Procedure: Exercise ECG

Guidance for medical examiners when assessing a patient for either a general topic or condition - Exercise ECG.

Indication

• Positive Coronary Risk Index (Coronary Risk Index is >14)
• Clinical indication or known disease association
• Risk-stratification post intervention

Procedural requirements

• Bruce protocol with a 12-lead ECG, with monitoring for at least 6 minutes and up to 15 minutes after cessation of exercise
• Applicant to reach at least 100% of predicted heart rate and at least nine minutes on the Bruce protocol or equivalent on the bicycle ergometer (maximum predicted heart rate = 220 beats per minute minus applicant's age in years for men, 200 beats per minute minus applicant's age in years for women)
• Treadmill exercise is preferred but bicycle exercise is acceptable if the applicant is unable to perform on the treadmill
• Applicant should have been continuously in the time zone where testing is performed for at least 72 hours prior to the test
• Applicants should normally cease taking any beta-blocker 48 hours prior to the stress test, unless the medication is used to treat known ischaemic heart disease or a significant arrhythmia. When a beta-blocker is not so ceased prior to stress testing an applicant, an explanation of the reason is required from the treating or investigating cardiologist who supervises the stress test
• All reports of stress tests should include the following details:
  • exercise protocol used
  • exercise capacity in terms of
    • protocol level
    • duration of exercise (with comment if less than nine minutes)
    • workload achieved – metabolic equivalent (METS)
  • baseline and maximum heart rate achieved level of perceived exhaustion of the applicant
  • any symptoms experienced by the applicant
  • reason for termination of the test
  • heart rate response and any arrhythmia during recovery.

Exercise echocardiogram or myocardial perfusion scan

• An exercise echocardiogram provides additional information over a stress ECG test, so may be considered by applicants as a primary screening test (dependent on local availability and cost)
• The procedural requirements above also apply to exercise echocardiogram and myocardial perfusion scan
• Applicants with positive or equivocal stress ECG results will be required to undertake an exercise echocardiogram or myocardial perfusion scan to exclude reversible myocardial ischaemia

Interpretation

• A positive stress electrocardiogram is defined by 1.0 mm or more of horizontal or down-sloping ST segment depression at 0.08 sec after the J point
• A positive stress ECG is of adequate diagnostic validity if recorded when an applicant's exercise capacity, heart rate and blood pressure responses reach at least 85% of predicted for age, sex, height and weight, and where the ST segment shift is consistent with ischaemia
• A rise of more than 20 mm in systolic blood pressure response is expected. If the applicant returns a positive stress ECG with ST changes before reaching 100% of designated criteria, it is a matter of even greater aeromedical concern

Further actions

• All stress tests must be interpreted by a cardiologist
• Unrestricted certification is not possible unless, in addition to any other requirements, a negative functional test (i.e. exercise echocardiogram or myocardial perfusion scan) has been received
• Coronary angiography does not provide adequate risk stratification. Aviation regulators tend to favour functional test results from stress ECG, exercise echocardiogram or myocardial perfusion scan on the basis of better prognostic information and risk stratification over anatomical tests such as coronary angiography
• As per guidelines published by the Royal Australian College of General Practitioners, Coronary Computer Tomography Angiography (CCTA) and Computer Tomography (CT) Calcium Scoring are not appropriate as screening tools for coronary artery disease. However, if a test has been conducted, please forward the report to CASA to aid with risk assessment

Pilot information

• Exercise electrocardiograms are a screening test for the presence of Ischaemic Heart Disease (IHD) but do not provide conclusive evidence of the presence of IHD. Applicants need not refrain from exercising privileges simply because they are required to undertake a stress test
• However, pilots with a POSITIVE exercise test, as reported by a cardiologist, must ground themselves until cleared by CASA to resume exercising the privileges of their medical certificate

References

• ABC of clinical electrocardiography - BMJ 2002 May 4; 324(7345): 1084-1087