Transcript EXERCISE STRESS TEST

EXERCISE STRESS TEST
Physiology and Protocol,
Indications and Contraindications
DN
• Essential ET Terminology
• Performance of the E S T
• Assess Exercise Test Responses
• Interpretation Of The Exercise Stress Test
Exercise Test Terminology
• Vo2max
• METs
• Myocardial Oxygen
Consumption
Maximal Oxygen Uptake (VO2max)
• Greatest amount of oxygen an individual utilizes
with maximal exercise (ml O2 /kg/ min)
• “Gold Standard” for cardiorespiratory fitness
• Fick Equation
Vo2max = (HRmax x SVmax) x (CaO2max CvO2max)
FICK EQUATION
(220 - Age)
PaO2
Sinus Node Dysfunction
Hgb [ ]
Drugs (e.g., B - blockers)
SaO2
Diffusion
Ventilation
Perfusion
VO2max = (HRmax X SVmax) X (CaO2max - CvO2max)
Genetic Factors (Heart Size)
Conditioning Factors
Contractility/Afterload/Preload
Disease Factors
Wall Motion/Ventricular Fn, Valve Stenosis
or Regur
Skeletal Muscles
•Aerobic Enzymes
•Fiber Type
•Muscle Disease
•Cap density
MET
• Metabolic Equivalent Term
• 1 MET = "Basal" aerobic oxygen consumption to
stay alive = 3.5 ml O2 /Kg/min
• inf- thyroid status, post exercise, obesity,
disease states
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;
10 METs = prognosis with med therapy =
CABG
13 METs = Excellent prognosis
16 METs = Aerobic master athlete
Calculation of METs on the Treadmill
METs = Speed x [0.1 + (Grade x 1.8)] + 3.5
3.5
Calcul automatically by device
Speed in meters/minute
= MPH x 26.8
Grade expressed as a fraction
Myocardial (MO2)

Accurate measurement - cardiac
catheterization


Coronary Flow x Coronary (a – v)O2 diff
HR, SBP, LVEDV, CONTRACTILITY, WALL
THICKNESS
.
Myocardial Oxygen Consumption
• Indirectly measured as the “Double
Product”
• “Double Product” = HR x SBP
– A normal value is greater than 20,000 – 25,000
– < 20,000 is low heart work load
– > 29,000 indicates high heart work load
• Angina & ST↓occur at the same DP for an
individual
Types of Exercise
1.
Isometric (Static)
-weight-lifting
-pressure work for heart, limited
cardiac output
2.
Isotonic (Dynamic)
-walking, running, swimming, cycling
-Flow work for heart
-↑CO,↓ TPR
3.
Mixed
Exercise physiology
• Sympathetic activation
• Parasympathetic withdrawal
• Vasoconstriction, except in– Exercising muscles
– Cerebral circulation
– Coronary circulation
• ↑norepinephrine and renin
Exercise physiology
• ↑ventri contractility
• ↑O2 extraction(upto 3)
• ↓peripheral resistance
• ↑SBP,MBP,PP
• DBP –no significant change
• Pulm vasc bed can accommodate 6 fold CO
• CO - ↑ 4-6 times
Exercise physiology
Isotonic exercise(cardiac output)
• Early phase- SV+HR
• Late phase-HR
• peak oxygen consumption- age, sex, & training level
of the person performing
the exercise
V peak
02
(VO2max)
Oxygen
consumption
(liters/min)
Work rate
(watts)
• The plateau in peak oxygen consumption- Vo2 max
• Vo2 max is limited by
1)the ability to del O2 to sk. muscles
2) muscle oxidative capacity .
Respiration during
exercise
• dynamic exerciseventilation increases
linearly over the mild to
moderate range, then >
rapidly in intense
exercise
• workload at which
rapid ventilation
occures is called the
ventilatory breakpoint
(together with lactate
threshold)
Lactate acidifies the blood, driving off CO2 and increasing ventilatory rate
BP rise in exercise
• (SBP) ↑up to 150-170
mm Hg during
dynamic exercise;
diastolic rarely alters
• isometric - SBP may
≥250 mmHg, and DBP
can reach 180
Intense exercise 
Glycolysis>aerobic metabolism 
↑ blood lactate
Blood
lactic
acid
(mM)
Relative work rate (% V02 max)
Lactate
threshold;
endurance
estimation
Age Pred Max HR
• APMHR=220 - age in years\
• APMHR=200-1/2 age
• MHR ↓ with age
• Lower/higher than actual value(+/_12beats)
• Not used as an indicator of max exertion in
EST/ Indi to terminate test
.
