“model for educational simulation of the neonatal ecg” trabalhos práticos - final presentation

“Model for Educational Simulation of the Neonatal ECG”

Trabalhos Práticos - Final Presentation

Author: J. Rodolfo Pinto

Supervisor: Prof. Willem Van Meurs

Biomedical Engineering Msc, FEUP, 2003

1. Context

2. Introduction

3. Adult Electrophysiology

4. Reproduction of published Simulation Model

5. Conclusion & Future perspectives

6. References

“Trabalhos Práticos” – Final Presentation


Contents

1. Context

. Introduction to the Master’s thesis: “Model for educational simulation of the

Neonatal ECG”



. Educational Simulation

1. Context

. Introduction to the Master’s thesis: “Model for educational simulation of the Neonatal ECG”

. Educational Simulation



(1869 - 1927). Eindhoven & Einthoven

colaboration

. Eindhoven & Einthoven

colaboration

2. Introduction



• Objectives of this mini-project:

• It focuses on the following elements:

- Adult Electrophysiology and Neonatal Cardiovascular Physiology

- Literature search of existing models and target data

- Simulation model reproduction and evaluation

- To introduce and become familiar with …… some of the physiological subject matter

… modelling and simulation techniques


. Electrical activity at the cellular level

- The nerve resting membrane potential

- The nerve action membrane potential

- Propagation of the action potential








- Cardiac conduction system









. Electrocardiography

- The basic ECG. P wave, QRS complex, T wave

. Time intervals (ST segment, isoelectric region)

. Amplitudes (R peak amplitude, P detection)









. Electrocardiography

- The basic ECG



- 12-lead Electrocardiogram

4. Reproduction of published simulation results

. Dynamic model description



Quasi-periodicity of the ECG is explored to generate a trajectory in a 3-D state-space with coordinates (x,y,z).

The trajectory is around a limit cycle of unit radius in the (x,y) plane

Model proposed by McSharry et al.:





yxx

xyy

0

,,,,

2 2

2

zzeazTSRQPi

bii

i

i

221 yx

2modii

xyatg ,2

t

2

tfAtz 20 2sin

Baseline wander using the respiratory frequency f2

Where:

Differential Equations for the Dynamic Equations of motion:





2 21 1x n x n T x n y n x n y n

2 21 1y n y n T x n y n y n x n

0

2

2mod

,,,,

2

2

2mod1 znzeaTnznz i

i

b

TSRQPiii

Integration result - Equations of motion in the Discrete time domain:

Used Technique: Euller method

Where: T = 1/fs (Integration Step Size)

. Implementation considerations

- Discretization




- Discretization



Chosen Initial Values:

x(1) = 1

y(1) = 0

z(1) = 1.2

- Choice of Initial Conditions




- Discretization




Trajectory on the (x, y) plane

with different values for T = 1/fs:

- Choice of Integration Step Size




- Discretization


- Choice of Integration Step Size

. Simulation Results



Author results Vs Reproduction best results:

5. Conclusions & Future Perspectives

• The work in this mini-project provided background information for future phases in the planned masters work at the University of Technology, Eindhoven, The Netherlands, and introduced some of the concepts that will be used for generating neonatal ECGs.



• An thorough understanding of Adult Electrophysiology forms the basis of Electrocardiography. Essential aspects were studied and summarized.




• The ECG simulation results reproduced on this report were positive but require further adjustments. The literature search and analysis will be extended to other models. Depending on the specific neonatal requirements, some of those models may be applied directly, or adapted or redesigned to produce realistic synthetic ECGs




The next step(s) ...

• Specific Neonatal Electrophysiology will be studied next. The Neonatal ECG has many specific issues that will be studied and applied on simulation together with neonatology experts at the Maxima Medical Center in Veldhoven, The Netherlands.




6. References

[1] Guyton AC: Textbook of medical physiology, 8th Edition, W.B. Saunders Company, Philadelphia, 1991.

[2] Sheidt S: Basic Electrocardiography, 5th Edition, Novartis, USA, 2000

[3] Campbell NA, Mitchell LG, Reece JB: Biology, concepts and connections, 3 rd Edition, Addison Wesley Longman, Inc., San Francisco, 1999.

[4] Sá Couto CD: Model for educational simulation of the neonatal cardiovascular system, University of Porto College of Engineering MS(BME) thesis, Oct. 2002.

[5] McSharry PE, Clifford GD, Tarassenko L, Smith LA: A Dynamical Model for Generating Synthetic Electrocardiogram Signals, IEEE Transactions on Biomedical Engineering, Vol. 50, No 3, March 2003

[6] http://faculty.washington.edu/chudler/ap.html

[7] http://www.blackwellscience.com/matthews/actionp.html



“model for educational simulation of the neonatal ecg” trabalhos práticos - final presentation

Documents

simulation techniques3

cellular level

electrical activity

y plane model

educational simulation1

p wave

masters thesis

coordinates x