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Electrocardiogram (ECG) is a non-stationary non-linear aperiodic time signal (Chatterjee et al., 2020). ECG signal measures the muscular and electrical function of the heart. The ECG signal will vary with respect to time by the cause of contraction and relaxation of the artery and ventricle of the heart. ECG measurement is done by attaching the electrodes to the patient's body. In recent years, 10 electrodes are used and placed on the limbs and chest that capture heart rate, electrical activity and rhythm information. ECG contains both physiological and pathological information, both of which are important in the diagnosis of cardiac problems. In clinical applications, ECG monitoring will be crucial. However, ECG contains a variety of noises that muddle the morphological properties of the ECG, resulting in a misleading diagnosis and improper treatment of the patients. Empirical Mode Decomposition, Wavelet transform, and adaptive filtering are a few methods for denoising the ECG signal. The most common method of denoising is adaptive filtering. The wavelet transform is a modern technique that employs various thresholding methods.
Figure.1 shows the ECG signal with a typical time interval. The ECG signal contains 3 different components. They are
- 1.
P wave
- 2.
QRS complex
- 3.
T wave.
Also, it contains the components of the segments
- 1.
PR-segment
- 2.
ST-segment,
- 3.
PR interval,
- 4.
ST interval,
- 5.
RR interval and so on.
ECG signal can be used in many medical fields’ applications such as seizure detection, cardio respiratory monitoring, and monitoring. These signals are also employed in electrocardiographic rhythm analysis, biometrics authentication, cardiac ischemia research and heart-rate variability analysis with a smart electrocardiography patch (Islam et al., 2012), (Liang et al., 2005), (Eberhart et al., 1995), (Chinchkhede et al., 2011), (Li et al., 2008), (Omran et al., 2006), (Blackwell et al., 2006). Many signal processing (Nagajyothi et al., 2017) methods are present to reduce the noise from the ECG signals. Baseline wander, EMG noise, electrode motion artifacts and power line interference are the four main artifacts present in the ECG.