Estimation of pulse arrival time using impedance plethysmogram from body composition scales

Long-term periodic monitoring of cardiovascular function in unobtrusive way has been a challenge in sensor research lately. This work presents the investigation of the method for pulse arrival time (PAT) estimation using body composition scales. It employs the electrocardiogram and the impedance plethysmogram (IPG) which are recorded from palm and plantar electrodes already integrated into body composition scales. Four subjects were involved in the experiment. The IPG was acquired from a single-foot and foot-to-foot and compared to the reference method — photoplethysmography. The range of correlation coefficient obtained in different methods varied from 0.7 to 0.94 showing that small PAT variations can be tracked using the IPG signals. Such results suggest that body composition scales could be supplemented with additional parameter for the assessment of arterial stiffness. This function will make them truly multi-parametric device for periodic health monitoring at home.

I. Introduction

Arterial stiffness is recognized as an important contributor to the development of cardiovascular diseases. Central (aortic) stiffness is highlighted because of its independent predictive value for all-cause and cardiovascular mortalities, coronary events, fatal strokes in elderly subjects and patients with end-stage renal disease, hypertension and impaired glucose tolerance [1]. Meanwhile, the importance of peripheral (especially lower-limbs) stiffness is underestimated although it is involved in the development of peripheral artery disease [2] and diabetic peripheral neuropathy [3]. Therefore it is important to include a parameter, which is capable to assess central and peripheral stiffness and at the same time which is non-invasive and convenient enough to become part of longterm periodic monitoring of patients with chronic diseases.