How to place the leads for a 12-lead ECG
Other platforms explain it with text and video. In VMS you practice it on the patient.
A wrong lead position can change the ECG enough to mimic a heart attack. Counting the rib spaces carefully is the whole skill.
Step by step
Prepare
Clean your hands, introduce yourself, explain, get consent, privacy, patient lying flat or slightly raised. [1]
Skin
Clean and dry the skin; clip hair where needed. [1]
Limb leads
Right arm, left arm, right leg and left leg on the limbs, not on the chest. [1]
V1 and V2
Fourth intercostal space just right (V1) and just left (V2) of the breastbone. Find the angle of Louis to locate the second rib, then count down. [2]
V4, then V3
V4 in the fifth intercostal space on the midclavicular line; V3 halfway between V2 and V4. [2]
V5 and V6
Same level as V4: V5 on the front of the armpit line, V6 on the middle of the armpit line. Place under breast tissue, not on top. [2]
Record
Patient still and quiet, check for a clean tracing, label with time and symptoms, show it to the clinician right away if there is chest pain. [1]
Common errors
- V1 and V2 placed too high.
- Limb leads on the chest without noting it.
- Patient talking or moving during the tracing.
Practice it in VMS
In VMS you do this on the patient, not on paper: every step goes on the checklist with a score, and in Teach mode Blocky tells you what comes next.
VMS cases that train this skill
Sources
Steps adapted from OpenStax, Clinical Nursing Skills, licensed under CC BY 4.0. Facts and steps also follow National EMS Education Standards (2021). VMS is not affiliated with these organizations. Updated: 2026-10-11.