High-frequency QRS electrocardiogram analysis during exercise stress testing for detecting ischemia.
Jonathan A Lipton1, Stafford G Warren, Mike Broce
1Erasmus Medical Center, Rotterdam, The Netherlands. jonathanlipton@gmail.com
International Journal of Cardiology
|April 28, 2007
Summary
High-frequency QRS analysis (HFQRS) shows increased relative changes in ischemic patients during exercise stress tests. This RCQ index may enhance the diagnosis of myocardial ischemia.
Area of Science:
- Cardiology
- Medical Diagnostics
- Biomedical Engineering
Background:
- Electrocardiogram (ECG) stress testing is a standard, cost-effective method for detecting myocardial ischemia.
- High-frequency QRS (HFQRS) analysis offers potential to improve the accuracy of ECG stress testing.
Purpose of the Study:
- To compare HFQRS during exercise in patients with and without myocardial ischemia.
- To evaluate the utility of the relative change in HFQRS (RCQ) index for diagnosing ischemia.
Main Methods:
- Recorded high-resolution ECGs from 139 patients undergoing nuclear stress testing.
- Calculated the RCQ index by averaging the two leads with the greatest relative change in HFQRS.
- Compared RCQ index values between ischemic and non-ischemic patient groups.
Main Results:
- The RCQ index was significantly greater in patients with ischemia (45%) compared to non-ischemic patients (34%; P=0.0069).
- Ischemic patients exhibited a higher incidence of prior myocardial infarction and coronary intervention.
- Non-ischemic patients had a higher body mass index.
Conclusions:
- The maximum decrease in HFQRS, quantified by the RCQ index, is greater in patients with myocardial ischemia.
- The RCQ index shows promise for improving the diagnostic accuracy of exercise stress testing for ischemia.
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