Exercise Stress Test

Aka: Exercise Stress Test, Exercise Electrocardiography, Duke Treadmill Score, Exercise Treadmill Test

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II. Efficacy: False Positive Rate

  1. Women: 17%
  2. Men: 11%

III. Preparation

  1. Hold all Beta Blockers 24 hours before test
  2. Hold nitrates (Nitroglycerin) on day of the test

IV. Technique

  1. Typically performed on treadmill (but may be performed on Exercise bike)

V. Precations

  1. Exercise Stress Testing is best at excluding coronary disease rather than confirming coronary disease
  2. Avoid stress testing asymptomatic patients (without revascularization history)
    1. Even those with Cardiac Risk Factors do not have fewer coronary events (fatal or non-fatal)
    2. Young (2009) JAMA 301(15): 1547-55 [PubMed]
  3. Stress tests in asymptomatic patients has risks
    1. False Positives and unnecessary invasive testing (e.g. angiography)
    2. Sudden Cardiac Death or hospitalization (NNH: 10000)

VI. Indications: Asymptomatic subjects

  1. Preoperative evaluation
    1. Unable to perform 4 METS of Exercise OR
    2. Cardiac symptoms on exertion OR
    3. Planned vascular surgery, or liver or Kidney Transplant
  2. Pre-Vigorous Exercise Program (>6 METS) evaluation in deconditioned patients with Cardiac Risk Factors
    1. Diabetes Mellitus OR
    2. Men over age 45 years old (women over age 55 years old) OR
    3. Two or more Cardiac Risk Factors
  3. Asymptomatic patietns with history of revascularization
    1. Percutaneous coronary interventing (stenting) >2 years prior
    2. Coronary Artery Bypass Graft (CABG) >5 years prior
  4. Other possible indications
    1. Special occupation
      1. Pilot
      2. Police officer
      3. Bus driver
    2. Valvular heart disease: Aortic Regurgitation
    3. Cardiac rhythm disorders
      1. Rate-adaptive Pacemaker assessment
      2. Sports Physical for congenital complete Heart Block
      3. Exercise-induced rhythm disturbance evaluation
    4. Pre-Hypertension Evaluation: Diagnostic criteria
      1. Peak systolic Blood Pressure >214 or
      2. High systolic Blood Pressure >3 minutes in recovery
      3. High diastolic pressure >3 minutes in recovery

VII. Indications: Symptomatic subjects

  1. First-line study to assess CAD risk where intermediate risk
    1. See contraindications below
    2. See Angina Diagnosis to determine those with intermediate risk
    3. Requires normal baseline EKG (otherwise requires Stress Imaging)
    4. No prior revascularization procedures such as PTCA, CABG (requires Stress Imaging)
    5. Ability to Exercise at least 5 METS (requires Pharmacologic Stress Testing)
    6. No Diabetes Mellitus (requires Stress Imaging)
  2. Acute Coronary Syndrome Assessment (Low Risk Chest Pain evaluation)
    1. Must have <1 mm resting ST depression
    2. Significant change in clinical status
    3. Atypical symptoms in men or menopausal women
    4. Unstable Angina without active Angina or Congestive Heart Failure
      1. See Acute Coronary Syndrome for risk levels
      2. Low Risk Chest Pain patient after 8-12 hours observation
      3. Intermediate risk and following criteria met
        1. Normal Cardiac Markers at 0 and 6 hours and
        2. No change in serial electorcardiograms and
        3. No evidence of active ischemia
  3. Assess patient with Exercise-induced Dysrhythmia
    1. Also see asymptomatic patients above
  4. Known Coronary Artery Disease
    1. Precaution
      1. Do not stress test if recent revascularization procedure
      2. Stress testing is not recommended unless change in function or acute event
      3. In addition, Stress Imaging is preferred if known Coronary Artery Disease
    2. Post-Myocardial Infarction to assess prognosis
      1. Submaximal stress test
        1. Pre-discharge: 4-6 days post-MI or
        2. Post-discharge: 14-21 days post-MI
      2. Symptom-limited stress test at 3-6 weeks post-MI

