de Switcch
Mode Switch is
i a rate conttrol feature designed to prevent
the tra
acking of paroxysmal atrial tachycard
dias. This
iss performed by
b placing the
e device in DDIR
mode until
the episo
ode is over, p
preventing a rapid ventriccular pace
ate in response to the rap
pid atrial rate..
Mode Switch, nominally On, functions when
the dev
vice is opera
ating in a traccking mode (DDDR, DDD
D, or
VDD). Mode Switch
has th
he following programmab
le settings:
 Detec
ct Rate – Spe
ecifies at wha
at rates to sw
witch modes.
 Detec
ct Duration – The minimu
um duration (in
( seconds) that the atria
al tachyarrhytthmia must p
e the Detect Rate
before the
t mode switches to DD IR.
 Blank
ked Flutter Search
– Settting that allow
ws device to mode switch
h if 2:1 blankking of a rapid
d atrial
hmia is detec
To program Mode
Switch in
i pacemake
ers, go to Parrams -> Mod e Switch.
To program Mode
Switch in
i ICDs, go to
o Params -> Pacing -> M
Mode Switch.
ote: The On/Off and parameter setting
screens may
m differ depend
ding on device tyype and model.
ded for patients known to
o have chroniic refractory atrial
 Mode Switch is not recommend
arrhythmias, such as atria
al tachycardia
a, atrial fibrilllation, or atria
al flutter.
 Mode Switch can be
b programm
med concurre
ently with Man
naged Ventrricular Pacing
g (MVP)® in tthe
<=>DDDR an
nd AAI<=>DD
DD modes. During
atrial ttachyarrhythm
mias, the paccemaker switches to
DDIR pacing regarrdless of the current operrating MVP m
© 2013 Medtron
nic, Inc.
ww w.medtronic
Page 1 of 4
When Mode Switch is On, several rates, timing intervals, and pacing therapies are limited to certain
values (ie, Mode Switch Detect Rate, Post Mode-Switch Overdrive Pacing (PMOP) Overdrive Rate,
Rate Drop Response, PVAB, SAV and PAV intervals, Sensor-Varied PVARP). Please reference
device manual for specifics.
Feature Operation
When the device detects an atrial tachyarrhythmia, it
switches from the programmed atrial tracking mode to
a non-atrial tracking mode (DDIR or VDIR) and remains
in this mode until the atrial tachyarrhythmia ceases.
Then the device switches back to the atrial tracking
mode, as shown in the table below, unless Post ModeSwitch Overdrive Pacing (PMOP) has been
The device defines an atrial tachyarrhythmia based on the device type and model as described below.
Adapta®, Versa® and Sensia®:
 4/7 detection criteria – 4 out of 7 consecutive A-A intervals ≤ the detection rate
 Arrhythmia confirmation criteria – Atrial rate is equal or greater to detection rate and satisfying
duration criteria.
Blanked flutter search – Monitors for A–A intervals that may indicate 2:1 blanking of atrial events. If
certain criteria are met, the device extends PVARP and the VA interval to uncover any blanked AS
events. If an A-A interval shorter than the detect rate interval is detected, 2:1 sensing of an atrial
tachyarrhythmia is assumed. Otherwise, the pacemaker resumes monitoring for 2:1 sensing of atrial
tachyarrhythmias in 90 seconds.
Detect duration – Required delay for Mode Switch to occur. During this delay, device is monitoring
every 8th A-A interval < detection interval.
End of Mode Switch criteria – 7 consecutive A-A intervals longer than the upper tracking rate OR 5
consecutive atrial paces.
Advisa DR MRITM, Revo MRI®, EnRhythm® Consulta® CRT-P, Syncra® CRT-P and Medtronic ICDs
Arrhythmia criteria: Mode Switch occurs when the device detects the onset of an atrial tachyarrhythmia
episode. The detection of AT/AF onset is based on the programmed AT/AF detection interval and the
accumulation of additional evidence of atrial tachyarrhythmia based on the number and timing of atrial events
within the ventricular intervals. If the atrial rate is above the AT/AF detection interval and there are more atrial
events than ventricular events in three V-V intervals, Mode Switch will occur.
The example on the next page demonstrates the steps of a Mode Switch episode:
© 2013 Medtronic, Inc.
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 Post Mode-Switch Overdrive Pacing (PMOP) allows Mode Switch to provide extended DDIR pacing at
a higher rate after the atrial arrhythmia subsides.
 A Mode Switch operation cannot start during an ATP therapy in ICDs. If a Mode Switch episode starts
before the ATP therapy begins, the device suspends Mode Switch operation during the therapy and
resumes it after the therapy delivery.
 Mode Switch and Managed Ventricular Pacing (MVP)® modes (AAIR<=>DDDR or AAI<=>DDD)
interact to adjust the pacing mode according to the patient’s atrial rhythm and AV conduction status.
 The Mode Switch parameter should be programmed to On if the patient has a history of atrial
arrhythmias or atrial arrhythmias are suspected.
