Age and Habitus Adjustment of ECGCriterion Improves Detection of LVH as

Shown by Fuzzy ROC Curves

Gregory Campbell, PhD, James E. Norman, PhD, Daniel Levy, MD, andJames J. Bailey, MD

The "Cornell" ECGvoltage. defined as the sum ofvoltages for the R-wave of the aVL lead and the S­wave of the V3 lead. has been shown to be a relativelyefficient predictor of left ventricular hypertrophy(LVH). ECG voltages and echocardiographically de­rived left ventricular masses (LVM) have beenrecorded for 1,885 women and 1,494 men of theFramingham study cohorts and used to calculate sex­specific linear regressions of height-adjusted LVM(LVMH) on Cornell voltage, age. and body-massindex (BMI) or habitus. The results permit a simple

From the National Institutes of Health. Bethesda. Maryland.This article was prepared by US Government employees and is

not subject to copyright.

sex-specific age and BMI adjustment of the Cornellvoltage criterion that improves its overall perfor­mance as evidenced by a comparison of the areasunder the receiver-operator characteristic (ROC)curves for the adjusted and unadjusted voltages. Theapplication of the "fuzzy" set concept to the assign­ment of individual subjects to normal or LVH cate­gories based on the value of their LVMH permits theinclusion of all subjects in the derivation of the ROCcurves. A "bootstrap" technique based on repeatedsampling of the LVMHlvoltage data provides a sig­nificance test of the differences between the areasbeneath the ROCcurves for adjusted and unadjustedvoltages. Using this approach. we have shown thatthe improvement is highly significant (p <0.0000001) .

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