Studies proving the deleterious effect of RV pacing:
1. Wilkoff, Bruce and The DAVID Trial Investigators. Dual-Chamber Pacing or Ventricular Backup Paciing in Patients with an
Implantable Defibrillator: The Dual Chamber and VVI Implantable Defibrillator (DAVID) Trial. JAMA. 2002; 288: 3115-3123.
2. MOST - Lamas, Gervasio, et. All. Ventricular Pacing or Dual-Chamber Pacing for Sinus-Node Dysfunction. N Engl J Med 2002; 346: 1854-62:
INTRINSIC RV demonstrated that if RV pacing got to 0, there was a higher % of death than with some patient.
Max AVD: BOS 400 ms, SJM 450 ms, MVP infinity
Sensed AV offset / reverse hysteresis - decrease AVD - increase refractory sensing - pace with a shorter AVD
AV search hysteresis: prolong by 30 msecs every 36 beats (changeable parameters)
Stability: if AF shocked only.
Limits: SVT 260 ms, VF 320 ms, VT 360 ms
MDT: when you put a magnet on device and you hear a siren like alert => shock was delivered since last interrogation
VVIR mode (BIV PPM) will not show you % VP. You can look at it on VS episodes and cardiac compass
Exercise setup: if the patient gets tired with minimal walking=> increase ADL response (less inputs to reach ADL HR) and increase ADL to
higher HR. If you manually increase the rate set point optimization rate turns off automatically.
During exrecise Current Values
Mode VVIR VVIR
lower rate 70 70
ADL rate 95 95
Upper sensor rate 130 130
Upper tracking rate 130 130
Optimization On On
ADL rate setpoint 7 5
Upper sensor rate setpoint 19 19
Primary prevention programming in a patient with NSVT/AF:
Mode switch AAI <=> DDD. No forced AVD. This way you avoid pacing the V unnecessarily.
MDT: MVP happens when it counts >2As for 1 V for 3 consecutive runs.
Program 200 in the VF zone if a person is young, 188 if old.
ATP: 240 is limit.
VT 167. Run of 40 VT prior to administering therapy. 8 Pulses, 84%, smart mode on.
A= Can, B= RV tip, X= SVC. Program AX>B x4, 4th is BX>A x1 then AX>B.
Monitor zone is 44 consecutive beats. Set at 140 bpm. Has to be higher than VT.
RV sensitivity was lowered to 0.3 mV for MDT - 0.6 SJM - 0.5 for Boston
1:1 SVT is turned off immediately after implant - cause if a lead dislodges it would not treat (1:1 discrimination). Wait 6-8 weeks then turn it on
Home monitor: on
Alert enable: on (if 1 shock is delivered)
EGM recorded is wavelet
Prearrhythmic ECG: off (saves battery)
Michael Gold did a study comparing SC vs DC ICD discrimination factors and found no difference
To program initial AVD in BiV Pacing - Gold's formula:
SAVD = 0.7 x PRI - PAVD = SAVD + 30
PAVD = 0.7 x PRI
If PRI > 150 ms don't add anything
If PRI < 150 ms add 30 ms to formula above
Gold's formula for calculating the PAVD: if PRI = 200 ms => SAVD. Add 40 usually and that's your PAVD. If QRS > 150 ms then substract 30 ms
off the PAVD however not if too short an interval
PAVD (gold's formula) = PRI x 0.7, if QRS is > 150 ms then substract 30 ms unless it's too short
SAVD = PAVD - 30
Optsite study: Compared in AF patients who had AVN ablation RV pacing vs BiV pacing. Both did well short term however on the long run BiV did
BIV: Post BiV implant the patient had dificulty tracking the atrium based on a marked prolonged AV interval in combination with oversensing the T
wave during pacing which produced recurrent atrial retrograde sensing with loss of BiV pacing. This was corrected with placing atrial tracking
recovery with a shortened minimum PVARP and decreasing ventricular sensitivity to 0.9 mv.
