•What is ECG?•How is it generated?•What type of informationdoes ECG tell?•How can we record it ?
What is ECG ? • Electrocardiogram (ECG)is the physical interpretation of the electrical behavior created by the heart muscles. ECG is the electrical activity of the heart
How is ECG generated? • Heart Cardiac cells are negatively charged. •Losing this negativity is called depolarization which is the fundamental electrical activity of the heart  .Depolarization propagates from cell to This wave is transmitted to the entire cell producing a wave heart producing a current This current can be detected using skin electrodes Skin Electrodes are put on the surface of the body The result is a periodic signal called ECG
P-wave : is produced by muscle Leftcontraction of atria. Right Atrium AtriumQRS-wave : marks the ending of atriacontraction and the beginning of ventricularcontractionT-wave : marks the ending of ventricularcontraction. Left Right ventricle ventricle
What type of information does ECG tell?  Any ECG gives two kinds of information First Secondthe duration of the electrical the amount of electrical wave crossing the heart activity through heart muscle decides whether enables to find the electrical whether the parts activity is normal of the heart are or slow or strong or irregular overworked. For example a narrow and high QRS-wave indicates a physically strong heart
How can we record it ? Special electrodes are put on the surface of the body as shown in the figureAfter amplifying the recorded signal , the obtained ECG signal is contaminatedwith different noises that must be cleared to get the best ECG .
Filtering Filter is an electronic device that passes and blocks certain frequencies. In most system, noise is suppressed. The most common types of noises that occur during the collection of ECG arePower line Interface Electrode Contact 60 HZ and its noise multiples less than 0.5Hz
Effect of Electrode contact noise • Movement of body and respiration• Lose of contact
Solution • Bandpass filter : Cascading a high pass and low pass filters the low and high frequency signal will be canceled. Input HPF LPF ECG• Once the clear ECG signal is obtained, further analysis is applied depending onthe application.
EXAMPLE •To calculate the heart beat, passing the filtered ECG through the differentiator will help to determine the maximum picks by detecting the slope. •R-R interval can then be calculated as shown in the diagram•The given formula will then calculate the Heart Beat.
Adaptive Filtering Algorithms for Noise Cancellation of ECG Signal with reference signal In this case two signals are required Primary signal Reference Input which which is the has two components common noisesClean ECG (S) + Noise signal ( n0 ) Estimated Noise signal (Y) The adaptive filters essentially minimizes the error between a primary input, which is the noisy ECG, and a reference input, which is either noise that is correlated in some way with the noise in the primary input or a signal that is correlated only with ECG in the primary input.
The adaptive noise canceling system of ECG signal Primary signal Adaptive Algorithm
Further AnalysisWavelet transforms are used in detectingirregularities in QRS section accurately.Wavelet Energy based Diagnostic Distortion(WEDD) for distortion measurement.Heart Rate Variability (HRV) to measureregulated emotional responding.
CONCLUSIONUsing the different techniques in processing the ECG,we hope to see accurate, robust ,and more advancedtools in cardiac care.We believe this will lead to put an end to heart diseasewhich is the number one killer.
References L. Wang, “The ECG Signal Processing by ADSP-21062 Digital Signal Processor”, Thesis submitted to the College of Engineering and Mineral Resources at West VirginiaUniversity,2005 . C. Saritha, V. Sukanya & Y. Narasimha Murthy, ECG Signal Analysis Using WaveletTransforms, February 2008 . http://www.adinstruments.com/, “Electrocardiogram and Heart Sounds”, AnIntroduction to the recording and analysis of electrocardiograms, and the sounds ofthe heart. Md. Zia Ur Rahman, R.A.Shaik & D V R. K. Reddy, “Noise Cancellation in ECG Signals using Computationally Simplified Adaptive Filtering Techniques: Application to Biotelemetry” , S. Z. Islam1, S. Z. Islam2, R. Jidin3 & M. A. M. Ali4, “Performance Study of AdaptiveFiltering Algorithms for Noise Cancellation of ECG Signal”,