EKG Dictionary
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Recording & method

12-lead ECG

Also called12-lead EKG · twelve-lead ECG · standard ECG · resting ECG · standard 12-lead ECG

Definition

The standard diagnostic recording that shows the heart's electrical activity in 12 leads: 6 limb leads (I, II, III, aVR, aVL, aVF) that view the heart in the frontal (vertical) plane and 6 chest (precordial) leads (V1 through V6) that view it in the horizontal plane, all derived from 10 electrodes (4 on the limbs, 6 on the chest). It is used to diagnose arrhythmias, acute coronary syndromes and myocardial infarction, intraventricular conduction disturbances and ventricular hypertrophy. Standard recording is at 25 mm/s paper speed with a gain of 10 mm/mV.

Sources

  1. Kligfield P, Gettes LS, Bailey JJ, et al. Recommendations for the standardization and interpretation of the electrocardiogram: part I: the electrocardiogram and its technology. Circulation. 2007;115(10):1306-1324. doi.org/10.1161/CIRCULATIONAHA.106.180200
  2. Meek S, Morris F. ABC of clinical electrocardiography. Introduction. I: Leads, rate, rhythm, and cardiac axis. BMJ. 2002;324(7334):415-418. doi.org/10.1136/bmj.324.7334.415

Last reviewed 2 October 2026. Every definition in the EKG Dictionary cites the guideline, consensus statement or original paper it comes from.

More in Recording & method

Artifact Augmented limb leads Dextrocardia ECG calibration Einthoven triangle Lead II Limb leads Precordial (chest) leads Rhythm strip Right-sided and posterior leads

See it on real ECGs

EKGLab's free library holds more than 21,000 real 12-lead recordings with expert reads, and long arrhythmia recordings with every beat labelled.

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