Fourlead

Fourlead is a term used to describe a configuration in electrocardiography that employs four surface electrodes to monitor the heart’s electrical activity. It is commonly used for basic rhythm detection, heart rate monitoring, and simple arrhythmia screening, particularly in settings where a full 12-lead ECG is unavailable or impractical, such as bedside monitoring, emergency departments, ambulatory devices, or wearable sensors.

Configuration and operation: A four-lead setup attaches four electrodes to the patient, with the device determining signals by combining inputs from the electrodes and referencing a ground electrode. Depending on the device, the four inputs may be arranged to produce one or several derived leads. Some configurations provide a single-lead tracing suitable for rapid rhythm assessment, while others yield multiple derived leads that offer limited comparative information.

Applications and limitations: Four-lead systems are valued for simplicity, speed, and portability. They enable continuous bedside monitoring, early detection of abnormal heart rhythms, and basic screening for ischemia in triage or interim settings. However, they offer less information than a full 12-lead ECG, with reduced capacity to localize ischemia, identify detailed infarction patterns, or assess ventricular axis. Accurate interpretation typically requires trained personnel, and results should be supplemented with a 12-lead ECG whenever possible.

Variations and devices: Four-lead configurations appear in a range of devices, from inpatient monitors to wearable or telemedicine tools. The term may refer to specific four-electrode arrays designed for four-lead operation or to the subset of data derived from larger multi-lead systems.

See also: Electrocardiography, Lead (electrophysiology), 12-lead ECG, Cardiac monitoring.