller et al
JACC 2009; 54: 538
• Prospective analysis of 1,056 patients who
had exercise MPI
• Compared exercise capacity and ischemia
RESULTS
• 974 attained >85% MPHR
• 473 [49%] achieved >10 METs
• Only 2 [0.4%] had ischemia
• Those attaining <7 METs had 18 x
more ischemia [7.0%]
RESULTS
((Con’t)
Con’
Con’t)
• Of 430 reaching >10 METs without
S
-T changes, none had >10% ischemia
S-T
• The prevalence of >10% ischemia was
was highest in those <10 METs with
with S-T changes [19%]
S
S-T
5
Conclusions
-T
• Achieving >10 METs with no SS
S-T
depression ––essentially
essentially no ischemia
-high risk patients
• In this group of intint
int-high
[31%of all], elimination of MPI could
save significant costs
Contraindications to Exercise Testing
• Unstable Angina
• Aortic Stenosis
• Uncontrolled Hypertension
• Certain Arrhythmias
• Musculoskeletal Issues
CABG Survival
• In subjects with an exercise capacity
> 10 METs
• CABG was not shown to improve
survival compared to medical therapy
Circulation 2001; 104:1710
Conclusions
• Exercise testing is a noninvasive
procedure of great value in the
cardiovascular evaluation.
• CPX is more often used in the research
setting and is more complete and precise
with pulmonary/metabolic measures
Conclusions
• ECG testing is more readily available, less
expensive and quickly performed
• The simple ECG exercise test is an
excellent means of evaluating symptoms,
work capacity, hemodynamic and ECG
endpoints
6