Phonocardiography (PCG) second heart sound represents aortic-pulmonary valves closure and beginning of isovolumetric relaxation of the ventricles. Electrocardiography (ECG) T wave represents electrical repolarization of the ventricles. Ventricular electrical repolarization is known to drive ventricular mechanical relaxation. Thus, the aim of the present study was to investigate whether, in normal conditions, second heart sound onset (S2on) matches in time T-wave offset (Toff) so that S2on may be used to identify Toff. To this aim, 99 couples of simultaneously recorded short (around 30 s PCG and ECG) signals relative to normal subjects (selected from PhysioNet/CinC Challenge 2016: Training Set A) were analyzed. S2on was identified by application of our newly developed threshold-based algorithm to the median beat of the PCG envelope. Instead, Toff was identified by application of the Laguna and Thakor algorithm to the median ECG beat. Median time-distance (δt) between S2on and Toff was 5 ms (P=0.007). Thus, in normal conditions, S2on and Toff differ on average of 5 ms, whose meaning remain to be defined. Still, 5 ms is included in the Toff identification variability (of the order of tens ms) due to different Toff identification methods and electrocardiographic leads. Consequently, in normal condition, S2on may be used to estimate Toff
Second heart sound onset to identify T-wave offset / Sbrollini, Agnese; Bartoli, Marta Beghella; Agostinelli, Angela; Morettini, Micaela; Di Nardo, Francesco; Fioretti, Sandro; Burattini, Laura. - In: COMPUTING IN CARDIOLOGY. - ISSN 2325-8861. - ELETTRONICO. - 44:(2017), pp. 1-4. (Intervento presentato al convegno 44th Computing in Cardiology Conference, CinC 2017 tenutosi a Rennes, Francia nel 24-27/09/2017) [10.22489/CinC.2017.085-076].
Second heart sound onset to identify T-wave offset
Sbrollini, Agnese;Agostinelli, Angela;Morettini, Micaela;Di Nardo, Francesco;Fioretti, Sandro;Burattini, Laura
2017-01-01
Abstract
Phonocardiography (PCG) second heart sound represents aortic-pulmonary valves closure and beginning of isovolumetric relaxation of the ventricles. Electrocardiography (ECG) T wave represents electrical repolarization of the ventricles. Ventricular electrical repolarization is known to drive ventricular mechanical relaxation. Thus, the aim of the present study was to investigate whether, in normal conditions, second heart sound onset (S2on) matches in time T-wave offset (Toff) so that S2on may be used to identify Toff. To this aim, 99 couples of simultaneously recorded short (around 30 s PCG and ECG) signals relative to normal subjects (selected from PhysioNet/CinC Challenge 2016: Training Set A) were analyzed. S2on was identified by application of our newly developed threshold-based algorithm to the median beat of the PCG envelope. Instead, Toff was identified by application of the Laguna and Thakor algorithm to the median ECG beat. Median time-distance (δt) between S2on and Toff was 5 ms (P=0.007). Thus, in normal conditions, S2on and Toff differ on average of 5 ms, whose meaning remain to be defined. Still, 5 ms is included in the Toff identification variability (of the order of tens ms) due to different Toff identification methods and electrocardiographic leads. Consequently, in normal condition, S2on may be used to estimate ToffI documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
