Transcript Exercise Treadmill Testing

Exercise Treadmill Testing
Chris Place, MD
December 2, 2004
Overview
• Basic EKG Review
• Introduction to Treadmill Test
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Indications and Safety
Equipment and Protocols
Exercise End Points
Basics of Interpretation of the Exercise Test
• Exercise Testing to Diagnose Obstructive
Coronary Artery Disease
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Rationale and Guidelines
Pretest Probability
ST-Segment Interpretation
Confounders of Stress ECG Interpretation
• Result Reporting
Basic EKG Review
Simple Method of EKG Interpretation
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•
•
•
•
Rate
Rhythm
Axis
Hypertrophy
Infarction and Ischemia
Rate
Rhythm
• Identify basic rhythm…
– …then scan entire tracing for pauses,
premature beats, irregularity, and abnormal
waves.
• Always:
– Check for:
• P before each QRS.
• QRS after each P.
Axis
Hypertrophy
Infarction and Ischemia
Normal EKG
Atrial Fibrillation with Rapid
Ventricular Response
Inferior Acute MI and RBBB
Anterior Acute MI
Left Ventricular Hypertrophy
Ventricular Fibrillation
Overview
• Basic EKG Review
• Introduction to Treadmill Test
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–
–
–
Indications and Safety
Equipment and Protocols
Exercise End Points
Basics of Interpretation of the Exercise Test
• Exercise Testing to Diagnose Obstructive Coronary
Artery Disease
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–
–
–
Rationale and Guidelines
Pretest Probability
ST-Segment Interpretation
Confounders of Stress ECG Interpretation
• Result Reporting
Indications and Safety
• Generally a safe procedure, but both myocardial
infarction and death have been reported and can be
expected to occur at a rate of up to 1 per 2500 tests.
• Good clinical judgment should therefore be used in
deciding which patients should undergo exercise testing.
• Exercise testing should be supervised by an
appropriately trained physician.
• The electrocardiogram (ECG), heart rate, and blood
pressure should be monitored carefully and recorded
during each stage of exercise and during ST-segment
abnormalities and chest pain.
Equipment and Protocols
• Both treadmill and cycle ergometer devices are
available for exercise testing.
• Much of the published data are based on the
Bruce protocol, there are clear advantages to
customizing the protocol to the individual patient
to allow 6 to 12 minutes of exercise.
• Exercise capacity should be reported
in estimated metabolic equivalents
(METs) of exercise.
Exercise Endpoints
• Commonly terminated when subjects
reach an arbitrary percentage of predicted
maximum heart rate.
• Other end points (summarized next slide)
are strongly preferred.
• The use of rating of perceived exertion
scales, such as the Borg scale is often
helpful in assessment of patient fatigue.
The Modified Borg Scale
SCALE
SEVERITY
0
No Breathlessness* At All
0.5
Very Very Slight (Just Noticeable)
1
Very Slight
2
Slight Breathlessness
3
Moderate
4
Somewhat Severe
5
Severe Breathlessness
6
7
Very Severe Breathlessness
8
9
Very Very Severe (Almost Maximum)
10
Maximum
Basics of Interpretation of
the Exercise Treadmill Test
• Interpretation of the exercise test should include exercise
capacity and clinical, hemodynamic, and
electrocardiographic response.
• The occurrence of ischemic chest pain consistent with
angina is important, particularly if it forces termination of
the test.
• The most important electrocardiographic findings are ST
depression and elevation.
• Positive exercise test result is greater than or equal to 1
mm of horizontal or downsloping ST-segment depression
or elevation for at least 60 to 80 milliseconds (ms) after
the end of the QRS complex
Overview
• Basic EKG Review
• Introduction to Treadmill Test
–
–
–
–
Indications and Safety
Equipment and Protocols
Exercise End Points
Basics of Interpretation of the Exercise Test
• Exercise Testing to Diagnose Obstructive Coronary
Artery Disease
–
–
–
–
Rationale and Guidelines
Pretest Probability
ST-Segment Interpretation
Confounders of Stress ECG Interpretation
• Result Reporting
Rationale for Using ETT to
Diagnose Obstructive CAD
• Most predictive clinical finding is a history of chest pain
or discomfort.
• Myocardial ischemia is the most important cause of
chest pain and is most commonly a consequence of
underlying coronary disease.
• CAD that has not resulted in sufficient luminal occlusion
to cause ischemia during stress can still lead to ischemic
events through spasm, plaque rupture, and thrombosis,
but most catastrophic events are associated with
extensive atherosclerosis.
• These nonobstructive lesions explain some of the events
that occur after a normal exercise test.
