Fetal QRS extraction based on wavelet analysis and pattern matching

A high precision method for fetal QRS complex extraction from the abdominal ECG is presented. The method is based on a wavelet multiresolution decomposition and a pattern matching procedure. The wavelet analysis allowed the elimination of detail signals that did not have maternal and fetal QRS frequency components and it also allowed maternal and fetal complexes homogenization. The existence and position of a fetal QRS immersed in a maternal QRS was determined by correlating the maternal complex with a set of cases that represent all possible fetal occurrences. The method was able to detect all immersed fetal QRS complexes in 5 real signals. Non significant differences for the position of 202 extracted fetal complexes were found on simulated signals. This method introduces a new approach resulting in excellent fetal QRS extraction and maternal QRS cancellation