Elsevier

American Heart Journal

Volume 134, Issue 4, October 1997, Pages 647-655
American Heart Journal

Accuracy of heart rate–adjusted ST segments in populations with and without posttest referral bias,☆☆

https://doi.org/10.1016/S0002-8703(97)70047-4Get rights and content

Abstract

We compared the accuracy of the ST segment/heart rate (STHR) index and slope to standard criteria (≥1 mm horizontal/downsloping ST-segment depression at J + 60 msec) in 1358 patients (152 underwent angiography). All exercise tests used the Cornell protocol and computer measurements of maximum ST-segment depression at J + 60 msec. Test accuracy was determined for the entire group with a probability-based method. Thresholds with equal specificity to standard criteria were determined. By using only patients who underwent angiography, neither STHR index nor slope was more accurate than standard criteria (maximum sensitivity: standard criteria, 42%; STHR index, 51%; STHR slope, 40%). However, by using the entire group, both STHR index and slope were more accurate than standard criteria, but only STHR index achieved statistical significance (maximum sensitivity: standard criteria, 31%; STHR index, 60%; STHR slope, 47%). We conclude that heart rate–adjusted ST-segment criteria are more accurate than standard ST-segment criteria. A lack of demonstration of improved accuracy of STHR index and slope only occurs in patients affected by posttest referral bias. (Am Heart J 1997;134:647-55.)

Section snippets

Patients

The population was composed of all patients referred by either their primary care physician or cardiologist to the exercise laboratory with suspected coronary artery disease between January 1993 and July 1995. Patients with a history of prior myocardial infarction or coronary angiography, patients receiving digitalis, and those with uninterpretable exercise electrocardiograms, including those with left bundle branch block, left ventricular hypertrophy, Wolff-Parkinson-White syndrome, and other

Population

Table I lists the clinical and exercise characteristics of the 1358 patients included in this study and the subgroups that did and did not undergo coronary angiography. The angiographic subgroup (n = 152) affected by posttest referral bias was very different from the subgroup of 1206 patients who did not undergo angiography. The angiographic group was older and had a greater frequency of angina, hypercholesterolemia, and diabetes. These differences are summarized by considering the significant

Discussion

The topic of heart rate adjustment of ST segments has generated considerable controversy.17, 18, 19, 20, 21, 22 The points of contention have focused on methodologic details and patient population selection. Okin and Kligfield,12 the principal proponents of the method, have published explicit guidelines concerning what they feel are the methodologic factors that affect the performance of heart rate adjustment. This study precisely followed those methodologic recommendations to perform a fair

Acknowledgements

I thank Christine Morise for entering data into a computer spreadsheet.

References (23)

Cited by (0)

Reprint requests: Anthony Morise, MD, Section of Cardiology, HSC-South, Morgantown, WV 26506-9157.

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