Automatic SVM classification of sudden cardiac death and pump failure death from autonomic and repolarization ECG markers

作者：Ramirez Julia^*; Monasterio Violeta; Minchole Ana; Llamedo Mariano; Lenis Gustavo; Cygankiewicz Iwona; Bayes de Luna Antonio; Malik Marek; Pablo Martinez Juan; Laguna Pablo; Pueyo Esther

来源：Journal of Electrocardiology, 2015, 48(4): 551-557.

DOI：10.1016/j.jelectrocard.2015.04.002

• SCD
• Pump failure death
• Support vector machine
• ECG
• CHF
• Tpc/RR dynamicity
• T-wave altemans
• Heart rate turbulence

Background: Considering the rates of sudden cardiac death (SCD) and pump failure death (PFD) in chronic heart failure (CHF) patients and the cost-effectiveness of their preventing treatments, identification of CHF patients at risk is an important challenge. In this work, we studied the prognostic performance of the combination of an index potentially related to dispersion of repolarization restitution (Delta alpha), an index quantifying T-wave alternans (IAA) and the slope of heart rate turbulence (TS) for classification of SCD and PFD.
Methods: Holter ECG recordings of 597 CHF patients with sinus rhythm enrolled in the MUSIC study were analyzed and Delta alpha, IAA and TS were obtained. A strategy was implemented using support vector machines (SVM) to classify patients in three groups: SCD victims, PFD victims and other patients (the latter including survivors and victims of non-cardiac causes). Cross-validation was used to evaluate the performance of the implemented classifier.
Results: Delta alpha and IAA, dichotomized at 0.035 (dimensionless) and 3.73 mu V, respectively, were the ECG markers most strongly associated with SCD, while TS, dichotomized at 2.5 ms/RR, was the index most strongly related to PFD. When separating SCD victims from the rest of patients, the individual marker with best performance was Delta alpha >= 0.035, which, for a fixed specificity (Sp) of 90%, showed a sensitivity (Se) value of 10%, while the combination of Delta alpha and IAA increased Se to 18%. For separation of PFD victims from the rest of patients, the best individual marker was TS <= 2.5 ms/RR, which, for Sp = 90%, showed a Se of 26%, this value being lower than Se = 34%, produced by the combination of Delta alpha and TS. Furthermore, when performing SVM classification into the three reported groups, the optimal combination of risk markers led to a maximum Sp of 79% (Se = 18%) for SCD and Sp of 81% (Se = 14%) for PFD.
Conclusions: The results shown in this work suggest that it is possible to efficiently discriminate SCD and PFD in a population of CHF patients using ECG-derived risk markers like Delta alpha, TS and IAA.

• 出版日期2015-8