T-end versus S2-onset in Experimental Pulmonary Hypertension in Pigs

Elisa Faaborg Rytter1, Frederik Fruergaard Jensen1, Maibritt Post1, Natasja Toftgaard Garner2, Johannes Struijk1, Benedict Kjærgaard3, Noemi Giordano4, Samuel Emil Schmidt1
1Aalborg University, 2Aalborg Universitet, 3Aalborg University Hospital, 4Politecnico di Torino


Abstract

Pulmonary hypertension (PH) can lead to changes of the timing of pulmonary valve closure. The aim of this study was to investigate if deviations of the second heart sound (S2) in seismocardiograms (SCG) relative to the end of the T-wave (T-end) in the ECG can detect PH. Methods were developed to detect T-end in the ECG and start of S2 (S2-onset) in the SCG. The data were obtained from an animal model, where pigs were induced with PH by exposing them to hypoxemia and hypercapnia. Each intervention recording was compared with the corresponding baseline recording for each animal. The tests were performed on 10 pigs, where 17 recordings of hypoxemia and 16 recordings of hypercapnia were included. The results of S2-onset to T-end show that S2-onset came 34 ms earlier for baseline and 65 ms earlier for hypercapnia(p=0.01). S2-onset came 33 ms earlier for baseline before hypoxemia and 42 ms earlier during hypoxemia (p=0.39). The figure represents this change in S2-onset compared to T-end and RV systolic pressure. Thus, a significant change of S2-onset compared with T-end was observed for pigs induced with hypercapnia. The results show potential for further research of the correlation between S2-onset and T-end during PH.