Trying to obtain A threshold by AAI pacing not working, when lookingat the channels you see AS- VS - (AS). when looking at A lead younotice far-
field R wave sensing. Which is why the device does not paceat the set speed when trying to get threshold, for it's seeing doublethe number of A
waves. You look at sensitivity and notice it's set at0.2 which is pretty high. You measure the P waves (sensing) and seethey measure 2, you then
decrease sensitivity to 0.75 (from 0.2 - 0.75being the third of the measured P wave) and notice the device is nowreading only P waves and not
far field oversensing anymore.
Generator change in CHB: either do the lead switch quickly or you could put the red clamp on the wheatlander and the blackclamp on the tip and
this switches the device to unipolar pacing
Mode switches / AVD for all companies:
happens when it counts >2 As for 1 V for 3 consecutive runs.
The 2 dropped beat method: AS - VS - AS 1st..................AS 2nd(80 ms) nothing happens => VP beat and mode switches AAI => DDD.And the
mode switch occurs if this happens in 2 consecutive beats out of 4
Device will mode switch if it waits for offset + X and nothing happens. If SAVD = 200 and PAVD = 200, offset + X = 450 ms
-Set monitoring parameters with PMT monitoring turned on low priority (a few episodes will be recorded)
-Turned VIP on extending AVD every 30 seconds by 200 ms for 3 cycles to detect conduction and minimize V -pacing . Also extended PAVD and
SAVD to 225 and 200 ms allowing a maximum of 425 search window when doing VIP testing
-Boston Search Hysteresis
SAV = 200, PAVD = 200, offset is 200 +200 = 400 ms
When programming mode switch do not change upper rate (180 bpm) unless you have slow AT. And always lower the lower rate from 80 to 65
otherwise the patient will be paced all the time. Another advantage of 65 is when called you will know if the patient is paced at 65 all the time they
mode switched and not in CHB (cannot see underlying AF on ECG)
TARP = SAVD + PVARP
If PRI is increased and TARP increases you will end up dropping the URL ofpacing by going to 2:1 AVB or wenckebach
Always set sensitivity to 0.3 (not nominal) cause at the time of implantthe sensitivity is set high to try to sense all events.
R waves are always smaller after implant because of filter turned on
T wave oversensing -
Check if R waves dropped in amplitude. Episodes occurred mostly cause of low R wave amplitude not T waves got bigger
Check CXR (PA) shows no change in RV lead positioning
DFT done at implant at 1.2 mV successful
Sensing R waves in different configurations: polarity Tip to Can : 7.9 mV - Tip to Ring 4.3 mV
Change polarity: to Tip to Can since R waves were better sensed with this polarity
Change sensitivity from 0.3 to 0.45 (Measured T waves were 0.4 during episode unfortunately there was no T wave oversensing during
Check implant DFT was tested at 1.2
Get a PA/lat CXR.
Turn off Dynamic PVARP in SJM
ATP for TWOS with iatrogenic VT, resulting in maximum output shock. Oneadditional shock for TWOS alone. Large, biphasic, qualitatively
ischemic Twaves during episode.
RV sensitivity reduced to 0.6 mV and reprogrammed integrated bipolar configuration.
Recommendations for high DFTs
System revision - Possibilities include the following:
1. Tripolar SQ array +/- system extraction (to enhance surfact area)
2. Changing internal coupling of the SQ lead
3. Change of the system to a totally subcutaneous ICD system
Monitor: 4 for 4/4 -> 4 for 0/12 - 4 allocations (4 recorded EGMs). AEGM instead of VEGM. Don't turn on pre=> wastes battery
-Tachy programming: 200 in the VF zone if a person is young, 188 if old.
ATP: 240 is limit. VF 188 - VT 167. Run of 40 VT prior to administering therapy. 8 Pulses, 84%, smart mode on.
-A= Can, B= RV tip, X= SVC. Program AX>B x4, 4th is BX>A x1 then AX>B.
