What is an electrocardiogram and what are its visible components when one is printed out?
An electrocardiogram is a reflection of the electrical activity of the heart. All of the components of an electrocardiogram vary for the hearts of different species of animals and the most information is known about the human heart. The changes in the duration of the plateau of the action potential and the rates of depolarization and repolarization of the heart are recorded as an electrocardiogram. The duration of the action potential in animals is directly related to the maximum frequency of an animal s heartbeat. Atrial cells have shorter action potentials than ventricular cells. In smaller mammals, the duration of the ventricular action potential is shorter and the heart rates are higher. All of these electrically-generated controls of the heart can be recorded in an electrocardiogram. Electrodes are placed on a patient so that the view that appears on the screen is an electric view across the heart. Each of the peaks on an electrocardiogram is given one or more initials. The first
