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

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<br/>(T-end) in the ECG can detect PH.<br/>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 (n=8) were induced with PH by exposing them to hypoxemia (n=17) and hypercapnia<br/>(n=16). 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).<br/>Thus, a significant change of S2-onset compared with Tend was observed for pigs induced with hypercapnia.