Preparing to Monitor ECG
For accurate V/C lead placement and measurement, it is important to locate the fourth intercostal
To locate the fourth intercostal space:
Locate the second intercostal space by first palpitating the Angle of Lewis (small bony
protuberance where the body of the sternum joins the manubrium). This rise in the sternum is
where the second rib is attached, and the space just below this is the second intercostal space.
Palpate and count down the chest until you locate the fourth intercostal space.
It is important to select a suitable lead for monitoring so that a QRS complex can be accurately
For non-paced patients:
QRS complex should be tall and narrow (recommended amplitude > 0.5mV).
R-Wave should be above or below the baseline but not biphasic.
P-Wave should be smaller than 1/5 R-wave height.
T-Wave should be smaller than 1/3 R-wave height.
NOTE: To prevent detection of P-Waves or baseline noises as QRS complexes, the minimum detection level
for QRS complexes is set at 0.15 mV, according to AAMI-EC 13/YY1079 specifications. If the ECG
signal is too weak, you may get false alarms for asystole.
For paced patients with internal/transvenous pacemakers:
Confirm paced status is set correctly on the Efficia DFM100, see
All four criteria for non-paced patients listed above.
Large enough to be detected (half the height of the QRS complex), with no re-polarization
artifact. Some unipolar pacemakers display pace pulses with re-polarization tails which may be
counted as QRSs in the event of cardiac arrest or other arrhythmias. Choose a lead to minimize
the size of re-polarization tails.
NOTE: Adjusting the ECG wave size on the display does not affect the ECG signal which is used for
Available monitoring leads vary depending on what type of ECG cable is connected to the Efficia
DFM100 and its configuration. See
If you are using
a 3-Lead ECG set
a 5-Lead ECG set
To select leads to display on the Efficia DFM100, see
WARNING: Avoid touching monitoring electrodes and other measuring devices when they are applied to the
patient. Doing so can degrade safety and may affect results.
on page 41.
These leads are available
I, II, III
I, II, III, aVR, aVL, aVF, V
"Selecting the Waveform"
4: ECG Monitoring
on page 53.