Heart is a vital organ which pumps blood to all the parts. The heart expands and contracts to pump the blood. This contraction and expansion of heart is what we hear as a heart beat. Every time the heart beats, small electrical impulses are discharged. These electrical impulses specify the heart's condition. These electrical impulses can be measured through a process called electrocardiography.
The electrocardiography (electrocardiogram) is better known as an ECG, but is also called EKG. Electrocardiography often used for diagnosing heart disorders which include coronary heart disease, pericarditis or inflammation of the membrane around the heart, cardiomyopathy or heart muscle disease, arrhythmia and coronary thrombosis. The electrocardiography is a painless and quick procedure.
In 1893, Willem Einthoven introduced the term electrocardiogram. In 1924, Einthoven received the Nobel Prize for his life's work in developing the electrocardiography,described the electrocardiographic features and its relation to cardiovascular disorders.
In electrocardiography several thin wires (wires with small metal contacts called electrodes) are attached to the body at different points to collect the electrical impulses. Generally electrodes are connected to the chest, wrist and ankles. When attached, these electrodes are called leads, three to 12 leads may be employed for the procedure. The wires are fed to a machine that measures them and produces a readout. The electrical impulses in the heart are recorded and amplified by the machine. Before the leads are attached, the skin is cleaned to obtain good electrical contact at the electrode positions and, occasionally, shaving the chest may be necessary.
An electrocardiography represents electrical impulses as waves that are known as the P, Q, R, S, and T waves which give each part of the Electrocardiography an alphabetical designation. As the heart beat begins with an impulse, the impulse will first activate the upper chambers of the heart or atria and produce the P wave. Then the lower chambers of the heart or ventricles are stimulated producing the Q, R and S waves. As the electrical impulses spreads back over the ventricles in the opposite direction it will produce the T waves. Using this technique doctors can determine abnoemalities in the functioning of heart.