doi:10.1016/j.compbiomed.2022.105304engBukhari, Hassaan A.Sánchez, CarlosSrinivasan, SabarathinamPalmieri, FlavioPotse, MarkLaguna, PabloPueyo, EstherEstimation of potassium levels in hemodialysis patients by T wave nonlinear dynamics and morphology markersART-2022-128265Noninvasive screening of hypo- and hyperkalemia can prevent fatal arrhythmia in end-stage renal disease (ESRD) patients, but current methods for monitoring of serum potassium (K+) have important limitations. We investigated changes in nonlinear dynamics and morphology of the T wave in the electrocardiogram (ECG) of ESRD patients during hemodialysis (HD), assessing their relationship with K+ and designing a K+ estimator. Methods: ECG recordings from twenty-nine ESRD patients undergoing HD were processed. T waves in 2-min windows were extracted at each hour during an HD session as well as at 48 h after HD start. T wave nonlinear dynamics were characterized by two indices related to the maximum Lyapunov exponent (¿t, ¿wt) and a divergence-related index (¿). Morphological variability in the T wave was evaluated by three time warping-based indices (dw, reflecting morphological variability in the time domain, and da and daNL, in the amplitude domain). K+was measured from blood samples extracted during and after HD. Stage-specific and patient-specific K+ estimators were built based on the quantified indices and leave-one-out cross-validation was performed separately for each of the estimators. Results: The analyzed indices showed high inter-individual variability in their relationship with K+. Nevertheless, all of them had higher values at the HD start and 48 h after it, corresponding to the highest K+. The indices ¿ and dw were the most strongly correlated with K+ (median Pearson correlation coefficient of 0.78 and 0.83, respectively) and were used in univariable and multivariable linear K+ estimators. Agreement between actual and estimated K+ was confirmed, with averaged errors over patients and time points being 0.000 ± 0.875 mM and 0.046 ± 0.690 mM for stage-specific and patient-specific multivariable K+ estimators, respectively.ariability allow noninvasive monitoring of [K+] in ESRD patients. Significance: ECG markers have the potential to be used for hypo- and hyperkalemia screening in ESRD patients2022http://zaguan.unizar.es/record/11208710.1016/j.compbiomed.2022.105304http://zaguan.unizar.es/record/112087oai:zaguan.unizar.es:112087info:eu-repo/grantAgreement/ES/DGA-FSE/LMP124-18info:eu-repo/grantAgreement/EC/H2020/764738/EU/Personalised In-Silico Cardiology/PICThis project has received funding from the European Union’s Horizon 2020 research and innovation program under grant agreement No H2020 764738-PICinfo:eu-repo/grantAgreement/ES/MICINN-FEDER/PID2019-104881RB-I00info:eu-repo/grantAgreement/ES/MICINN-FEDER/PID2019-105674RB-I00Computers in biology and medicine 143 (2022), 105304 [13 pp]by-nc-ndhttp://creativecommons.org/licenses/by-nc-nd/3.0/es/info:eu-repo/semantics/openAccess