12 lead ECG Placement

Accurate lead placement is essential to ensure correct recording and interpretation of an ECG. 
Illustrated below: 


 

Limb Leads 
Right Arm (RA): Place the red (US=white) electrode just above the right wrist. 
Left Arm (LA): Place the yellow (US=black) electrode just above the left wrist. 
Right Leg (RL): Place the black (US=green) electrode on the right ankle. 
Left Leg (LL): Place the green (US=red) electrode on the left ankle. 

Precordial (Chest) Leads 
V1 (Red): Place in the fourth intercostal space at the right sternal border. 
V2 (Yellow): Place in the fourth intercostal space at the left sternal border. 
V3 (Green): Place halfway between V2 and V4. 
V4 (Blue): Place in the fifth intercostal space at the midclavicular line. 
V5 (Orange): Place horizontally with V4 at the anterior axillary line. 
V6 (Purple): Place horizontally with V4 at the midaxillary line. 

Which lead monitors which part of the heart?
 
 
 
Tips for Accurate Electrode Placement: 
Prepare the Skin: Clean the skin to remove any oils and dirt. Shave excessive chest hair if necessary to ensure good electrode contact. 
Correct Positioning: Make sure the patient is lying down (semi-recumbent) comfortably. For limb leads, ensure the arms and legs are relaxed to avoid muscle interference. 
Check Connections: Ensure all electrodes are securely attached and the connections to the ECG machine are firm. 
Monitor Lead Placement: Be mindful of the exact anatomical landmarks for placing precordial leads to avoid misplacement. 
Check ECG settings are correct (speed 25mm/second; this is usually preset when the machine is switched on) 
Recheck During Recording: Observe the electrodes during the ECG recording to ensure they remain in place, especially if the patient moves. 
 
Common Issues and Troubleshooting 
Despite best efforts, issues with ECG readings can still arise. Here are some common problems and their solutions: 
Artifact: Electrical interference or patient movement can cause artifacts. Ensure the patient is still and the environment is free from electrical devices that might interfere. 
Poor Contact: Dry or hairy skin can lead to poor electrode contact. Reclean the skin, replace the electrodes if necessary. 
Incorrect Lead Placement: Misplacement of leads can significantly alter the ECG reading. Double-check the placement according to the colour codes and anatomical landmarks. 
Loose Connections: Ensure that all connections between the electrodes and the ECG machine are secure and not loose.