T-wave alternans (TWA) is a variation phenomenon characterized by beat to beat alternation in the morphology and/or amplitude of the T-wave of electrocardiographic. Traditional frequency spectral method(SM) uses the power spectrum at the 0.5 cycle/beat frequency to detect TWA

however

the results are affected by the alignment strategy during detection. Therefore

the work researches on the peak alignment and dot-product alignment affecting TWA detection based on the spectral method and provides the optimum alignment strategy. The research proves that the amplitude based on dotproduct alignment estimates TWA more accurately.