Ecg Lab Report

CHAPTER 1. INTRODUCTION

The greatest progress to date in the use of computers for the clinical analysis of physiological data has occurred in the field of cardiology. There are several reasons for this; first of all, electrocardiogram (ECG) potentials are relatively easy to measure; secondly, the ECG is an extremely useful indicator for both screening and diagnosis. In addition, certain abnormalities of the ECG are quite well defined and can be readily identified. The ECG signal provides the following information of a human heart [1]: Impulse origin and propagation Drug effects on the heart Heart position and its relative chamber size Changes in electrolyte concentrations Extent and location of myocardial ischemia Heart rhythm

The heart is a hollow muscle that is about the size of a fist. In one minute, it pumps about five liters (roughly five quarts) of blood through the body, it is made up of four chambers as shown in Figure 2 .1 Right Atrium (RA), Left Atrium (LA), Right Ventricle (RV), Left Ventricle (LV). An ECG is a diagnosis tool that reported the electrical activity of heart recorded by skin electrode. The morphology and heart rate reflects the cardiac health of human heart beat [16]. It is a noninvasive technique that means this signal is measured on the surface of human body which is used in identification of the heart diseases [17, 18]. Any disorder of heart rate or rhythm, or change in the morphological pattern, is an indication of cardiac arrhythmia which could be detected by analysis of the recorded ECG waveform. The amplitude and duration of the PQRS-T wave contains useful information about the nature of disease afflicting the heart. The electrical wave is due to depolarization and repolarization of Na+ and K ions in the blood [17]. Electrocardiography is considered to be one of the most powerful diagnostic tools in medicine that is routinely used for the assessment of the functionality of the heart. An ECG is the conventional method for noninvasive interpretation of the electrical activity of the heart in real-time. The electrical cardiac signals are recorded by an external device by attaching electrodes to the outer surface of the skin of the patient’s thorax. These currents stimulate the cardiac muscle and cause the contractions and relaxations of the heart. The electrical signals travel through the electrodes to the ECG device which records them as characteristic waves. Different waves reflect the activity of different areas of the heart which generate the respective flowing electrical currents. Figure 2.2