• Although the coronary angiogram has obvious
limitations, angiographic lesions remain the clinical gold
standard.
The ACC/AHA Guidelines for the Diagnostic
Use of the Standard Exercise Test
 Class I (Definitely appropriate) - Adult males
or females (including RBBB or < 1mm resting ST
depression) with an intermediate pre-test
probability of coronary artery disease based on
gender, age and symptoms (specific exceptions
are noted under Class II and III below).
 Class IIa (Probably appropriate) - Patients with
vasospastic angina.
The ACC/AHA Guidelines for the Diagnostic
Use of the Standard Exercise Test
• Class IIb (maybe appropriate)
– Patients with a high pretest probability of
CAD by age, symptoms, and gender.
– Patients with a low pretest probability of CAD
by age, symptoms, and gender.
– Patients with less than 1 mm of baseline ST
depression and taking digoxin.
– Patients with electrocardiographic criteria for
left ventricular hypertrophy (LVH) and less
than 1 mm of baseline ST depression.
The ACC/AHA Guidelines for the Diagnostic
Use of the Standard Exercise Test, cont’d
Class III (Not appropriate) -
1. To use the ST segment response in the diagnosis of coronary
artery disease in patients who demonstrate the following baseline
ECG abnormalities:
pre-excitation (WPW) syndrome;
electronically paced ventricular rhythm;
more than one millimeter of resting ST depression;
LBBB
2. To use the ST segment response in the
diagnosis of coronary artery disease in
MI patients
Pretest Probability
• Based on the patient's history (including age, gender, and
chest pain characteristics), physical examination and initial
testing, and the clinician's experience with this type of
problem.
• Typical or definite angina makes the pretest probability of
disease so high that the test result does not dramatically
change the probability.
• Atypical or probable angina in a 50-year-old man or a 60year-old woman is associated with approximately a 50%
probability of CAD.
• Diagnostic testing is most valuable in this intermediate
pretest probability category, because the test result has the
largest potential effect on diagnostic outcome.
• Typical or definite angina can be defined as 1) substernal
chest pain or discomfort that is 2) provoked by exertion or
emotional stress and 3) relieved by rest and/or nitroglycerin.
Pre Test Probability of Coronary Disease by
Symptoms, Gender and Age
Age
Gender
Typical/Definite
Angina Pectoris
Atypical/Probable
Angina Pectoris
NonAnginal
Chest Pain
Asymptomatic
30-39
30-39
Males
Intermediate
Intermediate
low (<10%)
Very low (<5%)
Females
Intermediate
Very Low (<5%)
Very low
Very low
40-49
Males
High (>90%)
Intermediate
Intermediate
low
40-49
Females
Intermediate
Low
Very low
Very low
50-59
Males
High (>90%)
Intermediate
Intermediate
Low
50-59
Females
Intermediate
Intermediate
Low
Very low
60-69
Males
High
Intermediate
Intermediate
Low
60-69
Females
High
Intermediate
Intermediate
Low
High = >90%
Intermediate = 10-90%
Very Low = <5%
Low = <10%
ST Segment Interpretation
• Computer summaries can help find
possible areas of ischemia – then review
raw data carefully!
• Determine PQ junction, J point, ST80, and
estimate slope
• Elevation
• Depression
– Upsloping
– Horizontal
– Downsloping
Magnified ischemic exercise-induced ECG pattern. Three consecutive complexes with
a relatively stable baseline are selected. The PQ junction (1) and J point (2) are
determined; the ST 80 (3) is determined at 80 msec after the J point. In this example,
average J point displacement is 0.2 mV (2 mm) and ST 80 is 0.24 mV (2.4 mm). The
average slope measurement from the J point to ST 80 is –1.1 mV/sec.
Normal
Rapid
Upsloping
Minor ST
Depression
Slow
Upsloping
Horizontal
Downsloping
Elevation (non
Q lead)
Elevation (Q
wave lead)
Upsloping
J point depression of 2 to 3
mm in leads V4 to V6 with
rapid upsloping ST
segments depressed
approximately 1 mm 80
msec after the J point. The
ST segment slope in leads
V4 and V5 is 3.0 mV/sec.
This response should not
be considered abnormal.
• In lead V4 , the
exercise ECG result
is abnormal early in
the test, reaching
0.3 mV (3 mm) of
horizontal ST
segment depression
at the end of
exercise.
• Consistent with a
severe ischemic
response.
•The J point at peak
exertion is depressed 2.5
mm, the ST segment slope
is 1.5 mV/sec, and the ST
segment level at 80 msec
after the J point is
depressed 1.6 mm.
•This “slow upsloping” ST
segment at peak exercise
indicates an ischemic
pattern in patients with a
high coronary disease
prevalence pretest.
