Exercise Stress Test with Resting ST Changes: Interpretation and Next Steps
What This Means
The statement indicates that while your stress test showed no evidence of ischemia, the presence of baseline ST-segment abnormalities on your resting ECG significantly reduces the test's ability to accurately detect coronary artery disease, making the "negative" result unreliable. 1
Why Resting ST Changes Are Problematic
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 1
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 1
Other conditions that similarly limit interpretation include left bundle branch block, paced rhythm, Wolff-Parkinson-White syndrome, left ventricular hypertrophy with strain, or digitalis therapy 1, 2
Recommended Next Step: Stress Imaging
You should undergo stress testing with an imaging modality (stress echocardiography or nuclear myocardial perfusion imaging) rather than relying on the exercise ECG alone. 1
Why Imaging Is Superior in Your Case
Stress imaging modalities provide greater diagnostic accuracy than exercise ECG alone and are specifically indicated when baseline ECG abnormalities limit accurate interpretation 1
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 1
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 1
Imaging provides additional critical information including the location and extent of ischemic myocardium, left ventricular function, and territory at risk—information not available from ECG alone 1
Clinical Context for Preoperative Assessment
For preoperative risk stratification in a 45-year-old woman, stress testing with imaging is recommended when the resting ECG has baseline abnormalities that limit interpretation 1
If you can exercise adequately, exercise stress echocardiography or exercise nuclear imaging is preferred over pharmacological stress testing 1
If physical limitations prevent adequate exercise (inability to achieve 4-5 METs or 85% maximum predicted heart rate), pharmacological stress imaging with dobutamine, adenosine, or dipyridamole should be used 1
Important Caveats
A "normal" exercise ECG in the presence of resting ST changes does NOT rule out significant coronary artery disease or coronary microvascular dysfunction 1, 3, 4
Recent evidence shows that ST-segment changes during exercise can reflect coronary microvascular dysfunction even without obstructive coronary disease, particularly in women with angina and nonobstructive coronary arteries 3
The false reassurance from an uninterpretable "negative" test could delay appropriate diagnosis and treatment, making repeat testing with imaging essential before proceeding with surgery 1
Specific Recommendation for Your Surgeon
Request either exercise stress echocardiography or exercise nuclear perfusion imaging for accurate preoperative cardiac risk assessment, as your resting ECG abnormalities make the standard exercise ECG test inadequate for ruling out myocardial ischemia. 1