US Patent:
20050010124, Jan 13, 2005
Inventors:
Jean Couderc - Pittsford NY, US
Wojciech Zabera - Rochester NY, US
International Classification:
A61B005/0402
Abstract:
A device for the analysis of the altemans cycle to cycle and/or the variability of the venticular repolarization wave in an ECG signal. This device extracts from an ECG signal, for each cardiac beat, a temporal segment of T samples of the ventricular repolarization wave, considered as from a moment t following a predetermined temporal origin. These T samples are memorized for B consecutive beats considered starting from the bbeat of the ECG signal, so as to select and memorize a two-dimensional aggregate (C) of T×B contiguous samples of signal in space time-beats. A factor of local variance Var(C), measuring the variance of the signal level of the samples inside the aggregate, is then evaluated. Then the square root of this local variance factor is obtained and weighted by a factor of local altemans W(C) varying between a minimum, corresponding to the complete absence of altemans, and a maximum corresponding to a permanent and recurring alternans on all the beats of the aggregate. The device delivers at the output an index of alternans and variability TVarfunction, for a given beat, local variance factor weighted by the factor of local altemans.