REPRODUCIBILITY OF THE SPECTRAL TURBULENCE ANALYSIS OF THE SIGNAL-AVERAGED ELECTROCARDIOGRAM

Spectral turbulence analysis (STA) of the signal-averaged electrocardi ogram (SAECG) is a recently technique to identify patients with ventri cular tachycardia as well as patients at risk for arrhythmic events af ter acute myocardial infarction (MI). The short-term reproducibility o f this technique has been previously reported; our study evaluates the reproducibility of STA by shifting the reference points. Twenty patie nts with acute MI were recruited. SAECG was recorded 13 days after ons et of the acute MI. Unfiltered data were transferred and analyzed by p ersonal computer software for spectral turbulence analysis according t o the standard condition; reference points of the segment of interest were shifted from QRS offset - 10 ms and QRS onset - 10 ms to QRS offs et + 10 ms and QRS onset + 10 ms, step 2 ms. Thus, 10 analyses were co mputed. Reproducibility of the results was calculated using the coeffi cient of variation (CV) and the relative error (RE). The reproducibili ty of the classification (RC) was defined as the percentage of the ide ntical classification compared with the standard segment. CV of the in tersegment correlation standard deviation was statistically higher tha n the other parameters regardless of the lead considered. RE was not d ifferent in each parameter and in each lead. RC was > 90% in all param eters, except in spectral entropy which showed an RC > 80%. Reproducib ility of the STA introducing a temporal shift in the analyzed segments was high in all considered parameters.