D EVELOPMENT OF A D IGITAL A USCULTATION D EVICE FOR REAL TIME M URMUR D ETECTION Tanvi Kalra 1 , Abhinav 2 and Sneh Anand 2 1 - Department of Biomedical Engineering, Rayat & Bahra Institute of Engineering & Bio-Technology, Punjab 2 - Centre for Biomedical Engineering, Indian Institute of Technology – Delhi

NEED OF THE SYSTEM



Training required – detection of subtle heart sounds



Ambient noise in the hospital



Reliable diagnosis



Portable device

INTRODUCTION

    development of a digital auscultation device second order butterworth filter reduce the ambient noise integration of 1. traditional stethoscope 2. an electret microphone      3. an amplifier circuit software - audacity real time plotting detection of murmurs diagnosing of heart sounds battery powered

FEATURES

1. Amplification 2. Clear audibility 3. Volume control 4. Noise removal 5. Real time plotting

BLOCK DIAGRAM

Figure 1: block diagram of the digital auscultation device

CONNECTIONS

Figure 2: (a) – traditional stethoscope, (b) – hardware circuit, (c) – compatible earphones, (d) – connecting cable, (e) – plotted heart sounds.

HARDWARE

 Electret microphone – frequency response    (30 Hz - 10 KHz) Amplifier circuit – linear op-amps  - gain (20) Buffers – removing the loading effects. Filters – 2 nd order butterworth band pass filter - frequency range (50 Hz – 600 Hz) - diaphragm mode Output – potentiometers (volume and gain control) 1. Jack 1 – Audible signal 2. Jack 2 – Plotted signal

F

EATURES

& B

ENEFITS

    Varying gain AUDACITY (compatible) Beneficial device for cardiologists Easily diagnose HEART’s conditions

S NAPSHOT OF THE AUSCULTATION

Figure 3: heart sounds of healthy and unhealthy subjects

REFERENCES

1.

Heart Sound Measurement and Analysis System with Digital Stethoscope Haibin Wang; Jian Chen; Yuliang Hu; Zhongwei Jiang; Choi Samjin; Biomedical Engineering and Informatics, 2009. BMEI '09.

2nd International Conference on Digital Object Identifier: 10.1109/BMEI.2009.5305287

Publication Year: 2009 , Page(s): 1 - 5 2. The embedded digital stethoscope uses the adaptive noise cancellation filter and the type I Chebyshev IIR bandpass filter to reduce the noise of the heart sound Ying-Wen Bai; Chao-Lin Lu; Enterprise networking and Computing in Healthcare Industry, 2005. HEALTHCOM 2005. Proceedings of 7th International Workshop on Publication Year: 2005 , Page(s): 278 - 281 3. Design and implementation of a remote embedded DSP stethoscope with a method for judging heart murmur Ying-Wen Bai; Cheng-Hsiang Yeh; Instrumentation and Measurement Technology Conference, 2009. I2MTC '09. IEEE Digital Object Identifier: 10.1109/IMTC.2009.5168706

Publication Year: 2009 , Page(s): 1580 - 1585 4. Segmentation of heart sound recordings from an electronic stethoscope by a duration dependent Hidden-Markov Model Schmidt, S.E.; Toft, E.; Holst-Hansen, C.; Graff, C.; Struijk, J.J.; Computers in Cardiology, 2008 Digital Object Identifier: 10.1109/CIC.2008.4749049

Publication Year: 2008 , Page(s): 345 - 348 5. Analysis and classification of heart sounds and murmurs based on the instantaneous energy and frequency estimations Sharif, Z.; Zainal, M.S.; Sha'ameri, A.Z.; Salleh, S.H.S.; TENCON 2000. Proceedings Volume: 2 Digital Object Identifier: 10.1109/TENCON.2000.888404

Publication Year: 2000 , Page(s): 130 - 134 vol.2 6.

Recursive least squares adaptive noise cancellation filtering for heart sound reduction in lung sounds recordings Gnitecki, J.; Moussavi, Z.; Pasterkamp, H.; Engineering in Medicine and Biology Society, 2003. Proceedings of the 25th Annual International Conference of the IEEE 10.1109/IEMBS.2003.1280403

Publication Year: 2003 , Page(s): 2416 - 2419 Vol.3 Volume: 3 Digital Object Identifier:

T

HANK YOU ANY QUESTIONS

..?