ECG Lead positioning (2024)

The ECG is one of the most useful investigations in medicine. Electrodes attached to the chest and/or limbs record small voltage changes as potential difference, which is transposed into a visual tracing

Basic landmarks

3-electrode system

Uses3electrodes (RA, LA and LL)
Monitor displays the bipolar leads (I, II and III)
To get best results – Place electrodes on the chest wall equidistant from the heart (rather than the specific limbs)

5-electrode system

Uses5electrodes (RA, RL, LA, LL and Chest)
Monitor displays the bipolar leads (I, II and III)
ANDa single unipolar lead (depending on position of the brown chest lead (positions V1–6))

12-lead ECG

10electrodes required to produce 12-lead ECG
- 4Electrodes on all 4 limbs (RA, LL, LA, RL)6Electrodes on precordium (V1–6)
Monitors 12 leads (V1–6), (I, II, III) and (aVR, aVF, aVL)
Allows interpretation of specific areas of the heart
- Inferior (II, III, aVF)Lateral (I, aVL, V5, V6)Anterior (V1–4)

12-lead Precordial lead placement

V1: 4th intercostal space (ICS), RIGHT margin of the sternum
V2: 4th ICS along the LEFT margin of the sternum
V4: 5th ICS, mid-clavicular line
V3: midway between V2 and V4
V5: 5th ICS, anterior axillary line (same level as V4)
V6: 5th ICS, mid-axillary line (same level as V4)

Additional Lead placements

Right sided ECG electrode placement

There are several approaches to recording a right-sided ECG:

A complete set of right-sided leads is obtained by placing leads V1-6 in a mirror-image position on the right side of the chest (see diagram, below).
It can be simpler to leave V1 and V2 in their usual positions and just transfer leads V3-6 to the right side of the chest (i.e. V3R to V6R).

The most useful lead is V₄R, which is obtained by placing the V4 electrode in the 5th right intercostal space in the mid-clavicular line.
ST elevation in V4R has a sensitivity of 88%, specificity of 78% and diagnostic accuracy of 83% in the diagnosis of RV MI. [see Inferior STEMI]

V4R ECG lead placement

Erhardt et al first described the use of a right sided precordial lead (CR₄R or V₄R) in the diagnosis of right ventricular infarction which had previously been thought to be electrocardiographically silent. [Single right-sided precordial lead in the diagnosis of right ventricular involvement in inferior myocardial infarction. Am Heart J. 1976]

Posterior leads

Leads V7-9 are placed on the posterior chest wall in the following positions:

V7 – Left posterior axillary line, in the same horizontal plane as V6.
V8 – Tip of the left scapula, in the same horizontal plane as V6.
V9 – Left paraspinal region, in the same horizontal plane as V6.

See Posterior STEMI

Lewis lead (S5-lead)

The Lewis lead configuration can help to detect atrial activity and its relationship to ventricular activity. Named after Welsh cardiologist Sir Thomas Lewis (1881-1945) who first described in 1913. Useful in:

Lewis lead placement

Right Arm (RA) electrode on manubrium
Left Arm (LA) electrode over 5th ICS,right sternal border.
Left Leg (LL) electrode over right lower costal margin.
Monitor Lead I

Original Lewis Lead description (1913)

Thomas Lewis developed and described (1913) his lead configurationto magnify atrial oscillations present during atrial fibrillation.

When fibrillation is present and the electrodes lie in the vicinity of the right auricle (leads 1 and 2 of the diagram) the oscillations are maximal, and there is but a trace of the ventricular beats. When they lie in the long axis of the heart (lead 3) then both the oscillations and the ventricular complexes are conspicuous. Finally, when they lie along the left or right ventricular border (leads 4 and 5) the ventricular complexes are clear cut while the oscillations are small or absent.
The corresponding electrocardiograms are shown below the diagram, the first curve of which is from the customary lead II (right arm to left leg). The oscillations of fibrillation are readily identified in this manner and their origin in the auricle is clearly indicated. In tremulous subjects, no oscillations are seen in any of the special leads.
Lewis 1913

The first electrocardiogram is from lead II; it consists of irregularly placed ventricular complexes (R, T) and of large and continuous oscillations (f f).