Post exercise phase
• Vagal reactivation
-Imp-cardiac decceleration mech
• ↑in well trained athletes
• Blunted in CCF
ENERGY REQ
ACTIVITY
1 MET
TAKING CARE OF SELF
WALKING INDOORS
WALK AT 2-3 mph
4 METS
LIGHT WORK AROUND THE HOUSE
WALKING AT 3-4 mph
>4-<10 METS
>10 METS
CLIMB 1 FLIGHT OF STAIRS/UP HILL
WALK>4 mph, SHORT RUNNING
SCRUBBING FLOOR,MOVING
FURNITURE
RUNNING> 6-7 mph
HEAVY LABOUR
SWIMMING,FOOTBALL
Exercise Stress Testing
• Pathophysiology:
– At rest- adequate coronary blood flow
– with exercise-supply\demand mismatch -ST
segment changes
– 70-80%occlusion - detection by EST
– Sign CAD can exist with a -VE Exercise Stress Test.
Treadmill protocol
EST- stand protocols to progressively ↑ cardiovascular
work load in a uniform and reproducible way
•
•
•
•
•
Bruce protocol
Naughton protocol
Weber protocol
ACIP(asymptomatic cardiac ischemia pilot)
Modified ACIP
The Bruce protocol
• 1949 by Robert A. Bruce,
considered the “father of
exercise physiology”.
• Published as a standardized
protocol in 1963.
• gold-standard for detection
of myocardial ischemia when
risk stratification is
necessary.
BRUCE Protocol
Stage
Time (min)
M/hr
Slope
1
0
1.7
10%
2
3
2.5
12%
3
6
3.4
14%
4
9
4.2
16%
5
12
5.0
18%
6
15
5.5
20%
PROTOCOL
USES
COMMENTS
BRUCE
Normally used
large↑Vo2 bet
stages\running≥st 3
NAUGHTON&WEBER
Limited ex tolerance-CCF 1-2 min stages\1 MET
increment
ACIP
Established CAD
MOD-ACIP
Short elderly individuals
2 min stages\> linear ↑
in HR & Vo2
Peak Vo2 is the same regardless of the protocol used
diff – rate at which it is achieved
Procedure
• Standard 12 lead ECG- leads
• Torso ECG + BP
– Supine and Sitting / standing
• HR ,BP ,ECG
– Before,after,stage
– Onset of ischemic response
– Each min recovery(5-10 mints)
Procedure- Lead systems
• Mason-Liker modification-extremity
electrodes moved to torso 2 ↓ motion
artifacts
– RAD
– ↑inf lead voltage
– Loss of inf lead q
– New Q in AVL
Contraindications to Exercise Testing
Absolute
• A/c MI (< 2 d)
• High-risk unstable angina
• Uncontrolled cardiac arrhythmias causing
symptoms or hemo compromise
• Symptomatic severe AS
• Uncontrolled symptomatic CCF
• Acute pulmonary embolus or pulmonary
infarction
• A/c myocarditis or pericarditis
• A/c Ao dissection
Contraindications to Exercise Testing
Relative
• LMCA stenosis
•
•
•
•
•
•
Mod- stenotic VHD
Electrolyte abnormalities
Sev HTN
Tachyarrhythmias or bradyarrhythmias
HOCM and other outflow tract obstructions
Mental or physical impairment leading to
inability to exercise adequately
• High-degree AV block
SAFETY & RISKS
In nonselected pat pop-mortality- .01%
-morbidity-.05%
In k/c CAD- 1 C.arrest/59000 person hours
-AMI in 1.4 / 10000 tests
Arrythmias-AF-Mc-9/10,000 tests
-VT-6/10,000 tests
-VF- .6/10,000 tests
Deaths& MI estimated occur in 1 of 25000 tests
Bayes' theorem
A theory of probability
The post test probability is proportional to
the pretest probability
To diagnose, test sensitivity ,specificity&
prevalence in the population being tested
req
• Sensitivity- a person with the disease having a
positive test.
