The ECG Leads

The electrocardiogram (ECG) traces the variation in voltage produced by the heart muscle during depolarization and repolarization. The standard ECG records depolarization and repolarization along designated paths called lead systems.

A lead or lead system is an electrical picture of a heart’s surface. Each lead traces the electrical activity between two points. Each lead traces the electrical activity between two points. Each lead traces the electrical activity between two points called electrodes. Electrodes of opposite polarity make up a bipolar lead. One positive electrode and a reference point make up a unipolar lead. Six limb leads (three bipolar and three unipolar) and six precordial leads make up the standard 12-lead ECG.

The limb leads –I, II, III, aVR, aVL, and aVF provide information about the superior, inferior, rightward, and leftward forces.

The six precordial leads are also called the chest leads. The electrodes for the these leads are placed directly over the heart itself. These leads encircle the precordium and provide information about the anterior, posterior, right and left forces.

The EMS STAT 12-Lead is a compact pocket-sized visual aide, used to assist the clinician in interpreting 12-lead ECGs. This visual aid is easy to use and can be placed on most 12-lead ECG. In addition, the EMS STAT 12-Lead creates a systematic approach to looking at and identifying abnormalities within a 12-lead ECG.

• Easy, convenient and safe to use
• Eliminates confusion of the 12-lead identification
• Systematic approach to looking at and identifying abnormalities
• Quick identification of cardiovascular system of the heart

American Heart Association recommendation for 12-lead ECGs in the field. “EMS responders should be trained and equipped to obtain 12-lead ECGs. An out-of-hospital 12-lead ECG and advanced notification of the ED can reduce time to reperfusion.” American Heart Association, Handbook of Emergency Cardiovascular Care for Healthcare Providers 2006 p.24