Development of a Digital Auscultation Device for real time Murmur Detection

1. Development of a Digital Auscultation Device for real time Murmur Detection Tanvi Kalra1, Abhinav2 and Sneh Anand2 1 - Department of Biomedical Engineering, Rayat & Bahra Institute of Engineering & Bio-Technology, Punjab 2 - Centre for Biomedical Engineering, Indian Institute of Technology – Delhi

2. NEED OF THE SYSTEM • Training required – detection of subtle heart sounds • Ambient noise in the hospital • Reliable diagnosis • Portable device

3. 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

4. features • Amplification • Clear audibility • Volume control • 4. Noise removal • 5. Real time plotting

5. BLOCK DIAGRAM Figure 1: block diagram of the digital auscultation device

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

7. hardware • Electret microphone – frequency response • (30 Hz - 10 KHz) • Amplifier circuit – linear op-amps • - gain (20) • Buffers – removing the loading effects. • Filters – 2nd 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

8. Features & Benefits • Varying gain • AUDACITY (compatible) • Beneficial device for cardiologists • Easily diagnose HEART’s conditions

9. Snapshot of the auscultation Lubb Dup  Figure 3: heart sounds of healthy and unhealthy subjects

10. 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 Volume: 3 Digital Object Identifier: 10.1109/IEMBS.2003.1280403Publication Year: 2003 , Page(s): 2416 - 2419 Vol.3

11. Thank youany questions..?