Exercise Stress Test Interpretation with Resting ST Changes

Introduction to Resting ST Changes

Baseline ST-segment abnormalities (≥1 mm ST depression at rest) interfere with the accurate interpretation of exercise-induced ST changes, which are the primary marker used to detect myocardial ischemia during standard exercise ECG testing, according to the American Heart Association 1, 2, 3
The sensitivity of exercise ECG for detecting obstructive coronary artery disease drops significantly when resting ECG abnormalities are present, as the test relies on comparing exercise-induced ST changes to a normal baseline, as stated by the American College of Cardiology 1, 3

Stress imaging modalities provide greater diagnostic accuracy than exercise ECG alone and are specifically indicated when baseline ECG abnormalities limit accurate interpretation, as recommended by the American Heart Association 1, 2
Exercise echocardiography has sensitivity ranging from 71-97% and specificity from 64-100% for detecting coronary artery disease in women, substantially better than standard exercise ECG in patients with resting abnormalities, according to the American Society of Echocardiography 2, 3, 5
Nuclear perfusion imaging (using technetium-99m sestamibi or similar agents) provides direct visualization of myocardial blood flow and can identify ischemia even when ECG interpretation is compromised, as stated by the American College of Cardiology 2, 3

For preoperative risk stratification in a patient with resting ECG abnormalities, stress testing with imaging is recommended, as stated by the American College of Cardiology 6, 3
If the patient can exercise adequately, exercise stress echocardiography or exercise nuclear imaging is preferred over pharmacological stress testing, according to the American Heart Association 1, 2, 5
If physical limitations prevent adequate exercise, pharmacological stress imaging with dobutamine, adenosine, or dipyridamole should be used, as recommended by the American College of Cardiology 1, 2, 5

A "normal" exercise ECG in the presence of resting ST changes does NOT rule out significant coronary artery disease or coronary microvascular dysfunction, as stated by the American Heart Association 1
The false reassurance from an uninterpretable "negative" test could delay appropriate diagnosis and treatment, making repeat testing with imaging essential before proceeding with surgery, according to the American College of Cardiology 1, 2, 3