“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 Biomedical Engineering Msc, FEUP, 2003 Contents

1. Context. Introduction to the Master’s thesis: “Model for educational simulation of the Neonatal ECG” “Trabalhos Práticos” – Final Presentation Biomedical Engineering Msc, FEUP, Educational Simulation

1. Context. Introduction to the Master’s thesis: “Model for educational simulation of the Neonatal ECG”. Educational Simulation “Trabalhos Práticos” – Final Presentation Biomedical Engineering Msc, FEUP, 2003 ( ). Eindhoven & Einthoven colaboration. Eindhoven & Einthoven colaboration

2. Introduction “Trabalhos Práticos” – Final Presentation Biomedical Engineering Msc, FEUP, 2003 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

3. Adult Electrophysiology. Electrical activity at the cellular level - The nerve resting membrane potential - The nerve action membrane potential - Propagation of the action potential “Trabalhos Práticos” – Final Presentation Biomedical Engineering Msc, FEUP, 2003

3. Adult Electrophysiology. Electrical activity at the cellular level - The nerve resting membrane potential - The nerve action membrane potential - Propagation of the action potential - Cardiac conduction system “Trabalhos Práticos” – Final Presentation Biomedical Engineering Msc, FEUP, 2003

3. Adult Electrophysiology. 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) “Trabalhos Práticos” – Final Presentation Biomedical Engineering Msc, FEUP, 2003

3. Adult Electrophysiology. 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 “Trabalhos Práticos” – Final Presentation Biomedical Engineering Msc, FEUP, lead Electrocardiogram

4. Reproduction of published simulation results. Dynamic model description “Trabalhos Práticos” – Final Presentation Biomedical Engineering Msc, FEUP, 2003 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. :

4. Reproduction of published simulation results. Dynamic model description “Trabalhos Práticos” – Final Presentation Biomedical Engineering Msc, FEUP, 2003 Baseline wander using the respiratory frequency f 2 Where: Differential Equations for the Dynamic Equations of motion:

4. Reproduction of published simulation results. Dynamic model description “Trabalhos Práticos” – Final Presentation Biomedical Engineering Msc, FEUP, 2003 Integration result - Equations of motion in the Discrete time domain: Used Technique: Euller method Where: T = 1/f s (Integration Step Size). Implementation considerations - Discretization

4. Reproduction of published simulation results. Dynamic model description. Implementation considerations - Discretization “Trabalhos Práticos” – Final Presentation Biomedical Engineering Msc, FEUP, 2003 Chosen Initial Values: x(1) = 1 y(1) = 0 z(1) = Choice of Initial Conditions

4. Reproduction of published simulation results. Dynamic model description. Implementation considerations - Discretization - Choice of Initial Conditions “Trabalhos Práticos” – Final Presentation Biomedical Engineering Msc, FEUP, 2003 Trajectory on the (x, y) plane with different values for T = 1/fs: - Choice of Integration Step Size

4. Reproduction of published simulation results. Dynamic model description. Implementation considerations - Discretization - Choice of Initial Conditions - Choice of Integration Step Size. Simulation Results “Trabalhos Práticos” – Final Presentation Biomedical Engineering Msc, FEUP, 2003 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. “Trabalhos Práticos” – Final Presentation Biomedical Engineering Msc, FEUP, 2003

An thorough understanding of Adult Electrophysiology forms the basis of Electrocardiography. Essential aspects were studied and summarized. 5. Conclusions & Future Perspectives “Trabalhos Práticos” – Final Presentation Biomedical Engineering Msc, FEUP, 2003

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 5. Conclusions & Future Perspectives “Trabalhos Práticos” – Final Presentation Biomedical Engineering Msc, FEUP, 2003

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. 5. Conclusions & Future Perspectives “Trabalhos Práticos” – Final Presentation Biomedical Engineering Msc, FEUP, 2003

6. References [1] Guyton AC: Textbook of medical physiology, 8th Edition, W.B. Saunders Company, Philadelphia, [2] Sheidt S: Basic Electrocardiography, 5 th Edition, Novartis, USA, 2000 [3] Campbell NA, Mitchell LG, Reece JB: Biology, concepts and connections, 3 rd Edition, Addison Wesley Longman, Inc., San Francisco, [4] Sá Couto CD: Model for educational simulation of the neonatal cardiovascular system, University of Porto College of Engineering MS(BME) thesis, Oct [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] [7] “Trabalhos Práticos” – Final Presentation Biomedical Engineering Msc, FEUP, 2003