• Specificity-person without the disease having
a negative test.
• Prevalence- % in the population having
disease.
Pretest Probability
• Based on the pat's h/o ( age, gender, chest pain ),
phy ex and initial testing, and the clinician's
experience.
• Typical or definite angina →pretest probability
high - test result does not dramatically change the
probability.
• Diag power maximal when the pretest probability
is intermediate-30-70%
Classification of chest pain
• Typical angina
1.
Substernal chest discomfort with characterstic quality and
duration
2.
Provoked by exertion or emotional stress
3.
Relieved by rest or NTG
• Atypical angina
Meets 2 of the above characteristics
• Noncardiac chest pain
Meets one or none of the typical characteristics
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%
INTERMEDIATE CATEGORY
AGE GROUP
30-39 YEARS
GENDER & SYMPTOMS
M& F + TYPICAL ANGINA
M + ATYPICAL/ PROBABLE ANGINA
40-49 YEARS
F + TYPICAL ANGINA
M + ATYPICAL/ NON ANGINAL CP
50-59 YEARS
F+ TYPICAL ANGINA
M&F + ATYPICAL NAGINA
M+ NON ACP
60-69 YEARS
M& F+ ATYPICAL/PROB ANGINA
M&F + NACP
E T TO DIAGNOSE OBSTRUCTIVE CAD
Class I
• Adult (including RBBB or <1 mm of resting
ST↓) with intermed pretest probability of
CAD
Class IIa
• Patients with vasospastic angina.
E T TO DIAGNOSE OBSTRUCTIVE CAD
Class IIb
1. Patients - high pretest probability of CAD
2. Patients - low pretest probability of CAD
3. Patients with <1 mm of baseline ST ↓and on digoxin.
4. Patients with LVH and <1 mm baseline ST ↓.
Class III
1. Patients with the following baseline ECG
abnormalities:
• Pre-excitation syndrome
• Electronically paced ventricular rhythm
• >1 mm of resting ST depression
• Complete LBBB
EST
SENSITIVITY
OVERALL
68%
SPECIFICITY
77%
SVD(LAD>RAD>LCX)
25-71%
MULTIVESSEL DIS
81%
66%
LMCA/3-VD
86%
53%
Exercise Testing in Asymptomatic Persons
Without Known CAD
Class I
• None.
Class IIa
• Evaluation of asymP DM pts - plan to start vigorous exercise ( C)
Class IIb
• 1. Eval of pts with multiple risk factors - guide to risk-reduction therapy.
• 2. Eval of asymptomatic men > 45 yrs and women >55 yrs:
Plan to start vigorous exercise
Involved in occupations which impact public safety
High risk for CAD(e.g., PVOD and CRF)
Class III
• Routine screening of asymptomatic
RISK ASSESS AND PROG
IN PAT WITH SYMP OR A
PRIOR HISTORY OF CAD
Class I
1. Initial evalu with susp/known CAD +/- RBBB or <1
mm of resting ST Depression
2.Susp/ known CAD, previously evaluated-+ signi
change in clinical status nw
3. Low-risk UA pts >8 to 12 hrs & free of active
ischemia/CCF
4. Intermed-risk UApts > 2 to 3 days & no active
ischemia/ CCF
Class IIa
Intermed-risk UA pts – initial markers (N),rpt ECG –
no signi change, and markers >6-12 hrs (N) & no
other evidence of ischemia during observation.
AFTER MYOCARDIAL INFARCTION
Class I
• 1. Before discharge (submaximal --4 to 6 days).
• 2. Early after discharge (symptom limited --14 to 21
days).
• 3. Late after discharge if the early exercise test was
submaximal (symptom limited --3 to 6 weeks).
Class IIa
• After discharge as part of cardiac rehabilitation in
patients who have undergone coronary
revascularization.
AFTER MYOCARDIAL INFARCTION
Class IIb
1. Patients with the following ECG abnormalities:
• • Complete LBBB
• • Pre-excit synd
• • LVH
• • Dig therapy
• • >1 mm of resting ST-segment dep
• • paced ventricular rhythm
2. Periodic monitoring in patients who continue to participate in exercise
training or cardiac rehabilitation.
