Background: T-wave alternans (TWA) at microvolt level is considered as an important non-invasive risk factor for sudden death. Several methods are used to measure such repolarization variations, but each of them has some limitations. The purpose of our study is to assess the usefulness of Poincaré maps, a method based on non-linear dynamics theory, in detection of repolarization abnormalities.
Material/Methods: In 30 postinfarction patients presence of TWA in precordial ECG leads was assessed by the spectral method (SM) and by the Poincaré maps (PM). Quantitative measures of both methods: alternans voltage (AV) and alternans distance (AD) were compared using linear regression.
Results: Significant correlation between both measures (r&equals;0.92, p<0.01) was found. The value of AD≥10 µV was accepted as significant for the presence of T-wave alternans.
Conclusions: Poincaré mapping seems to be a useful and simple method for detection of TWA. The alternans distance equal or greater than 10 µV can be considered as a level determinative for the presence of TWA.

Keywords: T-wave alternans, spectral method, PoincarŽ maps