2. INSTITUTE OF BIOMEDICAL ENGINEERING DEPARTMENT OF ENGINEERING SCIENCE UNIVERSITY OF OXFORD

3.  S1– Atrial contraction  S2–Ventricular contraction  S3 – Blood returning to the ventricle  S4 – Ventricle is too full to contain the blood Normal Abnormal S1 + S2Lub - Dub S1 + S2 + S3 Ken – Tuck – Y S4 + S1 + S2 Ten – Nes - See Animation of heart valves opening and closing with sound “LUB”“DUB”

4.  How heart sounds change during illness http://commons.wikimedia.org/wiki/File:Phono cardiograms_from_normal_and_abnormal_h eart_sounds_with_pressure_diagrams.png

5.  How to record heart sounds?  Acoustic Stethoscope Chest piece transmits sound to the listener via air-filled hollow tubes

6.  How to record heart sounds?  Electronic Stethoscope - microphone Place a microphone in the chestpiece Moving magnetic coil  electrical signal

7.  How to record heart sounds?  Electronic Stethoscope - piezoelectric Connect one end of the crystal with the diaphragm Plates squeezed  electric signal

8.  How to record heart sounds?  Electronic Stethoscope - capacitor Body Conductive plates Distance between plates Electromagnetic diaphragm with conductive inner surface Vibrations  electric signal

9.  Phone apps Ascultation – library of heart sounds iStethoscope – turn your iPhone into a stethoscope Plug-in stethoscope

10.  Other uses of stethoscopes:

11. Any Questions?