Value Of Chronotropic Index In Identifying Coronary Artery Disease

Objective To assess the diagnostic value of chronotropic index in identifying coronary artery disease (CAD).Methods One hundred and sixty two patients with suspected CAD were referred for a routine treadmill exercise electrocardiogram and subsequently they underwent selective coronary angiography within 3 weeks. The magnitude of ST segment depression and chronotropic index were performed by a computerized ECG system. CAD was defined by coronary angiography.Results The sensitivity of chronotropic index and standard electrocardiographic test criteria in detecting CAD was 70.1% versus 60.9% (P<0.05). The specificity, 84.0% versus 73.3% (P<0.05). The accuracy, 76.5% versus 66.7% (P<0.05). The value of Kappa statistic for chronotropic index consistency in our experiment was 0.534(>0.4). The value of Kappa statistic for standard electrocardiographic test criteria consistency was 0.338(<0.4). The number of diseased vessels was correlated with the mean value of chronotropic index . The chronotropic index decreased from 0.88±0.09 in patients without coronary disease to 0.68±0.06 in those with 3 vessels involved (P<0.01). There was no significant difference in the mean value of chronotropic index between patients with 1 vessel coronary disease and those without coronary disease(P>0.05). A more closed relation was found between chronotropic index and stenosis in the right coronary artery (OR 26.21, p P<0.01).Conclusions Chronotropic index is a valuable method for the diagnosis of CAD. The sensitivity, specificity and accuracy of chronotropic index were significantly higher than those of standard electrocardiographic test criteria in identifying CAD .