Class III
1. Severe comorbidity likely to limit life expectancy and/or candidacy for
revascularization.
2. any time to eval pts with AMI with uncompensated CCF, arrhythmia, or
noncardiac exercise limiting conditions.
3. Before discharge to evaluate pts who have already been selected for, or
have undergone, cardiac cath.
Submaximal protocols
• predetermined end point, often a peak HR
120 bpm, or 70% predicted max HR or peak
MET – 5
Symptom-limited tests
• to continue till signs or sympt needing
termination (i.e., angina, fatigue, ≥ 2 mm of
ST↓,v. arrhy, or ≥10-mm Hg drop in SBP from
the resting blood pressure)
• The incidence of fatal cardiac events(inclu
fatal MI & cardiac rupture)-- 0.03%
• Nonfatal MI and successfully resuscitated
cardiac arrest -- 0.09%
• Complex arrhythmias, including VT --1.4%.
• Symptom-limited protocols have an event rate
that is 1.9 times that of submaximal tests
High risk predischarge
Present
Absent
Cardiac cath
strategy 2
symp lim EST(14-21d)
strategy3
sub max (4-7d)
Symp lim EST(14-21 days)
Markedly ab
mildly ab
Card cath
Ex imaging
Reversible ischemia
negative
no rev ischemia
Med Rx
Sub max (4-7 days)
Markedly ab
mildly ab
negative
Ex imaging
Rev ischemia
no rev isch
symp lim ex(3-6wks)
card cath
markedly ab
mildly ab
rev isch
negative
no rev isch
Med Rx
E S T Before and After Revascularization
Class I
• 1. Demo of ischemia before revascularization.
• 2. Eval rec symps suggesting ischemia aft revascularization.
Class IIa
• Aft discharge for activity counseling and/or exercise training as part of
rehabilitation in pts aft revascularization.
Class IIb
• 1. Detection of restenosis in selected, high-risk asymptomatic pts < first
12 months aft PCI.
• 2. Periodic monitoring of selected, high-risk asymptomatic ps for
restenosis, graft occlusion, incomplete coronary revascularization, or
disease progression.
Class III
• 1. Localization of ischemia for determining the site of intervention.
• 2. Routine, periodic monitoring of asymptomatic pts after PCI or CABG
without specific indications.
Investigation of Heart Rhythm Disorders
Class I
• 1. Identification of appropriate settings in pts
with rate-adaptive pacemakers.
• 2. Evaluation of cong CHB in pts considering
↑activity/competitive sports. (C)
Class IIa
• 1. Evaluating known or suspected exerciseinduced arrhythmias.
• 2. Evaluation of medical, surgical, or ablative
therapy in exercise-induced arrhythmias
Investigation of Heart Rhythm Disorders
Class IIb
• 1. Isolated VPC in middle-aged pts without
other evidence of CAD.
• 2. Prolonged 1˚AV block or type I-2˚AV block ,
LBBB, RBBB, or VPC in young pts considering
competitive sports. (C)
Class III
• Routine investigation of isolated VPC in
young pts.
