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Electrocardiography is the process of producing an electrocardiogram (ECG or EKG [a]), a recording of the heart's electrical activity through repeated cardiac cycles. [4] It is an electrogram of the heart which is a graph of voltage versus time of the electrical activity of the heart [ 5 ] using electrodes placed on the skin.
Drawing of the ECG, with labels of intervals. Cardiac electrophysiology is a branch of cardiology and basic science focusing on the electrical activities of the heart.The term is usually used in clinical context, to describe studies of such phenomena by invasive (intracardiac) catheter recording of spontaneous activity as well as of cardiac responses to programmed electrical stimulation ...
His profound knowledge of the electrical phenomena underlying the electrocardiogram made him acutely aware of the many things apart from heart disease that may alter the records, and he often commented that the more a physician knows about electrocardiography the more conservative his interpretation of the records will be.
The right leg electrode acts to reduce interference, and can be placed anywhere without an effect on the ECG results. [6] Each lead measures the electric field created by the heart during the depolarization and repolarization of myocytes. The electric field can be represented as a vector that changes continuously and can be measured by ...
The hexaxial reference system is a diagram that is used to determine the heart's electrical axis in the frontal plane. The hexaxial reference system, better known as the Cabrera system, is a convention to present the extremity leads of the 12 lead electrocardiogram, [1] that provides an illustrative logical sequence that helps interpretation of the ECG, especially to determine the heart's ...
William Birnbaum with a Phonocardiogram System for use in Project Gemini, 1965. Awareness of the sounds made by the heart dates to ancient times. The idea of developing an instrument to record it may date back to Robert Hooke (1635–1703), who wrote: "There may also be a possibility of discovering the internal motions and actions of bodies - whether animal, vegetable, or mineral, by the sound ...
Willem Einthoven was born in Semarang on Java in the Dutch East Indies (now Indonesia), the son of Louise Marie Mathilde Caroline de Vogel and Jacob Einthoven. [2] His father, a doctor, died when Willem was a child.
The amplitude of ECG ranges from 0.3 to 2 mV for the QRS complex, which is used to determine the interbeat interval from which the frequency is derived. The typical requirements for the amplifiers to be used in ECG include: [1] Low internal noise (<2 mV) High Input Impedance (Z in > 10 MΩ) Bandwidth ranging from 0.16–250 Hz