-Monitor zone is 44 consecutive beats. Set at 140 bpm. Has to be higher than VT.
-1:1 SVT is turned off immediately after implant - cause if a lead dislodges it would not treat (1:1 discrimination). Wait 6-8 weeks then turn it on
- Home monitor: on
-Alert enable: on (if 1 shock is delivered)
-EGM recorded is wavelet
-Prearrhythmic ECG: off (saves battery)
BiV ICD programming - MDT - ANdriulli
VF 200 bpm (300 ms) 6 shocks 35 J B>AX (RV coil to can) with 5th shock reversed (AX>B) 30/40
VT 167 bpm (360 ms) therapy ATP 8 pulses, 3 bursts, 84% 40 to allow for NSVT monitoring in a patient known to have VT
VT monitor 133 bpm (450 ms) count of 44
VT vs SVT: stability off (no known AF), onset off, 1:1 SVTs off (always off after implant cause if a lead dislodges it would not treat, could turn on
in 2 weeks), wavelets on 70%, T wave on, RV lead noise On with time out nominal is 0.75 min meaning if noise on lead > 0.75 min therapy will be
SVT discriminators Upper Limit 260 ms (meaning if above 260 ms all SVT discriminators will be turned off and therapy will be delivered cause it
has been shown that ATP therapy at CL < 260 ms are not efficient)
Smart Mode: On
AT/AF monitor 350 ms (171 bpm)
Programmed 60 -130 (patient with no SSS or conduction disease)
V pace polarity:
LV Ring to RV Coil
LV Tip to RV Coil (Unipolar)
RV Tip to RV Ring (Bipolar)
DF4 : Ring => SVC => RV coil => Tip
Revo PPM has built in VT/SVT discrimination parameters that you cannot change
SVT was read as VT because the baseline R-R interval wobbled
Protecta: RV lead far/near comparison. Partial +
TARP = SAVD + PVARP
When TARP increases your URL decreases
MDT has noise algorithm for Riata leads as well. It has a timeout and John increases it to 2 min (nominal 0.45 min) because they have seen a lot
ofpatients being shocked wrongfully
Partial + resolves far-field on A. Increases decay and increases upper limit
MDT is the only firm that allows discriminators on in the VF zone. So we setup a low VF zone 188 bpm and turn discriminators such as rate
timeout onas well as waveform (70%). If patient has no history of VT - no VT zonewill be programmed except for monitoring. For other devices
you have tofool the device and program a VF zone at 222, at VT therapy zone 188-222with discriminators and VT monitor zone lower.
MDT also has a discriminator that comes in the VF zone called PR logic -In order to maintain BiV Pacing MDT has programmable AVD that
extends andshortens based on the HR
MDT has sense assure which will decrease autocapture once at 1 AM (n) or asset everyday in order to save battery, then it will schedule a 2x
safe zoneof output pacing. The minimum it will go down to is 1.5. It does not skip abeat but how it detects for loss of capture is by detecting loss
ofelectrovoltage activation (alignerment of cations and ions at the bipolarlead tip)
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.
How atrial tachyarrhythmia is detected
When the A–A rate exceeds the Detect Rate and is sustained for the Detect Duration, the pacemaker assumes that atrial tachyarrhythmia is in
In monitoring for rapid atrial rates, the pacemaker monitors for rapid consecutive A–A intervals. If the Blanked Flutter Search parameter is On,
the pacemaker also monitors for A–A intervals that may indicate 2:1 blanking of atrial events.
The pacemaker first monitors for any four of the last seven consecutive A–A intervals that are shorter than the detect rate interval. These include
all A–A intervals except AS–AP and AR–AP intervals and AP–AR–AP sequences, which are classified as far-field R waves.
