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Heart Education Awareness Resource and Training through E-learning

09: Cardiac Investigations: Electrocardiography

3 and 5 Lead ECG

Three or five lead monitoring can be applied for use with both static and telemetry cardiac systems. The 3 or 5 lead systems are attached to electrodes which are applied to specific locations on the patient's chest. It is important to ensure proper skin preparation prior to application of the skin electrodes.

3 and 5 lead ECG interactive

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Skin preparation

Proper skin prep is essential to obtain good quality tracing:

  • Choose designated chest electrode placement sites
  • Avoid placing electrodes over bony prominences i.e. clavicles
  • To enhance electrode skin contact and patient comfort:
    • Clip /shave excess chest hair in a 1-2 cm diameter of the designated electrode site, if necessary, with the patients consent
    • With a dry swab, gently clean /abrade electrode sites to remove loose skin cells, body oil, sweat and improve skin/electrode contact
    • If alcohol pad is used to cleanse skin, allow to site to dry, before electrode placement. ECG Electrodes are small sensor pads (self adhesive,disposable, pre gelled) applied on the skin to enable detection of the electrical activity of the heart, which is transmitted to the monitor, amplified and displayed as the ECG trace

3 lead Placement (I, II, or III):

Monitors one of the three leads:

  • RA: red electrode:
    • placed under right clavicle near right shoulder, within the rib cage frame
  • LA: yellow electrode:
    • placed under left clavicle, near left shoulder, within the rib cage frame
  • LL: green electrode:
    • placed on the left side, below pectoral muscles, lower edge of left rib cage

5 lead Placement:

  • RA: red electrode:
    • placed under right clavicle, near right shoulder, within the rib cage frame
  • LA: yellow electrode:
    • placed under left clavicle, near left shoulder, within the rib cage frame
  • LL: green electrode:
    • placed on the left side, below pectoral muscles, lower edge of left rib cage
  • V: white electrode:
    • placed on the 4th intercostal space, at right sternal border
  • RL: black electrode:
    • place on a non muscular surface on the lower edge of the right ribcage

How to set up a cardiac monitor:

Prepare Cardiac Monitor as directed by manufacturer

  • Attach designated lead cable and wires to electrodes
  • Select desired monitoring lead system - usually lead 11
  • Verify there is a clear ECG tracing & prominent QRS complex
  • Set Rate Alarm limits within safe parameters (acceptable to the individual patient’s clinical condition)
  • Confirm pre-determined arrhythmia analysis/default menu settings as per local protocol

See Additional information for common problems associated with cardiac monitoring.

Having set up your specific monitoring system, we will now go on to consider how to interpret the cardiac rhythm using a systematic 6 step approach.

Pulse point

Always refer to the manufacturer's instructions for specific information related to the use of the monitoring system.



6 step approach


Module name: Cardiac Investigations

Map name: 09: Cardiac Investigations: Electrocardiography

Map ID: 1797

Node ID: 47895