Time intervals (CTI) are important parameters that have been used for quantification of the performance of the heart and are grouped into systolic and diastolic time intervals. The systolic time intervals include the electro-mechanical systole, left ventricular ejection time (LVET), pre-ejection period (PEP) and isovolumetric-contraction time. Systolic time interval were originally measured using electrocardiogram (ECG), phonocardiogram (PCG) and carotid pulse.

The SCG signal is measured by placing an accelerometer on the torso which captures the induced vibration of the heart propagated to the surface of the chest. The feasibility of using seismocardiogram (SCG), in conjunction with ECG, for finding cardiac time intervals was first investigated in 1990’s and has also been recently verified. An important challenge, however, is proper annotation of fiducial points on SCG which is one of the focus research in our lab.

These timings have been previously compared to echocardiogram and impedance cardiogram.