IN VALVULAR HEART DISEASE
• Class1-
c/c AR-Fun capacity & symp resp in
pats with equivocal sympt
• Class 2A
c/c AR- FN capacity- athletic activity
prog in c/c AR before AVR
Stress Testing
Modality
Exercise test
Nuclear
Imaging
Stress
Echo
Sensitivity
Specificity
68%
77%
87-92%
80-85%
80-85%
88-95%
EST RESPONSES & INTERPRETATIONS
Normal Response to Stress Testing
•
Heart rate increases
•
Blood pressure increases
•
Cardiac output increases
•
Total peripheral resistance decreases
•
Dysrhythmias – isolated unifocal PVC’s and
PAC’s (suppressed at increased heart rate)
•
Oxygen consumption increases
Abnormal Response
to Stress Testing
•
Heart rate fails to rise above 120 or unable to
attain THR of 85% of max
•
SBP shows a drop
•
Physically unable to complete test
•
Marked hypertension, >260/115
•
Chest Pain and/or unusual shortness of breath
•
Normal Response of ECG
to Stress Testing
ECG Changes
–
–
–
–
–
–
–
–
QRS complex ↓ in size
PR,QRS,QT shorten
J point ↓, resulting in up sloping of ST segment
ST segment returns to baseline by 80
milliseconds
PR segment may down slope(Inf leads– baseline
PQ junction)
R amplitude may decr at rates > 130
P ampl ↑
T wave decreases
The Electrocardiographic Response
The Exercise ECG
1 = Iso-electric
2 = J point
3 = J + 80 msec
• ST 60 -- HR > 130/min
• ST 80 -- HR ≤ 130/min
Criteria for Reading ST-Segment Changes on
the Exercise ECG
ST DEPRESSION:
• Measurements made on 3 consecutive ECG complexes
• ST level is meas rel to the P-Q junction
• When J-point is dep rel to P-Q junction at baseline:
– Net diff from the rest J junction - amount of deviation
• When the J-point is ↑ rel to P-Q junction at baseline and
becomes ↓ isoel with exercise:
– Mag of ST dep - P-Q junction and not the resting J point
Abnormal and Borderline ST-Segment Depression
• ABNORMAL:
– 1.0 mm or > horizontal or downsloping ST dep at
80 msec after J point on 3 consecutive ECG complexes
• BORDERLINE:
– 0.5 to 1.0 mm horizontal or downsloping ST dep at
80 msec after J point on 3 consecutive ECG complexes
– 1.5 mm or > upsloping ST dep at 80 msec after J
point on 3 consecutive ECG complexes
ECG changes during stress test
Normal
Rapid Upsloping
Minor ST
Depression
Slow Upsloping
Horizontal
Downsloping
Elevation (non Q
lead)
Elevation (Q wave
lead)
ECG Patterns Indicative of Myocardial Ischaemia
ECG Patterns Not Indicative of Myocardial Ischaemia
• 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.
• 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.
• “slow upsloping” ST segment
at peak exercise indicates an
ischemic pattern in patients
with a high coronary disease
prevalence pretest.
•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.
• abnormal at 9:30 minutes
ES test and resolves in the
immediate recovery phase.
•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.
ST Elevation
Abnormal response
– J ↑ ≥0.10mV(1 mm)
– ST 60 ≥0.10mV(1 mm)
– Three consecutive beats
Q wave lead (Past MI)
• Severe RWMA, ↓EF, ↓Prognosis
Non Q wave lead (Past MI)
• Severe ischemic response
• Localise the culprit
Non Q wave lead (No past MI)-1%
• Transmural reversible myocardial ischemia-vasospasm, ↑coronary narrowing
---
•ST segment elevation 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
•pattern is usually associated with a fullthickness, reversible myocardial perfusion
defect in the corresponding left
ventricular myocardial segments and
high-grade intraluminal narrowing at
coronary angiography
• coronary vasospasm produces this
result in the absence of significant
intraluminal atherosclerotic narrowing
Confounders of EST Interpretation
• Digoxin
– abnormal ST-segment response to exercise.
– occurs in 25% to 40%
– directly related to age.
• LVH
– ↓ specificity of EST, sensitivity unaffected.
– still the first test
– Ab test- ref to add tests
• Resting ST ↓
– Resting ST-segment ↓ -even otherwise adverse
• LBBB
– Ex-induced ST ↓ -no asso with ischemia
– no level of ST-seg dep - diag
• RBBB
– do not ↓ sensitivity, specificity, or predictive value
• β- # THERAPY
– routine- unnecessary- to stop beta-blockers-† symp
– in patients taking -↓ diag & prog value - inadequate HRR
ERS and resting ST↑
• Return to the PQ Jn –nl
• ST↓ meas from PQ jn
• Not from the elevated J point before ex.
