lead1

An electrocardiographic cable with connections within the electronics of the machine designated for an electrode placed at a particular point on the body surface.

- ABC leads the leads for recording one kind of vectorcardiogram utilizing the Arrighi triangle; supplanted by XYZ leads.

- augmented l. electrocardiogram recorded between one limb and two other limbs. The augmented leads are designated aVF, aVL, and aVR for recordings made between the foot (left), left arm, and right arm, respectively, and the other two limbs.

- bipolar l. a record obtained with two electrodes placed on different regions of the body, each electrode contributing significantly to the record; e.g., a standard limb l..

- CB l. a bipolar chest l. with the negative electrode placed upon the subject's back.

- CF l. a bipolar chest l. with the negative electrode placed on the subject's left leg.

- chest leads those in which the exploring electrode is on the chest overlying the heart or its vicinity. SYN: precordial leads, semidirect leads.

- CL l. a bipolar chest l. with the negative electrode placed on the subject's left arm.

- CR l. a bipolar chest l. with the negative electrode placed on the subject's right arm.

- direct l. in electrocardiography, a unipolar l. recorded with the exploring electrode placed directly on the surface of the exposed heart.

- esophageal l. an electrocardiographic l. passed down the throat into the esophagus to record the electrocardiogram at various levels of the esophagus; especially useful for certain types of arrhythmias. Similarly, a transducer for echocardiography can be passed into the esophagus.

- indirect l. SYN: standard limb l..

- intracardiac l. the record obtained when the exploring electrode is placed within one of the heart's chambers, usually by means of cardiac catheterization.

- limb l. one of the three standard leads (leads I, II, III) or one of the unipolar limb leads (aVR, aVL, aVF).

- precordial leads SYN: chest leads.

- semidirect leads SYN: chest leads.

- standard limb l. one of the three original bipolar limb leads of the clinical electrocardiogram, designated I, II, and III: l. I records the potential difference between the right and left arms; l. II the difference between right arm and the leg electrode; and l. III the difference between left arm and the leg electrode. SYN: indirect l..

- unipolar leads those in which the exploring electrode is on the chest in the vicinity of the heart or on one of the limbs, while the other or indifferent electrode is the central terminal.

- V l. a unipolar l. with the central terminal as the indifferent electrode; V is the symbol for unipolar (Latin “U”).