Since multivariate modeling requires lower (more sensitive) dichotomy limits the following will be used: spectral TWA positivity will be defined as a non-negative test. SA-ECG QRS width >104 msec will be labeled as abnormal. For HRV, SDNN values <105 msec will be considered abnormal. For BRS, values <6.1 msec per mmHg will indicate impairment. For HRT abnormalities in T-onset & / or T-slope will be considered abnormal. Receiver operating characteristic curves will be used to identify a cut-point for modified moving average TWA.