The increasing practice of placing limb leads (aVL, aVR, aVF) on the upper chest (shoulders) and lower abdomen is NOT acceptable and may result in distorted ECG morphology (it may alter ST segment falsely indicating infarction or ischaemia). The angle of Louis, which is adjacent to the second rib, and the second ICS, which is just below the second rib, are located. Once the second ICS has been located, the operator can palpate down the chest wall adjacent to the sternum until he or she arrives at the fourth ICS.

• When the operator is facing the patient, the electrode for V1 is placed in the fourth ICS to the left of the sternum (patient’s right) and the electrode for V2 is placed in the fourth ICS to the right of the sternum (patient’s left).
• The next electrode placement is V4, which is located in the fifth ICS in the midclavicular line on the patient’s left precordium.
• The electrode for V3 is then located midway between the electrodes for V2 and V4.
• The remaining 2 electrodes for V5 and V6 are located in a straight line from V4. The electrode for V5 is located in the anterior axillary line, even with V4, and the electrode for V6 is located in the midaxillary line, even with V5.

ECG electrodes should be placed UNDER the breast as close to the chest wall as is possible.