Duke Treadmill Score
Treadmill Score =
Ex.tme (min)
-5х (ST-seg dev in mm)- 4х ex.angina index
(0-no angina, 1 angina, 2 if angina stops test)
High Risk= -11, mortality - >5% annually
Low Risk= +5, mortality - 0.5% annually
DUKE TM SCORE
• Independent prog information
• =y good in males & females
• Not as effective in age≥ 75 yrs
ACC/AHA Guidelines:
high-risk test result- mortality ≥ 4%/yr→ for
cardiac cath
Intermediate-risk result -mortality 2- 3%/yr→
additional testing- cardiac cath, exercise
imaging study
Pseudo normalization pattern of T
• No prior MI
Nondiagnostic finding
• Prior MI
Sugg Reversible myocardial ischemia
Needs - rev myo perfusion defect
R Wave amplitude
LVH Voltage criteria
• ST seg – less reliable to ∆ CAD even in the
absence of LV strain pattern
Loss of R wave (MI)
• ↓Sensitivity of ST response in that lead
U inversion
Occ in precordial leads at HR<120
• Relatively insensitive but
• Relatively specific 4 CAD
ST/HR SLOPE MAESUREMENTS
• HR adj of ST seg dep-↑ sensitivity
• ST/HR slope of 2.4 mV/beats/min-abnormal
• >6mV/beats/min -3 vessel disease
• CORNELL protocol-gradual inc in HR
• ST seg/HR index-av change of ST dep with HR
through out the course of ex test
• > 1.6 -abnormal
Abnormal BP Response
• Failure to ↑SBP >120 mmHg
• Sustained ↓(15 secs) >10mmHg
• ↓SBP below resting BP during progressive exe
• Inadequate ↑ of CO
• Hypo episode 3- 9% of symp pats
 Extensive CAD & perfusion defects
 LMCA/ 3 VD
Exercise Capacity
VO2 max = (mph x 26.8) x (0.1 + [% grade X 1.8] + 3.5
2
Stage 1 =
5 METS
Stage 2 = 6 - 8 METS
Stage 3 = 8 -10 METS
1-MET ↑in exercise capacity, the survival improved by
12 %
N Engl J Med 2002
Heart rate response
Chronotropic incompetence-adv prog
• Inability to attain THR OR
• Ab HRR (<80%)
{%HR Reserve=(HRpeak-HRrest)/(220-age- HRrest)}
Chronotropic index
• ANS dysfunction,SN dysfuntion, drugs,
myocardial ischemia
• ↑long term mortality-< 80%CI (not on β
blockers)
Heart Rate Recovery
-Rapid reactivation of vagal tone - ↓
in heart rate post ex- nl
-Slow decceleration post ex
-↓ vagal tone
HRR=HR (peak)-HR (1 min later)
TMT (upright)
< 12 bpm
TMT (supine)
< 18 bpm
upright value <22 bpm at 2 minutes is abnormal
Prognostic power independent of other factors
HRR Predicts Outcome in CAD
Exercise induced Chest discomfort
• Usually after ischemic ST changes
• +/-↑DBP
• chest discomfort –only sgn of CAD
• In CSA, CP less freq than ST↓
Angina with no ST ↓- MPI to assess ischemic
severity.
(+) Stress Test with angina →
5%/yr.( mortality)
(+) Stress Test, no angina →
2.5%/yr.
Adverse prognosis & multivessel CAD
• Symptom limiting exercise < 5METs
• Abnormal BP response
• ST↓ ≥2mm or downsloping ST↓→
<5METs, ≥5 leads, persisting ≥5 mins into recovery
• ST↑( except aVR)
• Angina at low exercise work loads
• Reproducible sustained/symptomatic VT
Indications for Terminating Exercise Testing
Absolute indications
• ↓ SBP >10 mm Hg fm baseline +other evidence of
•
•
•
•
•
•
•
ischemia
Mod - severe angina
↑ CNS sympts (ataxia, dizziness, or near-syncope)
Signs of poor perfusion (cyanosis or pallor)
Technical diff in monitoring ECG or systolic BP
Subject’s desire to stop
Sustained VT
ST ↑ (≥1.0 mm) in leads without Q-waves (other
than V1 or aVR)
Relative indications
• ↓ in S BP (≥10 mm Hg) in the absence of other
evidence of ischemia
• ST or QRS changes - excessive ST↓ (>2 mm of
horizontal or downsloping ST↓ ) or marked axis shift
• Arrhythmias other than sustained VT, including
multifocal PVCs, triplets of PVCs, SVT, heart block, or
bradyarrhythmias
• Fatigue, shortness of breath, wheezing, leg cramps,
or claudication
• Devp of BBB or IVCD that cannot be distinguished
from VT
• Increasing chest pain
• Hypertensive response(250/115 mm hg)
Sub maximal ex test
• Signs & sympt of ischemia
• Att of a work load of 6 METS
• 85% of APMHR
• HR of 110 beats / min –on β blockers
• BORG score 17
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