Intersubject variability and intrasubject reproducibility of 12-lead ECG metrics: Implications for human verification.
Electrocardiogram (ECG) biometrics is an advanced technology, not yet covered by guidelines on criteria, features and leads for maximal authentication accuracy.



This study aims to define the minimal set of morphological metrics in 12-lead ECG by optimization towards high reliability and security, and validation in a person verification model across a large population.



A standard 12-lead resting ECG database from 574 non-cardiac patients with two remote recordings (>1year apart) was used. A commercial ECG analysis module (Schiller AG) measured 202 morphological features, including lead-specific amplitudes, durations, ST-metrics, and axes. Coefficient of variation (CV, intersubject variability) and percent-mean-absolute-difference (PMAD, intrasubject reproducibility) defined the optimization (PMAD/CV→min) and restriction (CV<30%) criteria for selection of the most stable and distinctive features. Linear discriminant analysis (LDA) validated the non-redundant feature set for person verification.



Maximal LDA verification sensitivity (85.3%) and specificity (86.4%) were validated for 11 optimal features: R-amplitude (I,II,V1,V2,V3,V5), S-amplitude (V1,V2), Tnegative-amplitude (aVR), and R-duration (aVF,V1).
Institute of Biophysics and Biomedical Engineering, Bulgarian Academy of Sciences, Bulgaria. Electronic address: irena@biomed.bas.bg.
Irena
I
Jekova
Institute of Biophysics and Biomedical Engineering, Bulgarian Academy of Sciences, Bulgaria.
Vessela
V
Krasteva
SCHILLER AG, Research and Signal Processing, Baar, Switzerland.
Remo
R
Leber
SCHILLER AG, Research and Signal Processing, Baar, Switzerland.
Ramun
R
Schmid
University Hospital of Basel, Cardiovascular Research Institute (CRIB), Basel, Switzerland.
Raphael
R
Twerenbold
University Hospital of Basel, Cardiovascular Research Institute (CRIB), Basel, Switzerland.
Christian
C
Müller
University Hospital of Basel, Cardiovascular Research Institute (CRIB), Basel, Switzerland.
Tobias
T
Reichlin
SCHILLER AG, Research and Signal Processing, Baar, Switzerland; University Hospital of Basel, Cardiovascular Research Institute (CRIB), Basel, Switzerland.
Roger
R
Abächerli
D016002:Discriminant Analysis; D004562:Electrocardiography / Q000379:methods / Q000592:standards* / Q000706:statistics & numerical data*; D005060:Europe; D006339:Heart Rate / Q000502:physiology*; D000070276:Heart Rate Determination / Q000379:methods / Q000592:standards* / Q000706:statistics & numerical data*; D006801:Humans; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
ECG biometrics; ECG diagnostic morphological features; Linear discriminant analysis; Optimization criteria; Person authentication