ECG Monitors

Electrocardiography (ECG) is a non-invasive method of measuring the electrical activity of the heart over time, using electrodes that are attached to the surface of the skin. Twelve-lead ECGs are used to record cardiac electrical activity at a specific point in time and are generally printed to create a permanent record. ECGs that use 3 or 5 leads are commonly used for continuous recording of cardiac activity in ambulances, during surgery and/or when patients are receiving anesthesia, and to monitor critically ill patients.

Most ECG monitors offer a monitoring mode and a diagnostic mode. Monitor mode features a narrow passband of between 0.5 or 1 Hz and 40 Hz, which limits artifact for routine monitoring. In diagnostic mode, a wider passband of 0.5 up to 100 or 150 Hz is recorded, enabling accurate ST segments to be recorded.

Diagnostic ECGs may be done while the patient is resting or ambulatory, or as part of a stress test. Ambulatory ECGs are often referred to as Holter monitors.

Faster detection and more accurate diagnosis of cardiac events enable faster intervention in cases of chest pain or arrhythmia, and result in better outcomes and cardiac event treatments. Many ECG monitors for resting or cardiac stress test ECGs include advanced analysis tools and can be customized to match treatment protocols.

Monitors for ambulatory ECGs are generally worn by patients for a 24 hour period. As such, they must be sturdy, lightweight, compact and accurate. Features such as the ability to detect faulty electrode contacts or low batteries lower the risk of corrupted or truncated recordings and minimize the likelihood of having to repeat a recording. Ambulatory ECG monitors may include analysis engines or be combined with telemetry transmitters that transmit Holter results to cardiac monitoring units in real time.

ECG monitors range from small portable Holter monitors and compact, simple systems that are suitable for clinics, to sophisticated and highly sensitive monitors for use in emergency rooms and ICUs. Major producers of monitors include GE Healthcare, Schiller, Welch Allyn, Omron Healthcare, Newtech Medical and many more.