Ecg ppt


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Ecg ppt

  1. 1. Page 1
  2. 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. 5. ECG is detected by Einthovens triangle method Page 5
  6. 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. 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. 9. HEART WAVES QRS P wave- SA wave- cumulati node Time vegenetrated, 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. 10. T wave- repolarization of ventricleAmplitude- Amplitude- 0.01mV 0.3mV U wave- after Time duration- potential in 120-160ms ventricle Page 10
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  12. 12. DETECTION OF QRS EVENTUsing PAN tompkins Recognises QRS on the bases of algorithm slope, width, amplitude Page 12
  13. 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. 15. High pass It has a DCfilter gain of 32 Page 15
  16. 16. DifferentiationIn differentiation, technique for finding slopes thatdistinguish QRS wave from other ECG wave. Page 16
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  18. 18. Squaring Makes all dataPoint-by-point positive andsquaring of the accentuates highersignal samples frequencies (QRS) Page 18
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  20. 20. Adaptive thresholdingAdaptive thresholding It updates the peak is done on the basis level & noise levelof BPF waveforms & and determine if it is a moving-window QRS event or not integral Page 20
  21. 21. Artifacts in ECG High frequency noise Wandering base line Power line interference Page 21
  22. 22. High frequency noiseMaybe formed by instrumentation amplifier, recording device orelectrodes may pickup ambient EM signals by cables Page 22
  23. 23. Power line interface Odd harmonics areMaybe formed if ECG generated which would besignal is not properly represented as spikes on sinusoidal ECG waveform Page 23
  24. 24. Wandering Base line Isoelectric line is not fixed, noise in the signal Patient needs to be Also known as motionstatic, 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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