Value Of Heart Rate Adjusted ST Segment Depression In Detecting Coronary Artery Disease

Objective To assess the diagnostic values for heart rate adjusted indexs of ST segment depression (the ST segment / heart rate slope and the ST segment / heart rate hysteresis) in detecting coronary artery disease (CAD). Methods To explore the sensitivity and the specificity of ST segment / heart rate (ST/HR) slope and ST segment / heart rate (ST/HR) hysteresis in detecting CAD, Thirty-eight CAD patientes confirmed by coronary angiography and 50 healthy volunteers were examined by computer assisted ST/HR slope and ST/HR hysteresis analysis. Results the ST/HR slope in case group was significantly higher than that in normal group (P=0.0001). The sensitivity of ST/HR slope and standard exercise test electrocardiography (ECG) criteria in detecting CADwas 92.1% (35/38) versus 73.7% (28/38) (P=0.033). The specificity ,94% (47/50) versus 78% (39/50) (P=0.021). The accuracy, 93.2% (82/88) versus 76.1% (67/88) (P=0.002). The ST/HR slope in three-vessel CAD was significantly higher than that in 1-2-vessel CAD (P=0.0001). A ST/HR slope≥6.0μV·bp-1·min-1 identified three-vessel CAD with a sensitivity of 91.7% (11/12), a specificity of 61.5% (16/26) and a accuracy of 71.1% (27/38). The performance of ST/HR slope in detecting CAD was similar in men and women. The sensitivity of ST/HR hysteresis was significantly higher than that of standard exercise test ECG criteria in detecting CAD (94.7% vs 73.7% , ie 36/38 vs 28/38 , P=0.012), But the specificity of ST/HR hysteresis was significantly lower than that of standard exercise test ECG criteria in detecting CAD (54% vs 78%, ie 27/50 vs 39/50, P=0.011). The accuracy of ST/HR hysteresis and standard exercise test ECG criteria in detecting CAD was 71.6% (63/88) versus 76.1% (67/88) (P=0.493) . Conclusion These findings suggest that ST/HR slope is a good method for the diagnosis of CAD . The sensitivity , the specificity and the accuracy of ST/HR slope are significantly higher than that of standard exercise test ECG in detecting CAD. ST/HR slope can serve as reference at detecting three-vessel CAD. ST/HR hysteresis is not markedly better than standard exercise test ECG criteria at detecting CAD and adds limiteddiagnostic value to CAD.