- ECG (electrocardiography)
- When and how is the ECG used?
In order for the heart muscle to pump as regularly as possible year in and year out, pulses are sent out by a pacemaker. These electrical activities can be recorded with electrocardiography. Her pattern provides information about heart function, rhythm and expired infarcts. After 70 years, the heart has contracted about 3 billion times and relaxed again to pump around 7,000 liters of blood through the body every day. In order to achieve this performance, a stimulus is generated by the so-called sinus node 60- to 70-times per minute in the healthy at rest, which spreads as electrical current through certain pathways to the heart muscle and this animated to pump. The sinus node is a network of specialized heart muscle cells in the right atrium of the heart and controls the heartbeat frequency, thus serving as a natural pacemaker. The heart constantly motivates itself to work.
The ECG - how does it work?
Since the human body conducts current, this excitation spread in the heart can be recorded in a graph. For this purpose, a plurality of metal plates are attached as electrodes at certain intervals on the body surface and derived the intermediate voltage fluctuations (electrical potentials). They are amplified in the ECG device and displayed or printed on the monitor. Since the electrical impulse changes direction during its course, the curve (electrocardiogram) also varies depending on the time of the action. The entire resulting process is repeated at every heartbeat. Tissue changes as z. B. after a heart attack, lead to the diversion of the currents and thus to typical deviations.
What for the layman at best looks like line drawings of mountains and valleys, gives the expert valuable information about the heart action. In addition to the rhythm, ie the frequency and regularity of the voltage changes, their size, direction and duration are also evaluated. Thus, disorders of arousal formation, spreading and regressions in the conduction system and in the heart muscle can be determined and the position of the heart in the chest determined.