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ScilabTEC 2015 - Inria


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"Cardiovascular wave analysis module for Scilab"
By Serge Steer, Inria for ScilabTEC 2015

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ScilabTEC 2015 - Inria

  1. 1. Cardiovascular wave analysis  module for Scilab Serge Steer
  2. 2. The heart : a pump Toorgans O2 To the lungs From the lungs O2 Fromorgans Ventricular systole (contraction): ● isovolumic contraction ➢ closes the atrioventricular valves ➢ opens sigmoid valves ● ejection Ventricular diastole (relaxation) ● isovolumic relaxation ➢ Opens the atrioventricular valves ● filling ➢ Fast ➢ Slow ➢ Atrial systole
  3. 3. The heart : a regulated pump Cellular oxygenation, in particular for brain Long term control : hormones Short term control : autonomic nervous system Baroreceptor control loop: two antagonistic actions - sympathetic = accelerator (fast) - parasympathetic = inhibitor (slow) Control also acts on arteries and veins Sino atrial node
  4. 4. Cardiac electrical activity The heart contraction is driven by electric depolarization of myocyte cells inducted by cardiac fibers. Autonomous impulse generator Cardiac fibers Autonomic nervous system
  5. 5. Trans membrane voltage Depolarization Sodium ions Re polarization Potassium ions Restauration of ionic balance Cell membranes form electric dipoles
  6. 6. ECG Electric dipoles generated by cells membranes of the heart produces an electrical potential at the surface of the thorax. A set of electrodes, typically 3 to 10, are used to measure the electrical potential at different thorax locations. The electrocardiogram (ECG) records voltage evolution deduced from the measured potentials Cheap and non invasive
  7. 7. Typical ECG lead trace P wave Atrial depolarization QRS complex Ventricular depolarization T wave Ventricular repolarization
  8. 8. Applications of the ECG to cardiological diagnosis ● Arrhythmias detections ● Disorders in the activation sequences ● Increase in wall thickness or size of the atria and ventricles ● Myocardial ischemia (coronary atherosclerosis) and infarction ● ... Heart rate and ECG morphology analysis provides cheap diagnostic elements
  9. 9. The Cardiovascular Wave Analysis module Designed for – Long term ECG – Multi-leads records – Off line analysis Consists of five classes of tools – Data acquisition – Pretreatment – Event detection – Analysis – Visualization
  10. 10. Data acquisition Several file formats ● ISHNE Holter (Task Force standard) ● TMS32 ( signals recorded using TMS ADC system and PortiLab) ● WFDB (WaveForm DataBase used by Physionet) Can be read and converted into a Scilab structure: S=readTMS("ECG2.poly5",[25 27]); viewECG(S(:,1)) Or converted to Scilab specific format (ecgs) Easy for batch processing
  11. 11. Pretreatment ● ECG subsampling ● ECG FIR filtering ● Power line interference removal ● ECG detrending ● Finding and removing outliers viewECG([S(:,1) ECGSubstractPLI(S(:,1),50)])
  12. 12. Detections ● R peaks heart rate ● T wave ends Q-T segment ● All events S=extractPartFromEcgsFile(“P5J0.ecgs",... 100,3000); S1=ECGDetrend(S); S1=ECGSubstractPLI(S1,50); L=ECGDetections(SynthesisECG(S1)); ECGShowDetections(S(:,1),L)
  13. 13. Analysis tools Classical signal processing methods (heart rate spectral analysis) Multichannel non stationary signal analysis Baroreflex analysis (Arterial blood pressure effect on heart rate) Complex demodulation (Breathing rate effect on heart rate) Time frequency analysis Time domain characteristics Interactive tools HRVAS (Heart Rate Variability Analysis System), TimeFrequencyTool
  14. 14. The contribution of Scilab ● Signal processing and analysis ● Data file handling ● Graphics ● Graphical user interface ● Community ● Free multi-plateforms software
  15. 15. Acknowledgments - Detection algorithms : ● Quighua Zhang (INRIA) - Heart rate analysis algorithms: ● Alexandro Monti (INRIA) ● John T. Ramshur (U. Menphis) - Signal processing ● D.E. Lake, J.R. Moorman and C. Hanqing ● Wavelets :Christopher Torrence (Exelis), Gilbert. P. Compo (U. Colorado) ● George B. Moody, Cambridge ● Time Frequency toolbox: François Auger (CNRS), Holger Nahrstaedt (TU Berlin) - Data ● Physionet ● François Cottin (U. Paris Sud) ● Lisa Guigue ( INRIA) - Testing ● Claire Medigue (INRIA) ● Lisa Guigue (INRIA) - Atoms Module ( ● Dominique Callens (Scilab-Enterprises)
  16. 16. The end Thanks