Editing Electrocardiography (section)

==={{anchor|Lead groups}}Contiguity of leads===
[[File:Contiguous leads.svg|300px|thumb|Diagram showing the contiguous leads in the same color in the standard 12-lead layout]]
Each of the 12 ECG leads records the electrical activity of the heart from a different angle, and therefore align with different anatomical areas of the heart. Two leads that look at neighboring anatomical areas are said to be ''contiguous''.<ref name="Meek 415–418"/>

{| class="wikitable"
|-
! Category
! Leads
! Activity
|-
| Inferior leads
| Leads II, III and aVF
| Look at electrical activity from the vantage point of the [[wikt:inferior|inferior]] surface ([[diaphragmatic surface of heart]])
|-
| Lateral leads
| I, aVL, V<sub>5</sub> and V<sub>6</sub>
| Look at the electrical activity from the vantage point of the [[lateral (anatomy)|lateral]] wall of left [[ventricle (heart)|ventricle]]
|-
| Septal leads
| V<sub>1</sub> and V<sub>2</sub>
| Look at electrical activity from the vantage point of the [[septal]] surface of the heart ([[interventricular septum]])
|-
| Anterior leads
| V<sub>3</sub> and V<sub>4</sub>
| Look at electrical activity from the vantage point of the [[anterior]] wall of the right and left ventricles ([[Sternocostal surface of heart]])
|}

In addition, any two precordial leads next to one another are considered to be contiguous. For example, though V<sub>4</sub> is an anterior lead and V<sub>5</sub> is a lateral lead, they are contiguous because they are next to one another.