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Exercise Treadmill Testing
Introduction to Treadmill Test
• Indications and Safety • Equipment and Protocols • Exercise End Points • Basics of Interpretation of the Exercise Test
SAFETY
Generally safe, but myocardial infarction and death up to 1 per 2500 test.
should be supervised by physician. ECG, heart rate, and blood pressure to be
monitored carefully and recorded during each stage of exercise and during ST-segment abnormalities and chest pain.
CLASS I INDICATIONS FOR PERFORMING AN EXERCISE TEST
To assist in the diagnosis of CAD in adult patients with an intermediate pretest probability of disease.
To assess functional capacity and to aid in assessing the prognosis of patients with known CAD.
To evaluate the prognosis and functional capacity of patients with CAD soon after an uncomplicated myocardial infarction.
To evaluate patients with symptoms consistent with recurrent, exercise-induced cardiac arrhythmias.
CLASS II INDICATIONS FOR PERFORMING AN EXERCISE TEST
To evaluate asymptomatic men >40 and women >50 who: are involved in special, high risk occupations; plan to start a vigorous exercise program; have multiple cardiac risk factors.
To assist in the diagnosis of CAD in adult patients with a high or low pretest probability of disease.
To evaluate patients with a Class I indication who have baseline electrocardiographic changes.
CLASS III INDICATIONS FOR PERFORMING AN EXERCISE TEST
Routine screening of asymptomatic men or women.
To evaluate men or women with a history of chest discomfort not thought to be of cardiac origin.
To evaluate patients with simple PVCs on a resting ECG with no other evidence of CAD.
To assist in the diagnosis of CAD in patients with evidence of LBBB or WPW on a resting ECG.
CONTRAINDICATIONS FOR ETT
Absolute Acute myocardial infarction (within 2 days) High-risk unstable angin Uncontrolled cardiac arrhythmias Symptomatic severe aortic stenosis Uncontrolled symptomatic heart failure Acute pulmonary embolus or pulmonary
infarction Acute myocarditis or pericarditis Acute aortic dissection
CONTRAINDICATIONS FOR ETT
Relative Left main coronary stenosis Moderate stenotic valvular heart
disease Electrolyte abnormalities Severe arterial hypertension Tachy or Brady arrhythmias HOCM and other outflow
obstructions Mental or physical impairment High-degree atrio-ventricular block
THE TYPES OF EXERCISE MACHINES
Bicycle Ergo meter Treadmill Test
SUPINE STRESS TEST
BRUCE PROTOCOL
Bruce stage Speed and Gradient Minutes METs
Stage 1 1.7 mph + 10% Gradient 3 5
Stage 2 2.4 mph + 12% Gradient 6 7
Stage 3 3.1 mph + 14% Gradient 9 10
Stage 4 3.8 mph + 16% Gradient 12 13
Stage 5 4.6 mph + 18% Gradient 15 17
Stage 6 5.5 mph + 20% Gradient 18 20
LEAD SELECTION FOR ANALYSIS
Lead V5 alone consistently outperforms other leads.
Exercise-induced ST-segment only in inferior leads is not significant for CAD.
Down sloping or horizontal ST-segment is a stronger predictor of CAD but not up sloping ST
THE MEASUREMENTS IN ETT
Electrocardiographic Hemodynamic Symptomatic
Max ST and ST Max ETT Heart Rate Exercise Angina
ST sloping down, up or Max ETT - SBP Exercise limiting Sympt.
No. of leads showing ST change Max ETT Double product Time to onset of angina
ST duration into recovery Exercise hypotension Exercise up to stage IV
ST/HR Index, Time to onset Exercise in METs, minutes
ETT induced ventricular arrhythmia Chronotropic failure
KEY POINTS OF EXERCISE TESTING
Only Manual SBP measurement for safety
Age predicted Heart Rate Targets
The BORG Scale of Perceived Exertion
METs - not ‘Minutes’ have to be used
Use standard ECG analysis + 3 minute recovery
Use scores, Heart rate recovery
ST segment changes alone will not suffice
KEY MET VALUES
o 1 MET = "Basal" = 3.5 ml O2 /Kg/min
o 2 METs = 2 mph on level
o 4 METs = 4 mph on level
o < 5METs = Poor prognosis if < 65 years
o10 METs = Medical Rx as good as CABG
o 13 METs = Excellent prognosis
o 16 METs = Aerobic master athlete
o 20 METs = Super athlete
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 < -1079% 4-year survivalModerate Risk = treadmill score -10 to +495% 4-year survivalLow Risk = treadmill score >+599% 4-year survival
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
WHEN TO TERMINATE ETT ?Absolute indications Drop in SBP of >10 mm Hg from baseline BP with
accompanying evidence of ischemia Moderate to severe angina Increasing nervous system symptoms ataxia,
dizziness Signs of poor perfusion (cyanosis or pallor) Technical difficulties in monitoring ECG or SBP Subject’s desire to stop; Sustained ventricular
tachycardia ST elevation (≥1.0 mm) in leads without diagnostic Q
WHEN TO TERMINATE ETT ?Relative indications Drop in SBP of ≥10 mm Hg BP without ischemia ST or QRS changes - ST depression (>2 mm of
horizontal or down sloping ST-segment ↓) or axis shift
Arrhythmias VT, multifocal PVCs, triplets of PVCs, SVT,
Heart block or brady arrhythmias, BBB or IVCD Fatigue, shortness of breath, wheezing, leg cramps,
IC Increasing chest pain; Hypertensive response >
250/115
RESULTS REPORTING – PAGE 2
1. Exercise CapacityMETS achieved: _______________Minutes exercised: _______________
2. Clinical response to exerciseChest pain during test? ___________Chest pain reason for stopping test? __________Perceived exertion scale (BORG scale reached – 6 to 20):
_________Reason for stopping test:_____________
3. Electrocardiographic response to exerciseST 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:____________________________________________________
4. Hemodynamic response to exerciseSystolic BP response: ______________Diastolic BP response: ______________Maximum heart rate achieved: ________________2 minute heart rate recovery (should be at least 22 bpm by 2
minutes): ______________
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:__________________________________________________________________________________________________________________________________________________________________________________________
RESULTS REPORTING – PAGE 3
Duke Nomogram for 2 mm depression, non-limiting chest
pain at 5 METS.