Advisa MRITM SureScan® Pacing System,
Revo MRI® SureScan® Pacing System,
Adapta® DR, Versa® DR, Sensia® DR
Consulta® CRT-P, Syncra® CRT-P
EveraTM XT DR , Evera S DR, Protecta® XT DR, Protecta DR,
Secura® DR, Virtuoso® II DR, Maximo® II DR, Virtuoso DR
VivaTM XT CRT-D, Viva S CRT-D, Protecta XT CRT-D,
Protecta CRT-D, Consulta CRT-D, Concerto® II CRT-D,
Maximo II CRT-D, Concerto CRT-D
Sources: Medtronic Adapta®/Versa®/Sensia® Reference Guide; Medtronic Consulta® CRT-P Clinician Manual; Medtronic
Protecta XT DR Clinician Manual; Medtronic Protecta XT CRT-D Clinician Manual.
This document is provided for general educational purposes only and should not be considered the exclusive source for this
type of information. At all times, it is the professional responsibility of the practitioner to exercise independent clinical judgment in
a particular situation. Changes in a patient’s disease and/or medications may alter the efficacy of a device’s programmed
parameters or related features and results may vary. The device functionality and programming described in this document are
based on Medtronic products and can be referenced in the published device manuals.
© 2013 Medtronic, Inc.
Page 3 of 4
Indications, Safety, and Warnings
Brief Statement: IPGs, ICDs, CRT ICDs and CRT IPGs
Implantable pulse generators (IPGs) are indicated for rate adaptive pacing in patients who may benefit from increased pacing rates concurrent with
increases in activity and increases in activity and/or minute ventilation. Pacemakers are also indicated for dual chamber and atrial tracking modes in
patients who may benefit from maintenance of AV synchrony. Dual chamber modes are specifically indicated for treatment of conduction disorders that
require restoration of both rate and AV synchrony, which include various degrees of AV block to maintain the atrial contribution to cardiac output and VVI
intolerance (e.g. pacemaker syndrome) in the presence of persistent sinus rhythm. For the MR conditional IPGs, a complete pacing system consisting of a
Revo MRI or Advisa MRI IPG and 2 SureScan leads is required for use in the MR environment.
Implantable cardioverter defibrillators (ICDs) are indicated for ventricular antitachycardia pacing and ventricular defibrillation for automated treatment
of life-threatening ventricular arrhythmias.
Cardiac resynchronization therapy (CRT) ICDs are indicated for ventricular antitachycardia pacing and ventricular defibrillation for automated treatment
of life-threatening ventricular arrhythmias and for providing cardiac resynchronization therapy in heart failure patients who remain symptomatic despite
optimal medical therapy, and meet any of the following classifications:
New York Heart Association (NYHA) Functional Class III or IV and who have a left ventricular ejection fraction ≤ 35% and a prolonged QRS
Left bundle branch block (LBBB) with a QRS duration ≥ 130 ms, left ventricular ejection fraction ≤ 30%, and NYHA Functional Class II.
CRT IPGs are indicated for the reduction of the symptoms of moderate to severe heart failure (NYHA Functional Class III or IV) in those patients who
remain symptomatic despite stable, optimal medical therapy, and have a left ventricular ejection fraction less than or equal to 35% and a prolonged QRS
IPGs and CRT IPGs are contraindicated for dual chamber atrial pacing in patients with chronic refractory atrial tachyarrhythmias; asynchronous pacing in
the presence (or likelihood) of competitive paced and intrinsic rhythms; unipolar pacing for patients with an implanted cardioverter defibrillator because it
may cause unwanted delivery or inhibition of ICD therapy; and certain IPGs are contraindicated for use with epicardial leads and with abdominal
ICDs and CRT ICDs are contraindicated in patients whose ventricular tachyarrhythmias may have transient or reversible causes, patients with incessant
VT or VF, and for patients who have a unipolar pacemaker.
In CRT ICD systems, the leads are contraindicated for patients with coronary venous vasculature that is inadequate for lead placement, as indicated by
venogram. The lead is also contraindicated in patients for whom a single dose of 1.0 mg of dexamethasone acetate and/or dexamethasone sodium
phosphate may be contraindicated.
Changes in a patient’s disease and/or medications may alter the efficacy of the device’s programmed parameters. Patients should avoid sources of
magnetic and electromagnetic radiation to avoid possible underdetection, inappropriate sensing and/or therapy delivery, tissue damage, induction of an
arrhythmia, device electrical reset or device damage. Do not place transthoracic defibrillation paddles directly over the device. Additionally, for CRT ICDs,
certain programming and device operations may not provide cardiac resynchronization.
Potential Complications
Potential complications include, but are not limited to, rejection phenomena, erosion through the skin, muscle or nerve stimulation, oversensing, failure to
detect and/or terminate arrhythmia episodes, and surgical complications such as hematoma, infection, inflammation, and thrombosis. An additional
complication for ICDs and CRT ICDs is the acceleration of ventricular tachycardia.
See the device manual for detailed information regarding the implant procedure, indications, contraindications, warnings, precautions, and potential
complications/adverse events. For further information, please call Medtronic at 1-800-328-2518 and/or consult Medtronic’s website at
Caution: Federal law (USA) restricts these devices to sale by or on the order of a physician.
World Headquarters
Medtronic, Inc.
710 Medtronic Parkway
Minneapolis, MN 55432-5604
© 2013 Medtronic, Inc.
Tel: (763) 514-4000
Fax: (763) 514-4879
Toll-free: 1 (800) 328-2518
(24-hour technical support for physicians and medical professionals)
Page 4 of 4