A new approach for blood pressure estimation based on phonocardiogram

Continuous and non-invasive measurement of blood pressure (BP) is of great importance particularly for patients in critical state. To achieve continuous and cuffless BP monitoring, pulse transit time (PTT) has been reported as a potential parameter. Nevertheless, this approach remains very sensitive, cumbersome and disagreeable in ambulatory measurement. This paper proposes a new approach to estimate blood pressure through PCG signal by exploring the correlation between PTT and diastolic duration (S21). In this purpose, an artificial neural network was developed using as input data: (systolic duration, diastolic duration, heart rate, sex, height and weight). According to the NN decision, the mean blood pressure was measured and consequently the systolic and the diastolic pressures were estimated. The proposed method is evaluated on 37 subjects. The obtained results are satisfactory, where, the error in the estimation of the systolic and the diastolic pressures compared to the commercial blood pressure device was in the order of 6 .48 ± 4.48 mmHg and 3 .91 ± 2.58 mmHg, respectively, which are very close to the AAMI standard, 5 ± 8 mmHg. This shows the feasibility of estimating of blood pressure using PCG.

The follow-up value of D/S ratio in CHF patients with treatment / 重庆医学

Objective To explore the follow-up value of phonocardiogram D/S ratio in CHF patients with treatment.Methods Forty-eight CHF patients who had never under-went regular treatment were collected in our hospital,given the regular anti-heart failure treatment for 3 months.NYHA heart failure classification,resting heart rate(RHR),and D/S ratio of phonocardiogram were recorded,six-minutes walk distance(6MWD),Left ventricular end diastolic diameter(LVEDd),the left ventricular ejection(LVEF) were tested before and after treatment.After 3-month treatment,the resting heart rate 65 times as the watershed,the patients were classified into two groups:one was up to standard,and the other was not up to standard.D/S ratio,RHR,6MWD,LVEDD,LVEF and the improvement of the heart function were compared between the two group.Results Exception the resting heart rate,the in-dicators had no significant improvement in the group of not up to standard compared with the before treatment,and D/S ratio, 6MWD,LVEF was improved significantly after three months treatment(P <0.05).In the group of up to standard,the D/S ratio was improved significantly after one months treatment(P <0.05),while after three months treatment all indicators were improved significantly(P <0.05).Comparison between the two groups,the RHR,D/S ratio were significantly improved(P <0.05 ),LVEF was significantly improved after three months treatment(P <0.05).At the same time,the D/S ratio,6MWD and NYHA classifica-tion of cardiac function was significant negatively correlated(P <0.05).Conclusion The D/S ratio could reflect heart functional im-provements in patients with CHF after anti-heart failure treatment,and it could reflect the heart functional improvement earlier and more significant in the group up to standard,it has a good clinic follow-up value in CHF patients with anti-heart failure treatment.