Exercise Stress Test

1. See Also
   1. Stress Imaging
   2. Pharmacologic Stress Test
2. Efficacy: False positive rate
   1. Women: 17%
   2. Men: 11%
3. Preparation
   1. Hold all Beta Blockers 24 hours before test
   2. Hold nitrates (Nitroglycerin) on day of the test
4. Indications: Asymptomatic subjects
   1. No absolute indications
   2. 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
      5. Patient with Diabetes Mellitus
         1. Age over 35 years or
         2. Type 2 diabetes >10 years
         3. Type 1 diabetes >15 years
         4. Secondary complications (Neuropathy, retinopathy)
      6. Patient with Cardiac Risks and age >45 years old
         1. Cardiac Risk Factors: 2 or more risk factors
         2. Sedentary patient planning new Exercise program
5. Indications: Symptomatic subjects
   1. Definite indications
      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
         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 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
6. Contraindications
   1. Aortic Dissection
   2. Critical Aortic Stenosis
   3. Critical Left Ventricular outflow-tract obstruction
      1. Idiopathic Hypertrophic Subaortic Stenosis (IHSS)
   4. Inability to Exercise to adequate level of exertion
      1. Unable to perform 5 minutes on Bruce Protocol
   5. Uninterpretable Electrocardiogram
      1. Left Bundle Branch Block (Adenosine Nuclear 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
   6. Recent or active cerebral ischemia
   7. Severe uncontrolled Hypertension
   8. Uncompensated Congestive Heart Failure
   9. Unstable Angina
   10. Digoxin Use (Class IIB Recommendation)
   11. Cardiac revascularization within last 5 years
7. 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
8. 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
9. Interpretation: Prognostic Duke Treadmill Score
   1. Background
      1. Score developed for patients with median age 49
      2. Alternatively, ability to perform 6 mets on Bruce protocol is as predictive as Duke Score
      3. Not predictive in patients over age 75 years
         1. Kwok (2002) J Am Coll Cardiol 39:1475-81
   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: 5 or more
         1. Four-year survival 98-99%
      2. Intermediate Risk: Between -10 and +5
      3. High death risk: Below -10
         1. Four-year survival 71-79%
10. References
    1. Lee (2001) N Engl J Med 344:1840-5