A 12 Lead ECGElectrocardiogram; also called an EKG; a representation of electrical voltage measured across the chest over a period of time. 1. Six Second ECG Guidebook (2012), T Barill, p. 196 More provides a fairly good electrical picture of the left side of the heart. The right side of the heart is somewhat under served. If the 12 Lead suggests any pathology to the inferior view of the heart (left and right ventricleThe right ventricle ejects blood through the main branches of the left and right pulmonary arteries to the lungs. The chambers of the heart are the main drivers within an intricate pathway, delivering blood to the lungs for gas exchange... More), 3 additional lead viewsLocating the positive electrode is crucial to determining which area of the heart is viewed electrically. Metaphorically, the positive electrode serves as a mini-video camera aimed at the heart in the direction of the negative electrode. These leads and their... More should be added to map out the right lateral and posterior views. The resulting 15 lead ECG provides a more complete three dimensional picture of the heart.
The inferior leadsThe inferior leads show the inferior aspects of the heart - the inferior aspects of the right ventricle and the left ventricle. Much of the inferior view of the heart is of the right ventricle. Precordial leads placed along the... More show the inferior aspects of the heart – the inferior aspects of the right ventricle and the left ventricleThe left ventricle ejects blood into the aortic arch to the body. Within the arch, the coronary arteries branch off first followed by three main arteries that branch to the brain (carotids) and the upper thorax (subclavian artery). The chambers... More. Much of the inferior view of the heart is of the right ventricle. Precordial leads placed along the right side of the chest help complete the picture of the right ventricle. Posterior views of the heart can be best seen via posterior leadsPosterior views of the heart can be best seen via posterior leads placed below the scapula to the left of the spine. The inferior leads show the inferior aspects of the heart - the inferior aspects of the right ventricle... More placed below the scapula to the left of the spine.
The addition of three right-sided precordial leads provides a complete view of the right ventricle. The addition of three posterior leads completes an 18 lead ECG. Note that most 12 lead ECG units do not provide the sixteen electrodes necessary for an 18 lead ECG, or the thirteen electrodes required for a 15 lead ECG. Instead, two separate 12 lead ECGs are taken – the first with standard lead placement and the second with the precordial electrodes repositioned to address the right and posterior aspects of the heart. The extra lead views of a 15 or 18 lead ECG are then labelled accordingly.