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.