Blackwell Publishing Journal Backfiles 1879-2005
Background: Coronary artery disease (CAD) is associated with a small but measurable amount of electrical disorganization, which may appear as temporal electrical heterogeneity on the electrocardiogram and is not visible with the low resolution, 12-lead electrocardiogram. A newly developed, multilead, high-fidelity variance cardiograph captures the heterogeneity component of the electrocardiograph signal. The subsequent analysis produces an electrical heterogeneity index (EHI) by quantifying phase-invariant electrical disorganization, which represents cardiac abnormalities that are modulated onto the measured high frequency electrocardiogram. A prospective investigation was conducted to determine the predictive accuracy of the variance cardiograph to detect clinically important CAD.Methods: Sixty-five patients (group I) with documented CAD were given the variance cardiography test, as well as 21 normal volunteers (group II). An EHI 〉; 75 from the variance cardiograph was determined to best represent a positive test for clinically important CAD.Results: Group I had a mean EHI of 89.5 ± 19.7, while group II had a mean EHI of 61.1 ± 19.1 (P 〈 0.001). The variance cardiograph had a sensitivity of 79%, a specificity of 76%, a positive predictive value of 91%, and a negative predictive value of 55%.Conclusions: These results demonstrate that analysis of the temporal electrical heterogeneity component of the electrocardiographic signal obtained by the variance cardiograph provides a new and reliable stress-free test For the detection of CAD.
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