Datascope Passport - Mindray

Operation Arrhythmia Algorithm (Optional Passport 2)
Heart Rate Meter
Heart Rate is computed using the 16 most recent R-R intervals for heart rates above 48 beats
per minute. If the rate calculated using the last 4 beats is less than 48 beats per minute, then
this rate is used. All detected beats are used to compute the heart rate. A separate ventricular
rate is used in the algorithm to determine rhythms like ventricular tachycardia and ventricular
run.
Filtering Pacer Signals
In order to prevent pacer pulses from being mistaken for QRS complexes, they are removed
from the ECG data that is sent to the arrhythmia algorithm for analysis. Pacer pulses are
shown on the Passport 2 as exaggerated vertical lines.
ECG Amplitude
The QRS detection threshold algorithm setting is fixed between 0.15 and 0.45 mV to avoid
detecting noise spikes or P-waves as valid beats. Changing the display gain on the monitor
does not affect the signal that is used by the algorithm for beat detection. For optimal
performance, the leads selected for monitoring should have an amplitude of 0.5 to 1 mV or
more.
Learning
The process of learning is used to establish a normal beat template for a patient. The learn
period is dependent on the heart rate and the dominant pattern. Learning should not be
initiated during a primarily ventricular rhythm because an ectopic beat may be established
as normal.
A learn should be initiated when beats are not being properly detected, or when they are
being erroneously classified. However, if a signal is not strong enough, or lead data is
extremely noisy, better signal quality must be established before a learn can be effective.
Beat Detection and Typing
The following table describes the leads that are used to measure beat detection and beat
typing.
DESCRIPTION 3-WIRE LEAD SET 5-WIRE LEAD SET VIEW 12 CARD
Leads used for Beat
Detection
Leads used for Beat
Typing
Leads used for
V-Fib Detection
Determined by
viewed lead
Determined by
viewed lead
Determined by
viewed lead
II and V V1 and V5
II, V, and I V1, V5, and II
II and V V1 and V5
The search for the next beat begins after a refractory period to avoid detecting T- waves as
valid QRS complexes. For all patient sizes, the minimum QRS amplitude that can be detected
is between 0.15 and 0.45 mV depending on the width of the QRS complexes.
Beat typing aligns and compares each new heart beat to reference templates that were
previously stored in the system. A beat typing algorithm classifies the beats.
Passport 2 ® /Passport 2 LT Operating Instructions 0070-10-0649-01 3 - 35