Abstract

OROSCO, L.L.  and  LACIAR, E.. Analysis of ventricular late potentials in high resolution ecg records by time-frequency representations. Lat. Am. appl. res. [online]. 2009, vol.39, n.3, pp.255-260. ISSN 0327-0793.

This study proposes the application of different linear and quadratic Time-Frequency Representations (TFR) for the analysis of Ventricular Late Potentials (VLP) in High-Resolution Electrocardiographic (HRECG) records. The TFR used here were Short-Time Fourier Transform (STFT), Wigner-Ville (WV) and Choi-Williams (CW) distributions. These techniques were used to evaluate the risk of Ventricular Tachycardia (VT) in post-infarction patients. For comparison, the same analysis was made on HRECG records of subjects presenting Low Arrhythmia Risk (LAR). For all TFR and both populations, two indexes on the Time-Frequency (T-F) plane were considered: a) Energy of VLP normalized with respect to the total energy of the beat (EN_TOTAL) and b) Energy of VLP normalized with respect to the energy of QRS complex (EN_QRS). The results indicate that the two T-F indexes of the LAR group show higher mean values than those of the VT group, for all TFR used. In addition, the EN_QRS index for the WV distribution obtained the best valuation as a diagnostic test, showing the highest sensitivity and specificity values. It can be concluded that T-F analysis of HRECG is a promissory technique of diagnosis to identify post-infarct patients with high risk of VT.

Keywords : Ventricular Late Potentials; High-Resolution ECG; Time-Frequency Representations.

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