12 Lead ECG
The 12-lead ECG is usually performed over a few minutes whilst the patient is laying down. By monitoring the conduction waveforms of the heart from a variety of viewpoints, it is possible to assess any resting abnormality likely to indicate heart disease.
The ECG may provide information on excess thickening of the heart wall, current or previous heart attacks, conduction defects, and abnormal rhythms. It may also be used to diagnose electrolyte imbalance and assess medication therapy.
It is less useful for occasional arrhythmia as the chances of the patient having an event during a short test is often very low. It is also of little use for coronary artery disease as the patient is at rest and therefore unlikely to suffer an ischaemic episode.