The remaining five curves are from the chest wall.

1 and 2 were taken from the area overlying the right auricle; in these leads the oscillations are maximal and the ventricular complexes are minimal.
3 was taken from an oblique lead covering the whole heart, and it shows both oscillations and ventricular complexes.
4 and 5 were taken from leads along the margins of the ventricles; they show but little sign of the oscillations.

Fontaine leads

Fontaine bipolar precordial leads (F-ECG) are used to increase the sensitivity of epsilon wave detection. Named after French cardiologist and electrophysiolgist Guy Hugues Fontaine(1936-2018). Leads are placed as shown:

Right Arm (RA) over the manubrium;
Left Arm (LA) over the xiphoid process;
and Left Leg (LL) in the standard V4 position (5^th ICS MCL).

Instead of regular leads I, II, and III there are now three bipolar chest leads that are termed FI, FII, and FIII which record the potentials developed in the right ventricle, from the infundibulum to the diaphragm.

The vertical bipolar lead FI, (similar to aVF) magnifies the atrial potentials and can be used to record:

epsilon waves;
search for AV dissociation in ventricular tachycardia;
and to study abnormal atrial rhythms when the P waves are too small on regular leads.

ECG Electrode Guide

ECG Academy Videos

The ECG Lead

The Limb Leads

The Precordial Leads

Related Topics

ECG Limb Lead Reversals
Upper Limb Lead reversal

Advanced Reading

Online

Wiesbauer F, Kühn P. ECG Mastery: Yellow Belt online course. Understand ECG basics. Medmastery
Wiesbauer F, Kühn P. ECG Mastery: Blue Belt online course: Become an ECG expert. Medmastery
Kühn P, Houghton A. ECG Mastery: Black Belt Workshop. Advanced ECG interpretation. Medmastery
Rawshani A. Clinical ECG Interpretation ECG Waves
Smith SW. Dr Smith’s ECG blog.

Textbooks

Zimmerman FH. ECG Core Curriculum. 2023
Mattu A, Berberian J, Brady WJ. Emergency ECGs: Case-Based Review and Interpretations, 2022
Straus DG, Schocken DD. Marriott’s Practical Electrocardiography 13e, 2021
Brady WJ, Lipinski MJ et al. Electrocardiogram in Clinical Medicine. 1e, 2020
Mattu A, Tabas JA, Brady WJ. Electrocardiography in Emergency, Acute, and Critical Care. 2e, 2019
Hampton J, Adlam D. The ECG Made Practical 7e, 2019
Kühn P, Lang C, Wiesbauer F. ECG Mastery: The Simplest Way to Learn the ECG. 2015
Grauer K. ECG Pocket Brain (Expanded) 6e, 2014
Surawicz B, Knilans T. Chou’s Electrocardiography in Clinical Practice: Adult and Pediatric 6e, 2008
Chan TC. ECG in Emergency Medicine and Acute Care 1e, 2004

LITFL Further Reading

ECG Library Basics – Waves, Intervals, Segments and Clinical Interpretation
ECG A to Z by diagnosis – ECG interpretation in clinical context
ECG Exigency and Cardiovascular Curveball – ECG Clinical Cases
100 ECG Quiz – Self-assessment tool for examination practice
ECG Reference SITES and BOOKS – the best of the rest

ECG LIBRARY

more EKG…

Mike Cadogan

BA MA (Oxon) MBChB (Edin) FACEM FFSEM. Emergency physician, Sir Charles Gairdner Hospital. Passion for rugby; medical history; medical education; and asynchronous learning #FOAMed evangelist. Co-founder and CTO of Life in the Fast lane | Eponyms | Books | Twitter |

FAQs

What is the anatomical position of the ECG leads? ›

Placement of chest (precordial) electrodes

V1: fourth intercostal space, to the right of the sternum. V2: fourth intercostal space, to the left of the sternum. V3: placed diagonally between V2 and V4. V4: between ribs 5 and 6 in the midclavicular line.

