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Defibrillation protection is guaranteed when the original Mortara ECG patient cables are used.
The system captures and presents data reflecting a patient’s physiological condition that when reviewed by a
trained physician or clinician can be useful in determining a diagnosis. However, the data should not be used as
a sole means for determining a patient’s diagnosis. The system is equipped with Mortara’s VERITAS™ 12-lead
resting ECG interpretation algorithm. The VERITAS ECG algorithm can provide an over-reading physician
with a silent second opinion through diagnostic statements output on the ECG report.
12-lead ECGs acquired through Surveyor will normally use a modified lead system with the limb electrodes
positioned on the torso. Although this is a generally accepted practice (e.g., in stress testing), the different
electrode positions can cause morphology changes on the ECG, thus influencing their interpretation. Most
frequently seen differences are a vertical and rightward axis shift, minor changes of evidence of old inferior
infarction and changes in the T-wave in the limb leads. All 12-lead ECGs printed with Surveyor have a warning
message that alerts the physician that the ECG might have been acquired with torso positioned limb leads. It is
recommended that you place the electrodes as close as possible to the normal limb positions avoiding the
possibility of causing artifact. The right arm and left arm electrodes should be placed on the clavicles as close
as possible to the arms. The left leg electrode should be placed as close as possible to the left leg without
subjecting it to the possibility of motion artifact.
During periods of lead fail and when a reduced lead set is used for patient monitoring, 12-lead resting ECG
interpretation cannot be reliably used in determining a diagnosis.
For full diagnostic quality, the resting ECG should be printed on the Surveyor Central Station printer and not on
the S12 or S19 strip chart recorder.
ECG Calculated Heart Rate Warnings
Heart rate indication is usually not affected by pacemakers with direct cardiac application, ventricular or
supraventricular arrhythmias or irregular heart rates; however, in some conditions a pacemaker pulse can give
rise to double QRS detections. Also, not activating the “Analyze Pacers” field in the signals menu in the
presence of a pacemaker might lead to beat detections without a QRS complex due to the detection of the
pacemaker spike.
Heart rate is calculated over 16 beats at rates over 40 bpm and 4 beats at lower heart rates. This results in a
response time of 9 seconds or less when the heart rate changes suddenly from 80 bpm to 40 or 120 bpm, as
measured according to ANSI/AAMI EC13 and IEC60601-2-27.
Tall and peaked T-waves may affect QRS detection resulting in doubled heart rates. Surveyor rejects tall
T-Waves less than or equal to 240% of a 1mV QRS in diagnostic mode, and 70% of a 1mV QRS in monitoring
mode, as well as a Q-T interval of 350 ms measured for both diagnostic and monitoring modes according to
ANSI/AAMI EC13 and IEC 60601-2-27.
The heart rate meter correctly detects all beats of the alternating beat type waveforms considered in
ANSI/AAMI EC 13 and IEC 60601-2-27 Figure 201.101 patterns A1-A4 if the QRS amplitudes exceed the
minimum detection threshold set by the user.
Time to tachycardia, as measured according to ANSI/AAMI EC13 and IEC 60601-2-27 Figure 201.101 patterns
B1-B2 is less than 8 seconds.
Heart rate indication is not reliable during episodes of ventricular fibrillation.
The summarized performance of the QRS recognition and classification algorithm on standard databases, as
defined by ANSI/AAMI EC 57, is as follows:
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