Author + information
- Received October 7, 1994
- Revision received January 26, 1995
- Accepted February 2, 1995
- Published online June 1, 1995.
- Peter M. Okin, MD, FACC* and
- Paul Kligfield, MD,FACC
- ↵*Address for correspondence:Dr. Peter M. Okin, The New York Hospital-Cornell Medical Center, 525 Fast 68th Street, New York, New York 10021.
Analysis of the rate-related change in exercise-induced ST segment depression using the exercise ST segment/heart rate slope and ST segment/heart rate index can improve the accuracy of the exercise electrocardiogram (ECG) for the identification of patients with coronary artery disease, recognition of patients with anatomically or functionally severe coronary obstruction and detection of patients at increased risk for future coronary events. These methods provide a more physiologic approach to analysis of the ST segment response to exercise by adjusting the apparent severity of ischemia for the corresponding increase in myocardial oxygen demand, which in turn can be linearly related to increasing heart rate. Solid-angle theory provides a model for the linear relation of ST segment depression to heart rate during exercise and a framework for understanding the relation of the ST segment/heart rate slope to the presence and extent of coronary artery disease. False positive and false negative test results of the heart rate-adjusted methods are well known in selected populations and require further clarification. Application of these methods is also highly dependent on the type of exercise protocol, number of ECG leads examined, timing of ST segment measurement relative to the J point and accuracy and precision of ST segment measurement. These methodologic details have been an important limitation to test application when traditional protocols and measurement procedures are required. When applied with attention to required details, the heart rate-adjusted methods can improve the usefulness of the exercise ECG in a range of clinically relevant populations.
This study was supported by grants from the Elizabeth and Robert Rosenan Charitable Foundation and the David and Hope G. Solinger Foundation, Inc., New York, New York.
- Received October 7, 1994.
- Revision received January 26, 1995.
- Accepted February 2, 1995.
- American College of Cardiology