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What is the position of the leads in the ECG monitor? ›

Apply the LL electrode just below the rib cage on the left side. Apply the chest lead electrode on the V₁ position at the fourth ICS right sternal border. Apply the second chest lead electrode on the V₆ position at the fifth ICS left midaxillary line. Rationale: Only one precordial lead may be displayed.

Keep Reading ›

Where do the 12 lead electrodes go on a female? ›

ECG Lead Placement on Women: Nuances to Understand

Regardless of a patient's sex, the positioning of the electrodes remains the same: V1 and V2 flank the sternal borders at the fourth intercostal space; V4, V5, and V6 align starting at the fifth intercostal space; and V3 goes on the midway point between V2 and V4.

What happens if ECG leads are put on incorrectly? ›

Electrocardiography (ECG) is a very useful diagnostic tool. However, errors in placement of ECG leads can create artifacts, mimic pathologies, and hinder proper ECG interpretation.

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What is the mnemonic for ECG leads? ›

Once all electrodes have been applied, attach the associated limb leads, with the cable for each lead lying inferior to the electrode (to reduce tension on the wire). Some people find the mnemonic “Ride Your Green Bike” useful for remembering the placement of the limb leads, starting clockwise from the right wrist.

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Where do you put right and posterior ECG leads? ›

Right sided ECG leads (V1R-V6R) are positioned in a mirror image fashion from the standard 12-lead precordial leads. Posterior ECG leads (V7-V9) are applied by moving V4-V6 in the posterior positions.

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What are the 5 lead ECG placement names? ›

5-Lead Placement

Location	Code (AHA)	Colour (IEC)
Right arm (inner wrist)	RA	Red
Right leg (inner ankle)	RL	Black
Left arm (inner wrist)	LA	Yellow
Left leg (inner ankle)	LL	Green

1 more row

Apr 27, 2023

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Which lead is the most important in ECG? ›

To assess the cardiac rhythm accurately, a prolonged recording from one lead is used to provide a rhythm strip. Lead II, which usually gives a good view of the P wave, is most commonly used to record the rhythm strip.

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What is the position of the patient for an ECG? ›

Place the patient on a padded surface; don't let the patient or the clips touch metal. Place the patient in right-lateral recumbency when possible. Please note this is the only position valid to determine the ECG axis.

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What is the correct lead placement for the telemetry leads? ›

Place the right arm (RA) electrode near the right shoulder, close to the junction of the right arm and torso. Place the left arm (LA) electrode near the left shoulder, close to the junction of the left arm and torso. Place the right leg (RL) electrode below the level of the lowest rib on the right abdominal area.

Does ECG lead placement matter? ›

Conclusions. We provide better and more robust evidence that routine modification of limb electrode placement produces only minor changes to the ECG waveform in healthy subjects. These are not clinically significant according to the 2009 guidelines and thus have no effect on the clinical specificity of the 12 lead ECG.

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Do I have to remove my bra for an EKG? ›

What will happen during an EKG? You will be asked to remove your shirt or blouse, and lie down on your back. If you are wearing a sport bra, you can leave it on and the technician will work around it. Small plastic tabs called electrodes are placed on the chest, arms, and legs with a special tape.

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Why are ECG leads placed on arms and legs? ›

Six chest or precordial leads allow clinicians to view the heart in the horizontal plane, while four limb leads provide a vertical view. This creates an unparalleled three-dimensional representation of atrial and ventricular depolarization and repolarization that a trained clinician can interpret in just a few minutes.

Should ECG leads be placed over bone? ›

Patient-specific Considerations When Placing ECG Electrodes. Certain patient factors may influence the accuracy of information captured during a standard 12-lead ECG. Adults commonly lose body mass as they age—electrodes should never be placed over bony prominences on any older patient.

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Why is ECG connected to the left ankle? ›

A standard ECG is obtained by attaching three electrodes- one to each wrist and another to the left ankle. This is done in order to minimize any noise detection by the activity of action potentials generated by the skeletal muscles.

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Where do ECG leads go for stress test? ›

RA and LA electrodes should be placed just below the right and left clavicle. RL and LL electrodes should be placed on the lower edge of the rib cage, or at the level of the umbilicus at the mid-clavicular line.

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