VIII. Contraindications

  1. Myocardial Infarction in prior 2 days
  2. Active Endocarditis
  3. Acute Aortic Dissection
  4. Critical Aortic Stenosis (symptomatic)
  5. Acute Myocarditis
  6. Acute Pericarditis
  7. Critical Left Ventricular outflow-tract obstruction
    1. Idiopathic Hypertrophic Subaortic Stenosis (IHSS)
  8. Inability to Exercise to adequate level of exertion
    1. Unable to perform 5 minutes on Bruce Protocol
    2. Consider pharacological Stress Imaging modalities
  9. Uninterpretable Electrocardiogram (Stress Imaging instead)
    1. Left Bundle Branch Block (Adenosine Nuclear scan needed)
    2. Electronically paced rhythm (Pacemaker)
    3. WPW Syndrome
    4. Abnormal ST Segments (>1 mm ST abnormality)
      1. Includes Digoxin
      2. Includes Left Ventricular Hypertrophy
  10. Recent or active cerebral ischemia (TIA or CVA)
  11. Severe, Uncontrolled Hypertension (SBP >200 mmHg or DBP >110 mmHg)
  12. Uncompensated Congestive Heart Failure
  13. Unstable Angina
  14. Digoxin Use (Class IIB Recommendation)
    1. Digoxing is associated with high stress test False Positive Rate (use Stress Imaging instead)
  15. Cardiac revascularization within last 5 years

IX. Protocol: Prematurely stopping the test

  1. Absolute indications to stop the test
    1. CNS symptoms (e.g. Ataxia, Dizziness, Near Syncope)
    2. Despite increased workload, systolic Blood Pressure drops >10 mmHg (with symptoms of ischemia)
    3. Moderate to severe Angina
    4. Poor perfusion signs (Cyanosis, pallor)
    5. ST Segment Elevation >1 mm in leads without preexisting Q Waves (outside aVR, aVL, V1)
    6. Significant Arrhythmia (e.g. sustained Ventricular Tachycardia, second or third degree AV Block)
    7. Unable to continue monitoring (e.g. Blood Pressure, ekg)
    8. Patient asks to stop test
  2. Relative indications to stop the test
    1. Other Arrhythmias not listed above (e.g. Supraventricular Tachycardia, Bradyarrhythmias)
    2. Bundle Branch Block not distinguishable from Ventricular Tachycardia
    3. Claudication (or Fatigue or Leg Cramps)
    4. Wheezing or significant Shortness of Breath
    5. Despite increased workload, systolic Blood Pressure drops >10 mmHg (withOUT symptoms of ischemia)
    6. Exaggerated hypertensive response (>250/115 mmHg)
    7. Heart Rate 85% of expected maximum for age
    8. Increasing Chest Pain
    9. ST segment Depression (horizontal or down sloping) >2 mm with suspected ischemia

X. Interpretation: Poor prognostic findings

  1. Low workload
    1. Mets <6.5
    2. Time: < 5-6 minutes on Bruce protocol
  2. Low peak Heart Rate
    1. Pulse < 120 without Beta-Blocker therapy
  3. Systolic Blood Pressure decreased or flat response
    1. Remains under 130 mmHg
  4. ST segment Depression >2mm
  5. ST segment Depression in multiple leads
  6. Prolonged ST depression after Exercise (>6 min)
  7. ST Elevation without abnormal Q Wave
  8. Increase in complex ventricular ectopy
  9. Exercise-induced typical Angina
  10. Frequent ventricular ectopy
    1. Frolkis (2003) N Engl J Med 348:781-90 [PubMed]

XI. Interpretation: Predictors of mortality in women

  1. Decreased peak Exercise capacity
  2. Delayed Heart Rate recovery
  3. ST depression on Exercise was not related to mortality
  4. Mora (2003) JAMA 290:1600-7 [PubMed]

XII. Interpretation: Prognosis based on METS

  1. Ability to perform 6 mets on Bruce protocol is as predictive as Duke Score
  2. Ability to perform >10 METS on Bruce Protocol is associated with a low risk of death
    1. Myers (2002) N Engl J Med 346(11): 793-801 [PubMed]
    2. Fine (2013) Mayo Clin Proc 88(12): 1408-19 [PubMed]

XIII. Interpretation: Prognostic Duke Treadmill Score

  1. Background
    1. Score developed for patients with median age 49
    2. Alternatively, METS performed are predictive of prognosis (see above)
    3. Not predictive in patients over age 75 years
      1. Kwok (2002) J Am Coll Cardiol 39:1475-81 [PubMed]
  2. Calculation
    1. Start with Exercise Time (minutes)
    2. Subtract (5 x ST segment Depression mm)
    3. Subtract (4 x treadmill Angina score)
      1. No Angina: 0
      2. Non-limiting Angina: 1
      3. Limiting Angina: 2
  3. Interpretation
    1. Low death risk: 7 or more
      1. Five-year survival: 93%
    2. Intermediate Risk: Between -10 and +5
    3. High death risk: Below -10
      1. Four-year survival 71-79%
  4. References
    1. Mark (1987) Ann Intern Med 10696): 793-800 [PubMed]

XIV. References

  1. Garner (2017) Am Fam Physician 96(5): 293-9 [PubMed]
  2. Lee (2001) N Engl J Med 344:1840-5 [PubMed]

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