Welch Allyn Arrhythmia Monitoring Chart Quick Reference Guide

P-R

Interval

QRS Duration

P

S

T

R

Q

Q-T

Interval

Arrhythmia Monitoring

on the Welch Allyn Acuity® Central Station

Using Mortara Instrument’s VERITAS™ ECG analysis algorithms

NORMAL SINUS RHYTHM

QRS NORMAL SINUS RHYTHM EXAMPLE

Arrhythmia Alarms Setup Window

ARRHYTHMIA EVENT DEFINITIONS

ARRHYTHMIA EVENT

VFib 1

(Ventricular

Fibrillation)

Lethal Arrhythmia

Asystole

Lethal Arrhythmia

VTach 2

(Ventricular

Tachycardia)

Lethal Arrhythmia

WAVEFORM EXAMPLES DEFINITION

Chaotic quivering of the ventricles
accompanied by rapid irregular
waves but no formed QRS
complexes.

Absence of any detected beat for
4 or more seconds.

Characterized by a run of premature
ventricular beats that exceeds the
PVC run alarm limit setting and
that meets or exceeds the patient’s
VTach alarm limit.

a

Irregular Limit:

PVC Run

(Ventricular Run)

VRhythm

(Ventricular

a

b

c

Rhythm)

Couplet Characterized by two consecutive

Characterized by a run of three
to six consecutive, premature
ventricular beats that meets or
exceeds the patient’s VTach
alarm limit.

Characterized by a run of successive
ventricular beats that is less than the
VTach alarm limit setting, and the
number of successive ventricular
beats is greater than or equal to three.

ventricular beats that are preceded
and followed by a normal beat.

Preferences vary regarding Acuity System alarming sensitivity for irregular rhythm arrhythmia
types. There is now a way to adjust the minimum time that an irregular rhythm occurs before your
Acuity System alarms, on a patient-by-patient basis.

b

Single ECG:

The system uses up to three ECG leads to detect normal beats, ventricular beats and to analyze
arrhythmias. If false arrhythmia alarms are occurring due to a patient’s unique beat morphology,
you can direct the Acuity System to analyze arrhythmias using one reliable lead.

WARNING If you turn on Single ECG in response to false lethal arrhythmia alarming (for example,

due to bundle branch block or irregular rate), arrhythmia analysis is limited to one lead. Typically,
3-lead analysis (via a 5-lead cable) is optimal.

c

Analyze Pacers:

Always turn on Analyze Pacers for paced patients, and always turn off Analyze Pacers for non­paced patients. The Acuity System analyzes arrhythmias based on whether the Analyze Pacers
setting is on or off. The Analyze Pacers setting is Off by default.

PVC/min

(Ventricular

Beats per

Minute)

Bigeminy

Trigeminy

Premature ventricular contractions
(PVCs, either unifocal or multifocal)
that are greater or equal to the
patient’s PVC/min alarm limit setting.

Characterized by three or more
successive cycles consisting of a
normal beat followed by a premature
ventricular beat. Bigeminy is
independent of the average heart rate.

Characterized by three or more
successive cycles of two normal beats
followed by a premature ventricular
beat. Trigeminy is independent of the
average heart rate.

ECG Lead Selection
and Placement

If monitoring with Propaq® LTR or Micropaq®, Acuity will use ECG leads II, V and III for
arrhythmia analysis.

®

If monitoring with Propaq
for ECG1 and/or ECG2. To optimize arrhythmia analysis performance: verify that the ECG lead(s) have
significant amplitude. Otherwise, an incorrect heart rate or arrhythmia alarm condition could occur.

If the QRS complex is less than twice the amplitude (height) of the P and T waves, a different monitoring
lead should be selected. Tall P and T waves may be incorrectly classified as a QRS complex or PVC and
potentially generate a high heart rate or other alarm condition.

CS and/or Propaq Encore®, Acuity uses the leads that the user selects

Tachycardia

Bradycardia

Irregular

(Irregular

Rhythm)

Characterized by a HR greater than or
equal to the patient’s tachycardia alarm
limit value. (If the tachycardia limit is
decreased past the HR high limit, then
the HR high limit will decrease to a value
equal to the tachycardia limit.)

Characterized by a HR less than or
equal to the patient’s bradycardia alarm
limit value. (If the bradycardia limit is
increased past the HR low limit, then
the HR low limit will increase to a value
equal to the bradycardia limit.)

An irregularity in the R-to-R
interval over a series of at least
16 nonventricular beats.

The Relearn Function

The Relearn function enables the clinician to tell Acuity to relearn a patient’s rhythm based
on the patient’s dominant beat morphology.

During the learning period, Acuity indicates only the VFib and Asystole arrhythmia conditions.
Other vital signs are unaffected.

Acuity automatically relearns the patient’s normal reference beats whenever the alert
presents itself under the following conditions:

 • Afterpatientconnectionorsystemrestart
 • Aftersomeleadchangesorleadfailures
 • AfterST/Arr Relearn or Analyze Pacers or Single ECG is clicked in the Arrhythmia

Alarms Setup window

WARNING Inappropriate use of Relearn can lead to mislabeling of beats and possibly a

failure to alarm. Carefully evaluate the patient’s current rhythm to make sure that you want
the Acuity System to establish it as the patient’s normal sinus rhythm.

Pause

Noncapture

(Pacemaker

Noncapture)

An R-to-R interval that is greater
than or equal to two times the
average R-to-R.

For pacemaker patients with the
Analyze Pacers option enabled,
a beat does not directly follow
a pacer.

1. VFib is detected if the waveform fulfills the following conditions for at least 5 seconds:

• Absence of fast slew-rate activity (QRS-like activity). • Average peak-to-peak wave amplitude higher than 200 µV.

• Wave rate higher than 130 bpm. • Wave period variance higher than a specific threshold.

2. The American Heart Association describes sustained and nonsustained ventricular tachycardia as follows:
Ventricular tachycardia can be referred to as sustained or nonsustained. Sustained refers to an episode that lasts at least 30
seconds and generally requires termination by antiarrhythmia drugs, antitachycardia pacing techniques or electrical cardioversion.
Nonsustained ventricular tachycardia suggests that the episodes are short (three beats or longer) and terminate spontaneously.

The average heart rate is calculated on the basis of the mean R-to-R interval of the last 16 beats. If the heart rate calculated
using the last four beats is less than or equal to 48, then this rate is used.

©2009 Welch Allyn, Inc. All rights reserved. Acuity, Micropaq, Propaq and Propaq Encore are all registered trademarks of Welch Allyn, Inc.
Other company names mentioned herein are for identification purposes only and may be the trademarks or registered trademarks of their respective companies.

Printed in USA SM2567 Rev C