PP.32.10: QT HYSTERESIS INDEX IMPROVES THE POWER OF TREADMILL EXERCISE TEST IN THE SCREENING OF CORONARY ARTERY DISEASE. (June 2015)

• Record Type: Journal Article
• Authors: Mingwei, B.; Yijie, Z.; Mingyan, D.; Hui, Z.; Yan, L.; Tuantuan, T.
• Is Part Of: Journal of hypertension. Volume 33(2015)Supplement 1
• Publication Date: 2015-06
• Subjects: Hypertension -- Periodicals; Hypertension -- Periodicals; 616.132005
• DOI: 10.1097/01.hjh.0000468704.97084.97
• Languages: English
• ISSNs: 1473-5598

Abstract

Abstract : Objective: QT hysteresis phenomenon exists in healthy subjects, and is more exaggerated in patients with coronary artery disease (CAD) and long QT syndrome. The purpose of this study is to establish an appropriate method to evaluate the magnitude of QT hysteresis and assess the value of QT hysteresis index in the treadmill exercise test (TET) in predicting CAD. Design and method: 138 subjects suspected of CAD and referred for TET and selective coronary angiography (SCA) were divided into positive (n = 61, age 55.6 ± 7.8 yr) and negative (n = 77, age 53.5 ± 6.7 yr) groups based on the SCA results. Dynamic ECGs were recorded by a Holter recorder during the TET and analyzed offline. QTp (Q-Tpeak), and QTe (Q-Tend) intervals were plotted against the corresponding RR intervals. QT/RR curves were constructed by connecting all points in sequence, and QTp and QTe hysteresis indices were calculated for each subject. Results: The QTp and QTe hysteresis indices of SCA positive group (19.3 ± 10.7 ms and 24.0 ± 12.8 ms, respectively) were significantly (P < 0.001) higher than SCA negative group (6.5 ± 6.4 ms and 7.6 ± 6.3 ms, respectively). The combination of QTe hysteresis index and conventional TET criteria had the highest sensitivity (0.831) and negative predictive values (0.806) according to the receiver operating characteristic (ROC) curves, and was an independent predictor (P = 0.038) by multivariate logistic regression analysis. Figure. No caption available. Conclusions: QTe hysteresis index enhances the specificity of predicting CAD in TET. It improves the diagnostic value of TET for CAD significantly when combined with conventional criteria.