Ecg ppt
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This document discusses the electrocardiogram (ECG) and the electrical activity of the heart. It provides information on how ECG is used to measure heart rate and detect any heart damage. The basics of heart anatomy and function are described, including the four chambers and pacemaking nodes. The key waves of the ECG are defined, such as the P, QRS, and T waves. Methods for detecting QRS complexes are outlined, including filtering, differentiation, and thresholding. Potential artifacts in ECG signals are also reviewed, such as noise, baseline wandering, and powerline interference.
Ecg ppt
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- 2. ECG • Interpretation of the electrical activity of the heart over a period of time • Electrical manifestation of the activity of the heart. Recorded with surface electrodes on the limbs or chest. • ECG is used to measure the rate and regularity of heartbeats, the presence of any damage to the heart. Page 2
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- 5. ECG is detected by Einthoven's triangle method Page 5
- 6. THE HEART • It is a 4 chambered muscular organ consist of 2 atriums and 2 ventricles. • It function in a regular fashion to pump blood thought the body. • Average heart rate of a human being is 72beats/min Page 6
- 7. • SA node- sinoartial node- acts like a function generator, called pacemaker of heart • AV node- artioventricular node- acts like a delay device Page 7
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- 9. HEART WAVES QRS P wave- SA wave- cumulati node Time ve genetrated, du Amplitude- 0.1 Amplitude- Time duration- duration- 60-8 repolarization e to to 0.2 mV 1mV 80ms 0ms of atria & contraction of depolarization atria. of ventricle. Page 9
- 10. T wave- repolarization of ventricle Amplitude- Amplitude- 0.01mV 0.3mV U wave- after Time duration- potential in 120-160ms ventricle Page 10
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- 12. DETECTION OF QRS EVENT Using PAN tompkins Recognises QRS on the bases of algorithm slope, width, amplitude Page 12
- 13. Band-pass filter In order to attenuate noise Attenuates low the signal is frequency of P & passed through a T waves, baseline bandpass filter, drift, high composed of a frequencies of high pass filter EMG and power and a low pass line interference filter. Page 13
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- 15. High pass It has a DC filter gain of 32 Page 15
- 16. Differentiation In differentiation, technique for finding slopes that distinguish QRS wave from other ECG wave. Page 16
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- 18. Squaring Makes all data Point-by-point positive and squaring of the accentuates higher signal samples frequencies (QRS) Page 18
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- 20. Adaptive thresholding Adaptive thresholding It updates the peak is done on the basis level & noise level of BPF waveforms & and determine if it is a moving-window QRS event or not integral Page 20
- 21. Artifacts in ECG High frequency noise Wandering base line Power line interference Page 21
- 22. High frequency noise Maybe formed by instrumentation amplifier, recording device or electrodes may pickup ambient EM signals by cables Page 22
- 23. Power line interface Odd harmonics are Maybe formed if ECG generated which would be signal is not properly represented as spikes on sinusoidal ECG waveform Page 23
- 24. Wandering Base line Isoelectric line is not fixed, noise in the signal Patient needs to be Also known as motion static, electrodes should artifact be clean Maybe arise due to patient movement, movement of external source, patient body’s (inside) movement. Page 24
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