ECG stands for Electrocardiogram. The ECG is a recording of electrical activity of the heart. It is performed in the doctors office or in hospital.
Small electrodes (stickers) are attached to the arms, legs and chest. Wires with metal clips are attached to the metal part of the electrodes and the wires transmit the electrical signal from the heart to the ECG machine. The machine amplifies the electrical signal and records the signal on ECG paper in the form of voltage. The process is very quick and simple. An ECG relies on the patient's ability to remain still for approximately two minutes. The ECG machine only monitors electrical impulses and does not deliver an electrical stimulus. There is an extremely low risk of an allergic reaction to the electrodes. This risk is further reduced by the small amount of time the electrodes are in contact with the skin.
Reasons for the Test
There are a variety of reasons why an ECG may be required. The main reasons are:
- Arrhythmia irregularity in the heart's normal rhythm
- Chest pain non-specific, muscular or cardiac related
- Suspected Heart Disease to evaluate any heart chamber enlargement and or conduction abnormalities.
Other reasons may include but are not limited to;
- Infections various tissues of the heart can get attacked by bacteria and viruses
- Cardiomyopathy changes in the heart muscle that significantly affects the function of the heart
- Medication some medications may affect the heart and cause ECG changes. Often a baseline ECG prior to commencing medication will be requested
- Noncardiac reasons an ECG may be performed in situations where cardiac disease may develop as a consequence of another medical condition, for example anorexia nervosa or electrolyte imbalance.
What information will the ECG provide about my heart?
The ECG provides important information on the heart rhythm and how the electrical signals spread through the heart. The ECG tells us how fast and how regular the heart is beating. Any rhythm abnormalities occurring at the time of the ECG will be detected. Depending on the arrhythmia, a treatment may be recommended. We can also see if the conducting system of the heart is functioning properly. There are several conductive pathways in the heart and if a pathway is damaged, the signal will not be transmitted properly. The ECG enables doctors to locate the conduction defect and administer appropriate treatment. The ECG can also indicate, to some extent, the dimensions of the heart. If a chamber of the heart has extra muscle, such as in certain types of cardiomyopathy, indicators of the extra muscle mass may be seen on the ECG. Electrolyte imbalance is a condition which may cause arrhythmias. The imbalance produces particular features on the ECG and, once recognised, the imbalance can be quickly corrected. An ECG can also tell us if the heart is receiving enough oxygen and if part of the heart muscle has been damaged due to blockages in the coronary arteries. If a patient has a pacemaker implanted, an ECG may be useful to check that the device is functioning properly. We are interested in seeing if the signal is being sent from the pacemaker to the heart and if the heart is responding to the pacing signal.