•A typical ischemic pattern
is seen at 3 minutes of the
recovery phase when the
ST segment is horizontal
and 5 minutes after exertion
when the ST segment is
downsloping.
•Becomes abnormal at
9:30 minutes (horizontal
arrow right) of a 12minute exercise test and
resolves in the immediate
recovery phase.
•This ECG pattern in
which the ST segment
becomes abnormal only
at high exercise
workloads and returns to
baseline in the immediate
recovery phase may
indicate a false-positive
result in an asymptomatic
individual without
atherosclerotic risk
factors.
•A 48-year-old man with several
atherosclerotic risk factors and a
normal rest ECG result developed
marked ST segment elevation (4 mm
[arrows]) in leads V2 and V3 with
lesser degrees of ST segment
elevation in leads V1 and V4 and J
point depression with upsloping ST
segments in lead II, associated with
angina.
•This type of ECG pattern is usually
associated with a full-thickness,
reversible myocardial perfusion defect
in the corresponding left ventricular
myocardial segments and high-grade
intraluminal narrowing at coronary
angiography. Rarely, coronary
vasospasm produces this result in the
absence of significant intraluminal
atherosclerotic narrowing.(
Confounders of Exercise Treadmill Test Interpretation
•
Digoxin
– Produces an abnormal ST-segment response to exercise. This abnormal ST
depression occurs in 25% to 40% of healthy subjects studied and is directly
related to age.
•
Left Ventricular Hypertrophy
– Decreased specificity of exercise testing, but sensitivity is unaffected. Therefore,
a standard exercise test may still be the first test, with referrals for additional
tests only indicated in patients with an abnormal test result.
•
Resting ST Depression
– Resting ST-segment depression has been identified as a marker for adverse
cardiac events in patients with and without known CAD.
•
Left Bundle-Branch Block
– Exercise-induced ST depression usually occurs with left bundle-branch block and
has no association with ischemia. Even up to 1 cm of ST depression can occur in
healthy normal subjects. There is no level of ST-segment depression that confers
diagnostic significance in left bundle-branch block.
•
Right Bundle-Branch Block
– The presence of right bundle-branch block does not appear to reduce the
sensitivity, specificity, or predictive value of the stress ECG for the diagnosis of
ischemia.
•
Beta Blocker Therapy
– For routine exercise testing, it appears unnecessary for physicians to accept the
risk of stopping beta-blockers before testing when a patient exhibits possible
symptoms of ischemia or has hypertension. However, exercise testing in patients
taking beta-blockers may have reduced diagnostic or prognostic value because
of inadequate heart rate response.
Overview
• Basic EKG Review
• Introduction to Treadmill Test
–
–
–
–
Indications and Safety
Equipment and Protocols
Exercise End Points
Basics of Interpretation of the Exercise Test
• Exercise Testing to Diagnose Obstructive Coronary
Artery Disease
–
–
–
–
Rationale and Guidelines
Pretest Probability
ST-Segment Interpretation
Confounders of Stress ECG Interpretation
• Result Reporting
Comparison of Tests for
Diagnosis of CAD
Grouping
Standard ET
 ET Scores
 Score Strategy
Thallium Scint
SPECT
Adenosine SPECT
Exercise ECHO
Dobutamine ECHO
Dobutamine Scint
Electron Beam
Tomography (EBCT)
# of
Total #
Studies Patients
147
24,047
24
11,788
2
>1000
59
6,038
16+14 5,272
10+4
2,137
58
5,000
5
<1000
20
1014
16
3,683
Sens Spec Predictive
Accuracy
68% 77%
73%
85%
85%
88%
89%
84%
88%
88%
60%
92%
85%
72%
80%
75%
84%
74%
70%
80%
88%
85%
80%
85%
80%
86%
81%
65%
Results Reporting
Hope Medical Group
Exercise Treadmill Test
Results Report – rev. 11/04
Patient Name:
Chart Number:
Reason for Test:
________________________________________________________________________
Digoxin? _______
Beta blocker? ________
Resting EKG interpretation:
________________________________________________________________________
________________________________________________________________________
LVH? ___________
LBBB? __________
RBBB? ___________
Resting ST Depression? _________
Cardiac Risk Factors (circle)
Age
Gender
Diabetes
HTN
Hypercholesterolemia
Smoker
Sedentary/Obese
Total Number:
Estimate pretest probability – use table for reference (very low, low, intermediate, high, very high):
_______________________________________________________________________
Reason for test if pretest probability not intermediate:
_______________________________________________________________________
Date of Test:
1.
2.
3.
4.
