A Novel Method to Estimate Baroreflex Sensitivity Based ... - IEEE Xplore

Proceedings of the IEEE-EMBS International Conference on Biomedical and Health Informatics (BHI 2012) Hong Kong and Shenzhen, China, 2-7 Jan 2012

A Novel Method to Estimate Baroreflex Sensitivity Based on Pulse

Transit Time Qing Liu, Carmen, C. Y. Poon, and Yuan-ting Zhang

domain and the sequence method in the time domain are two

Abstract- Baroreflex sensitivity (BRS) has emerged as a prognostic

factor

in

cardiology.

Spontaneous

main categories of spontaneous techniques for measuring

sequence

technique is one of the most commonly used methods in

BRS.

measuring BRS. The technique requires continuous beat-to-beat blood

pressure

(BP)

which,

however,

cannot

be

Continuous measurement of electrocardiogram (ECG) and

obtained

BP enables the spontaneous BRS estimation. Nevertheless,

conveniently. Considering that pulse transit time (PTT) is

state-of-art BP meters can only provide intermittent BP

inversely related to BP and can be easily and continuously acquired

from

electrocardiogram

(ECG)

reading or use an intlatable cuff which limits the size and

and

photoplethysmogram (PPG), we proposed in this study a novel

power

method that estimates BRS from PTT based on the sequence

measurement still remains a challenge, making acquisition of

technique

BRS difficult. Alternatively, pulse transit time (PTT) which is

with

low-pass

filtering.

The

experiment

was

conducted on 25 healthy subjects from whom continuous BP,

consumption

of

the

devices.

Continuous

BP

the time taken for a pressure pulse wave to travel along the

PTT and R-R interval (RRI) of ECG were obtained before,

artery and arrive at the periphery has shown high correlation

during and after drinking 400ml of water. SBP-based BRS and PTT-based BRS were separately calculated. The results showed

with BP and given promising results in continuous BP

high correlations between these two BRS estimates in all

measurement

situations (correlation coefficient y=0.90, 0.70 and 0.81 before,

beat-to-beat

during and after drinking respectively). Furthermore, results

photoplethysmogram (PPG) which both can be achieved by

from both methods indicate that BRS increased significantly

B

of

pressure

(BP)

[1].

Baroretlex

of

on

ECG

a

and

from BP and HR. In addition, based on previous literatures [5, would induce variations in BP.

risk of developing essential hypertension [2]. Alterations of in

acquired

6], water drinking is used in this study as a daily activity that

interval to the change of BP is of clinical relevance in

changes

be

a new method to estimate BRS from PTT and HR using the

predicting the risk of sudden cardiac death and evaluating the indicate

can

measurement

sequence method and compare the estimates to those obtained

sensitivity (BRS) which retlects the response of an inter-beat

BRS

PTT

technique. Therefore, the objective of this study is to propose

INTRODUCTION

blood

from

used as a surrogate of BP for BRS assessment using sequence

AROREFLEX is a basic mechanism for the short-term regulation

Since

wearable devices, it is proposed in this study that PTT can be

(p