Limblead

Limblead is not a standard term in medical literature. It is commonly a misspelling or informal shorthand for limb lead, a component of electrocardiography. In some cases, Limblead may refer to a brand or fictional device; this article focuses on the general concept of limb leads as used in ECG.

Limb leads are electrodes placed on the limbs to record the heart's electrical activity in the frontal plane. The standard configuration includes three limb leads I, II, and III, which form Einthoven's triangle, and three augmented limb leads aVR, aVL, and aVF, which provide additional perspectives.

Placement: Right arm, left arm, and left leg are used for positive electrodes in the standard limb leads; a ground electrode is typically placed on the right leg. For some patients, leg electrodes may be placed on the abdomen or torso to reduce motion and artifact.

Function: Limb leads are recorded together with precordial leads (V1-V6) to create a 12-lead ECG. They help determine the direction and magnitude of the heart's electrical axis and support diagnosis of ischemia, infarction, hypertrophy, conduction abnormalities, and arrhythmias. They do not provide detailed information about chest wall conduction, which is provided by precordial leads.

History and terminology: The concept originates from Einthoven's pioneering work in electrocardiography in the early 20th century. The term limb leads is standard; limblead is rarely used outside informal contexts, and if encountered, often indicates a typographical error.

See also: Electrocardiography, Electrocardiogram, Limb leads, Einthoven's triangle.