An electrocardiogram or ECG is a test widely used to assess and evaluate the status of the heart’s electrical conduction system. ECGs are done with a device called an electrocardiograph. An ECG is a graphical presentation of the electrical activity of the heart muscles and is measured by an ECG machine. The curvy lines in an ECG report represent the recordings of an ECG machine that read heart beats, display them on a monitor and can also print them out on paper. These readings are the tools for diagnosing abnormalities in the heart.
PC based ECG machines generally consist of a Digital ECG device with a cable that splits into individual wires called leads. Electrodes are attached to the end of each lead and are placed on a patient’s chest to record the heart’s electrical activity. The results of the ECG can be viewed directly on the PCs screen. They can also be transmitted through a wireless Soma Technology network to a computer for viewing at a different location. It is capable of storing several ECG readings, and displaying up to four separate results at the same time for comparison. The PC or server can be connected to a printer to produce a hard copy of the tracings. Advanced clinics now frequently use Wireless ECG. A physician who works in more than one clinic would prefer a Portable ECG or Mobile ECG.
ECG is one of the most important and readily available tools in cardiac diagnosis. It measures the rate and promptness of heartbeats as well as the size and position of the chambers, the presence of any damage to the heart, and the effects of devices used to regulate the heart, like a pacemaker and medications.
To perform an electrocardiogram, 10 ECG leads (electrodes) are attached to each limb and to 6 pre-defined points on the chest, while the patient lies flat on a bed. The skin is coated with a small amount of water or gel that permits the electrical signals of the heart to be more easily transmitted to the leads. This painless test continues for about 5 minutes and the results can be stored to and reviewed on a PC and to be printed if so desired. A quality electrocardiogram should be a 12 Lead ECG.
During ECG tracing, it is essential to be relaxed and relatively warm, because any motion, including muscle tremors such as shivering, will change the recording. Other factors affecting ECG results are movement or faulty position of the leads, disproportion of electrolytes in blood (such as too much or too little calcium, potassium, magnesium or sodium), and low body temperature.