Author + information
- Received March 4, 1991
- Revision received April 22, 1991
- Accepted May 25, 1991
- Published online November 15, 1991.
- Peter M. Okin, MD, FACC∗,
- Geoffrey Bergman, MD and
- Paul Kligfield, MD, FACC
- ↵∗Address for reprints: Peter M. Okin, MD, The New York Hospital-Cornell Medical Center, 525 East 68th Street, New York, New York 10021.
To assess the effect of heart rate adjustment of the magnitude of the ST integral (ST-HR integral) on exercise test performance, the exercise electrocardiogram (ECG) of 50 clinically normal subjects and 100 patients with known or suspected coronary artery disease was analyzed. At matched specificity of 96% with standard ECG criteria (≥0.1 mV of additional horizontal or downsloping ST segment depression), ar unadjusted ST integral partition of 16 μV-s identified coronary disease in the 100 patients with known or suspected disease with a sensitivity of only 41%, a value significantly lower than the 59% sensitivity of standard ECG criteria (p < 0.01) and the 65% sensitivity of an ST depression partition of 130 μV (p < 0.001).
However, test performance of the ST integral was greatly improved by simple heart rate adjustment: at a matched specificity of 96%, an ST-HR integral partition of 0.154 μV-s/beat per min identified coronary disease in the 100 patients with a sensitivity of 90%, a value significantly greater than the 59% sensitivity of standard criteria and 65% sensitivity of ST depression criteria (each p < 0.001) and similar to the 91% sensitivity of the ST-HR index and 93% sensitivity of the ST-HR slope (each p = NS). Comparison of receiver-operating characteristic curves confirmed the superior overall test performance of the ST-HR integral relative to the ST integral and ST segment depression, and demonstrated improved performance that was comparable with that of the ST-HR index and the ST-HR slope.
These findings support the value of heart rate adjustment of end-exercise repolarization changes during exercise electrocardiography and demonstrate that this approach significantly improves the performance of the ST integral in identifying coronary artery disease.
- Received March 4, 1991.
- Revision received April 22, 1991.
- Accepted May 25, 1991.