Detection of QRS-duration in Chagas´ patients with wavelets

Individuals with Chagas´ disease develop abnormal ventricular conduction patterns which can be measured with late potentials (LP) measured from signal-averaged ECG (SAECG). The end-point of the QRS (and thus total QRS duration-TQRSD) must be accurately detected in order to determine if an individual exhibits LP. The authors have found that the standard time-domain method under estimates TQRSD in noisy signals. Their hypothesis is that the TQRSD can be more accurately determined from the wavelet-transformed SAECG in a neural network in noisy data. The authors compared the TQRSD measured by experts with the standard method and the authors´ proposed method. The results of the proposed method were highly correlated with those from the experts (Slope=0.94, Int.=7.1 ms, R=0.94). The proposed method reduced the difference between the automatically, determined and manually determined values by 57%. It is concluded that the proposed method has good potential to help automate the analysis of cardiac conduction anomalies in chagasic patients