Exercise Capacity
METS achieved: _______________
Results Reporting –
Minutes exercised: _______________
Clinical response to exercise
Chest pain during test? ___________
Chest pain reason for stopping test? __________
Perceived exertion scale (BORG scale reached – 6 to 20): _________
Reason for stopping test:_____________
Electrocardiographic response to exercise
ST elevation (yes/no) ? ____________
ST depression (yes/no)? ____________
(positive = 1 mm of horizontal or downsloping ST-segment depression or
elevation for at least 60 to 80 milliseconds (ms) after the end of the QRS
complex)
What leads? ___________
ST quality (upsloping, horizontal,
downsloping):_______________
ST depression amount (mm): ___________
Dysrhythmia? _____________
Other:
____________________________________________________
Hemodynamic response to exercise
Systolic BP response: ______________
Diastolic BP response: ______________
Maximum heart rate achieved: ________________
2 minute heart rate recovery (should be at least 22 bpm by 2
minutes): ______________
Page 2
What is a MET?
 Metabolic Equivalent Term
1 MET = "Basal" aerobic oxygen
consumption to stay alive = 3.5 ml O2
/Kg/min
 Actually differs with thyroid status, post
exercise, obesity, disease states
Key MET Values
 1 MET = "Basal" = 3.5 ml O2 /Kg/min
 2 METs = 2 mph on level
 4 METs = 4 mph on level
 < 5METs = Poor prognosis if < 65;
Key MET Values (part 2)


10 METs = As good a prognosis with
medical therapy as CABG
13 METs = Excellent prognosis, regardless
of other exercise responses

16 METs = Aerobic master athlete

20 METs = Aerobic athlete
Calculation of METs on the Treadmill
METs = Speed x [0.1 + (Grade x 1.8)] + 3.5
3.5
Calculated automatically by Device!
Note: Speed in meters/minute
conversion = MPH x 26.8
Grade expressed as a fraction
Results Reporting – Page 3
5. Duke treadmill scores (see nomogram or use calculator):
5-year survival _______
Average annual mortality __________
6. VA treadmill score: _________
7. Final conclusions and recommendation for follow-up:
______________________________________________________________
______________________________________________________________
______________________________________________________________
Duke treadmill score = duration of exercise in minutes on the
Bruce protocol
- (minus) 5x maximal mm ST deviation
- (minus) 4x treadmill angina index
Treadmill Angina Index:
0 if no angina.
1 if non-limiting angina.
2 if limiting angina.
High Risk = treadmill score < -10
79% 4-year survival
Moderate Risk = treadmill score -10 to +4
95% 4-year survival
Low Risk = treadmill score >+5
99% 4-year survival
Duke Nomogram for 2 mm depression,
non-limiting chest pain at 5 METS.
Variable
Maximal Heart Rate
Circle response
Less than 100 bpm = 30
100 to 129 bpm = 24
130 to 159 bpm =18
160 to 189 bpm =12
190 to 220 bpm =6
Exercise ST Depression
1-2mm =15
> 2mm =25
Age
>55 yrs =20
Sum
Males
Choose
only one
per
group
40 to 55 yrs = 12
Angina History
Definite/Typical = 5
Probable/atypical =3
Non-cardiac pain =1
Hypercholesterolemia?
Yes=5
Diabetes?
Yes=5
Exercise test
induced Angina
Occurred =3
Reason for stopping =5
Total Score:
<40=low prob
40-60=
intermediate
probability
>60=high
probability
Variable
Maximal Heart
Rate
Circle response
Less than 100 bpm = 20
Women
100 to 129 bpm = 16
130 to 159 bpm =12
160 to 189 bpm =8
190 to 220 bpm =4
Exercise ST
Depression
Age
Sum
1-2mm =6
> 2mm =10
>65 yrs =25
Choose
only one
per
group
50 to 65 yrs = 15
Angina History
Definite/Typical = 10
Probable/atypical =6
Non-cardiac pain =2
Smoking?
Diabetes?
Exercise test
induced Angina
Estrogen Status
Yes=10
Yes=10
Occurred =9
Reason for stopping =15
Positive=-5, Negative=5
Total Score
<37=low prob
37-57=
intermediate
probability
>57=high
probability
Review
• Basic EKG Review
• Introduction to Treadmill Test
–
–
–
–
Indications and Safety
Equipment and Protocols
Exercise End Points
Basics of Interpretation of the Exercise Test
• Exercise Testing to Diagnose Obstructive Coronary
Artery Disease
–
–
–
–
Rationale and Guidelines
Pretest Probability
ST-Segment Interpretation
Confounders of Stress ECG Interpretation
• Result Reporting