How to Place ECG Leads

The ECG lead placement is important as it impacts patient care. ECG helps healthcare professionals identify various cardiac conditions. Proper ECG lead placement ensures accurate readings.

‍

Improper placement is one of the causes of misinterpretation, misdiagnosis, and delayed treatment. Since the first ECG was taken, huge strides have been made in recording and interpreting it. A 12-lead ECG is regarded as a standard tool among healthcare providers.

Misplaced leads can distort waveforms and falsely mimic dangerous conditions like ST elevation myocardial infarctions or mask significant findings. Gauze in this blog explains the steps of ECG lead placement, common errors, and their consequences to ensure you have accurate and reliable results.

‍

What are ECG Leads?

The term lead is not the wires that connect the ECG machine to the patient; however, a lead in ECG refers to the various viewpoints of the heart's activity. Every lead has a name to it.

‍

The term electrode refers to the self-sticky patches on the patient’s skin. These electrodes are connected to the ECG machine via lead wires.

‍

A 12-lead ECG:-

• Electrodes are sticky conductor pads attached to the body in specific areas. They record the heart's electrical activity.

• The colour-coded lead wires connect to the electrodes and transmit electrical activity to the ECG machine.

• The lead wires must be connected to the correct electrodes marked with their distinct location and colour.

‍

Setting up a 12-Lead ECG:-

A 12-lead ECG uses 10 electrodes:

‍

• 4 are placed on the limbs.

• 6 are placed on the chest.

‍

Steps for ECG lead placement:-

The following steps are followed for lead placement.

‍

• Prepare the skin.

• Attach the electrodes.

• Connect lead.

• Check for accuracy.

‍

1. Preparing the patient:-

• Patient position: The patient is positioned in a supine position.

• Remove all electronic devices, such as smartphones, which produce interference, giving improper readings.

• Arm and leg position: The arms should lie flat on the side, and the patient should be asked to relax the shoulders and keep legs uncrossed. It reduces muscle tension and movement that can interfere with the readings.

• Patient stillness, the patient is asked to lie still, as movements cause artifacts and interfere with the accuracy of the reading.

‍

2. Skin Preparation

• Electrodes should be in contact with the patient’s dry, hairless, and oil-free skin. Shave the hair on the chest that interferes with electrode placement.

• For better electrode adhesion, keep the skin oil-free. Rub the area with alcohol.

• Control the temperature of the environment to prevent the patient from sweating.

‍

3. Lead placement:-

Colour coding standards for 12-lead ECG

‍

• The IEC system is a worldwide recognised standard for ECG lead placement for clear identification.

• The AHA system is used in North America and is known for its ease of use.

‍

The IEC (International Electrotechnical Commission) and AHA (American Heart Association) systems have different colour-coding systems for 12-lead ECGs. Each lead is assigned a specific colour and position for cardiac monitoring.

‍

12-lead ECG placement mnemonic:-

AHA system for four electrode placement.

‍

• Smoke over fire, black lead, followed by red lead on the left arm and leg.

• Snow over grass, white lead followed by green lead on the right arm and leg.

‍

IEC system, for four electrode placement

Ride Your Green ‍ike- Red (right arm), Yellow (left arm), Green (foot), Black (neutral).

‍

Limb lead placement:-

• Right Arm (RA),  

• Left Arm (LA) 

• Right Leg (Neutral)

• Left Leg (LL) 

‍

They are attached to the arms and legs in the region proximal to the wrist and ankle. They can be placed on the limb but not on the bone, and should be symmetrically placed on either side.

‍

International Electrochemical Commission( IEC) colour code:-

The IEC code is used worldwide. Colour coding the electrode simplifies-

‍

• Process of placement.

• Reduces the risk of errors.

‍

The colour code for leads is

• Right arm (RA): red

• Left arm (LA): Yellow

• Right leg RL: Black

• Left leg LL: Green

• V1:Red

• V2:Yellow

• V3:Green

• V4: Brown

• V5:Black

• V6: Purple

‍

Chest leads and their placement

1. Placement of lead V1: Feel the top part of the breast bone, locate the sternal notch. Move your fingers downwards to feel a bump. Then, move to the right of the bump to find soft tissue between the second and third ribs; this is the second intercostal space. Move the finger over the third rib into the third intercostal space and then over the fourth rib into the fourth intercostal space. The electrode is placed in this intercostal space to the right of the sternal border.

‍

2. Placement of lead V2. After the lead V1 is placed, the electrode for lead V2 is placed at the same level on the left side of the sternum in the 4^th intercostal space.

‍

3. Placement of lead V4. Begin by locating the 5^th intercostal space on the left side of the chest. Identify the mid-clavicular line by finding the midpoint of the left clavicle and drawing an imaginary vertical line downwards. Place lead V4 at the intersection of the 5^th intercostal space and the mid-clavicular line.

‍

4. Placement of lead V3: Place lead V3 midway between the positions of V2 and V4. V4 is positioned before V3.

‍

5. Placement of lead V5. For lead V5, move from the position of lead V4 at the fifth intercostal space along the mid-clavicular line laterally to the anterior axillary line, an imaginary vertical line running down from the front edge of the armpit. Place the V5 lead.

‍

6. Placement of lead V6: Move laterally in the fifth intercostal space to the mid-axillary line, a vertical line descending from the middle of the armpit. Place the lead V6 at this point.
‍

Chest electrodes and their placement
V1: 4^th intercostal space on the right sternum.
V2: 4^th intercostal space at the left sternum.
V3: midway between V2 and V4.
V4: at the 5^th intercostal space at the mid-clavicular line.
V5: on the anterior axillary line at the same horizontal level as V4.
V6: on mid mid-axillary line at the same horizontal level as V4 and V5.

‍

4. Errors in lead placement and their effects:-

Expert technicians do not always record ECGs. Errors are often inevitable and adversely impact the readings. We must know how to spot them. The REVERSE mnemonic will help us to identify abnormal ECG findings and common placement errors.

‍

Misplacement of V1 and V2

Misplacement of V-1 and V2: Placement is vital for the best result; wrong placement can lead to incorrect readings. These leads provide important insights into the heart's right ventricle and septal regions. When placed too high or too low, they misinterpret electrical activity, leading to misdiagnosis of conditions like anterior wall infarctions.

‍

Errors due to signals

Errors can arise due to poor skin contact, electrode displacement, or electrical interference. They distort the ECG readings, making it difficult to interpret.

‍

5. Checking for Accuracy

• Before hitting the ON button, ensure all leads are connected to the right electrodes. 

• There are no loose connections.

• A patient does not move.  

‍

Conclusion

Proper ECG placement is essential for heart monitoring and diagnosing diseases. We must follow the right methodology and guidelines when we place the limb and precordial leads. This ensures the reliability of the ECG results. Proper lead placement also helps to reduce artifacts and minimize electrical interference, giving high-quality readings.

‍

It is necessary to refine ECG skills to provide timely and precise diagnoses. With the right technique and dedication to learning, healthcare providers can enhance patient care and services. Gauze offers the support needed for consistent and accurate ECG monitoring.