Aims: The diagnosis of pulmonary hypertension (PH) is often delayed in the course of the disease, contributing to its high mortality rate. Seismocardiography (SCG) is a noninvasive measurement of cardiac function, which could potentially be used for early detection and monitoring of PH. This study aimed to assess the potential of SCG in detecting PH in porcine models.
Methods: ECG and SCG data were collected from 10 porcine models undergoing right heart catheterization. PH was induced with hypoxemia (21 sessions) or hypercapnia (20 sessions). The SCG-signals were analyzed at baseline, hypoxemia, and hypercapnia. The SCG-signal was segmented into separate heartbeats using an ECG-based segmentation model and a fiducial point detection algorithm was used to identify, systolic and diastolic time intervals isovolumetric contraction time (IVCT), isovolumic relaxation time (IVRT), and left ventricular ejection time (LVET). All intervals are analyzed as a proportion of the RR interval, to adjust for changes in heart rate.
Results: During hypoxemia, the right ventricle systolic blood pressure (RVSBP) increased from 30.97mmhg (SD 8.04) at baseline to 40.77mmhg (SD 10.35) (p= 0.001). During hypercapnia, RVSBP increased from 29.2mmhg (SD 9.94) at baseline to 53.04mmhg (SD 19.63) (p= 0.001). The SCG-signals showed, in hypoxemia, a significant prolongation (in % relative to the RR-interval) in IVCT, from 4.48% (SD 1.36) to 5.58% (SD 1.88) (p= .0143), and IVRT, from 7.33% (SD 1.72) to 9.64% (SD 3.84) (p= .001). In hypercapnia, LVET significantly increased from 34.63% (SD 6.04) to 40.96% (SD 10.80) (p= .0247), IVRT increased from 7.33% (SD 1.73) to 11.92% (SD 5.10) (p= .001) and IVCT increased from 4.18% (SD 1.07) to 6.61% (SD 2.11) (p= .001).
Conclusion: This study found an increase in the normalized SCG time intervals for IVCT and IVRT in porcine models with induced PH. Thereby, indicating a potential of SCG to capture PH.