Identifying the Placement Site for the Quadtrode Electrode
Ensure that the location of the electrodes is compliant to the requirements of your
electrosurgical equipment to reduce the possibility of burns; however, note that monitoring
in the MR environment requires specific electrode placement. (See page 5-3 to ensure the
highest quality ECG signal. For questions and guidance regarding placement, contact
technical support; see page 14-16 for contact information.)
According to the patient type or weight, placement of the Quadtrode electrode over the heart is
important for optimal ECG performance.
For placement purposes, we define to the breast line as an imaginary horizontal line that extends
across the nipple areas of a patient of normal weight.
Adult and pediatric patients:
Neonatal and infant patients:
Deviations from the guidelines for Quadtrode electrode placement can affect the produced ECG
signal as follows:
Expression MR400 Instructions for Use Monitoring ECG 5‐7
If using a standard Quadtrode electrode, place it slightly to the left of the patient's
sternum, with the top two electrodes on the breast line and the bottom two electrodes
below the breast line.
If using a CV Quadtrode electrode, attempt to keep a small separation between individual
electrodes—a distance that is wide enough to properly capture the ECG vector, but not so
wide as to cause excessive noise pickup. (Increasing the loop area between electrodes has
a negative effect on ECG quality unique to the MRI environment that causes more noise to
be picked up by the ECG leads).
Depending on the patient's weight, center a standard Quadtrode electrode or a neonate
Quadtrode electrode over the sternum and the breast line.
Placements offset above the breast line: Increases the T‐wave amplitude and the
susceptibility to static field (B0) effects.
Placements offset below the breast line: Decreases the T‐wave amplitude, increase the
distance from the aortic valve, the susceptibility to static field (B0) effects and the ECG
Placements closer to the sternum: Increases the ECG wave amplitude and also any
Placements farther from the sternum: Decreases the ECG wave amplitude and any