CHAPTER 2
2.1 ELECTROCARDIOGRAM
The ECG Signal is a graphical representation of the electromechanical activity of system. The various propagation action potentials within the heart produce a current flow, which generates an electrical field that can be detected, in significantly attenuated form, at the body surface, via a differential voltage measurement system. The resulting measurement, when taken with electrodes in standardized locations, is known as the electrocardiogram. The ECG signal is typically in the range of ±2 mv and requires a recording bandwidth of 0.05 to 150 Hz. Under the normal condition, ECG tracing have a very predictable direction, duration and amplitude. Because of this, the various components of the ECG tracing can be …show more content…
Even if removed from the heart and placed in culture, the cells have the self-excitation property. The electrical potentials for contraction are caused by a group of specialized cells in the heart which control the heartbeat. These cells produce electrical impulses which spread across the heart causing it to contract. The main pacemaker of heart, the senatorial node, initiates the heart beat by generating an electrical impulse which travels to the left and right atria, causing them to contract. Following the start of atrial depolarization, the impulse quickly arrives at the atrioventricular node which is responsible for the contraction of ventricle. The SA node creates the electrical impulse which causes the heart to beat, but the Autonomic Nervous System controls the heart rate and the strength of heart contractions. The ANS consists of two parts, the Sympathetic Nervous System and the Parasympathetic Nervous System. The Sympathetic nerves increase the heart rate and the contraction force, while the Parasympathetic nerves act in the reverse manner. A small portion of this electrical potential flows to the body surface. By applying electrodes on the skin at the selected points, the electrical potential generated by this current can be recorded as an ECG signal. …show more content…
In the India, the electricity supply in 60 Hz and the other country like as Europe in many places use 50 Hz alternative current electricity. Power line interference occurs through two mechanisms: capacitive and inductive coupling. Capacitive coupling refers to the transfer of energy between two circuits by means of a coupling capacitance present between the two circuits. The value of the coupling capacitance decreases with increasing separation of the circuits. Inductive coupling on the other hand is caused by mutual inductance between two conductors. When current flows through wires it produces a magnetic flux, which can induce a current in adjacent circuits. The geometry of the conductors as well as the separation between them determines the value of the mutual inductance, and hence the degree of the inductive coupling. Typically, capacitive coupling is responsible for high frequency noise while inductive coupling introduces low frequency noise. For this reason inductive coupling is the dominant mechanism of power line interference in electro cardiology. To limit the amount of power line interference, electrodes should be applied properly, that there are no loose wires, and all components have adequate shielding.
2.1 ELECTROCARDIOGRAM
The ECG Signal is a graphical representation of the electromechanical activity of system. The various propagation action potentials within the heart produce a current flow, which generates an electrical field that can be detected, in significantly attenuated form, at the body surface, via a differential voltage measurement system. The resulting measurement, when taken with electrodes in standardized locations, is known as the electrocardiogram. The ECG signal is typically in the range of ±2 mv and requires a recording bandwidth of 0.05 to 150 Hz. Under the normal condition, ECG tracing have a very predictable direction, duration and amplitude. Because of this, the various components of the ECG tracing can be …show more content…
Even if removed from the heart and placed in culture, the cells have the self-excitation property. The electrical potentials for contraction are caused by a group of specialized cells in the heart which control the heartbeat. These cells produce electrical impulses which spread across the heart causing it to contract. The main pacemaker of heart, the senatorial node, initiates the heart beat by generating an electrical impulse which travels to the left and right atria, causing them to contract. Following the start of atrial depolarization, the impulse quickly arrives at the atrioventricular node which is responsible for the contraction of ventricle. The SA node creates the electrical impulse which causes the heart to beat, but the Autonomic Nervous System controls the heart rate and the strength of heart contractions. The ANS consists of two parts, the Sympathetic Nervous System and the Parasympathetic Nervous System. The Sympathetic nerves increase the heart rate and the contraction force, while the Parasympathetic nerves act in the reverse manner. A small portion of this electrical potential flows to the body surface. By applying electrodes on the skin at the selected points, the electrical potential generated by this current can be recorded as an ECG signal. …show more content…
In the India, the electricity supply in 60 Hz and the other country like as Europe in many places use 50 Hz alternative current electricity. Power line interference occurs through two mechanisms: capacitive and inductive coupling. Capacitive coupling refers to the transfer of energy between two circuits by means of a coupling capacitance present between the two circuits. The value of the coupling capacitance decreases with increasing separation of the circuits. Inductive coupling on the other hand is caused by mutual inductance between two conductors. When current flows through wires it produces a magnetic flux, which can induce a current in adjacent circuits. The geometry of the conductors as well as the separation between them determines the value of the mutual inductance, and hence the degree of the inductive coupling. Typically, capacitive coupling is responsible for high frequency noise while inductive coupling introduces low frequency noise. For this reason inductive coupling is the dominant mechanism of power line interference in electro cardiology. To limit the amount of power line interference, electrodes should be applied properly, that there are no loose wires, and all components have adequate shielding.