If no rapid A–A intervals are detected (as described in Step 1) and Blanked Flutter Search is On, the pacemaker next monitors for eight
consecutive A–A intervals
– that are less than twice the total atrial blanking period (which is the SAV + PVAB) and
– where one half of the A–A interval is less than the detect rate interval
If these criteria are met, the pacemaker will extend PVARP to 400 ms to uncover any blanked AS events. If an AR event is sensed, 2:1 sensing of
an atrial tachyarrhythmia is assumed. If no AR event is sensed, the pacemaker resumes monitoring for 2:1 sensing of atrial tachyarrhythmias in
Once rapid consecutive A–A intervals are detected or 2:1 blanking of atrial events is detected, the Detect Duration delay timer is started. The
pacemaker will not mode switch until this timer expires.
To meet the Detect Duration delay, the pacemaker monitors that every eighth A–A interval is less than the detect rate interval. Once the Detect
Duration timer expires, the pacemaker mode switches.
SAV = 200, PAVD = 200, offset is 200 +200 = 400 ms
Hysteresis: it will drop the lower rate to 15 less then LRL in order to allow intrinsic pacing as much as possible
Atrial Tach Response: if reaches tach upper limit of mode switch at 170 (ie A flutter) it will reset the blanking period everytime it reaches that limit
in order not ot pace the ventricle fast
BOS Ingenio PPM (with tele capability/home monitoring)
It has the longest AVD on the market (400 ms)
Minute Ventilation blended sensor: transthoracic accelerometer. Also a respiratory sensor, if RR increases HR increases, measured against
Autocapture in V (0.5 above is safety margin) once every 21 hours
Standard sensing, same as ICD< if AF it auto adjusts.
It has the same battery as ICDs, 7+ lifetime if everything is turned on (AP 20%, VP 75%)
Has Rhythmik: it will switch from DDD to AAIR for 3 beats and VP backup at 45 bpm (15less than LRL). If it VP 3 x then it will switch back to DDD.
This is to allow normal ventricular activation. Mode switch is AAIR -> VVI backup 70 @ 170 (nominal) for 30 secs
Best battery out there is Biotronik
BOS Incepta 41 J - Rhythm ID 945. If he has an event interrogate and readjust % morphology
Sustained Rate Therapy: duration 3' nominal. Watch for 3', and if witholding therapy even if SVT it will deliver therapy regardless. Turned off.
BOS Hysteresis do not go as low as 40 where patient will become symptomatic.Most people do not program hysteresis anymore. Nominal is 50
bpm, every 1or 5 minutes, for 3 cycles.
SJM Pacemakers: Accent < Victory < Zephyr
Zephyr recorded episodes and drained the battery real fast (3 years). This has been fixed with Accent where you can turn episode recording
Stored EGM is I
High V rate trigger off (if watching AF and SVT not VT)
Turn on monitor alert for V impedance
SJM Ellipse (old ICD was Epic)
-Autocapture: Q 8 hours or Q 24 hours (adjustable) check off thresholds and sets it 0.5 mV above threshold
-Secure sensing: Noise algorithm from RV can to RV coil. If it detects noise (near-field, far-field) it witholds therapy -> good for Riata leads.
Cause VF should be on both channels and not only one
-Elliptical in shape
-ATP recharging algorithm
SJM ellipse goes 30-36 J
Fortify goes 36-40 J
No VF detection zone available on SJM. VT-2 zone created 169-189 with 1x ATP (88%) followed by shocks with detection on.
SJM detection : morphology (60%, 70% is MDT), stability, onset: if all and V-A (if difference between A-V and V-A > 60 ms on more than 4 beats
then it falls within SVT detection (retrograde A conduction)
SJM counts VF if average of 3 beats in a 4 beat count fits criteria for VF then count is 1, then it adds up to 16 beats in order to deliver therapy
MDT count is a running absolute count
This is a feature on old SJM devices and when doing agenerator change once taken out of the pocket the device stops pacing. Oncethe device
goes out of safe mode to regular programming there needs to be adumping of memory which may take 3-4 min. When using Bovi use in
shortbursts and not continuous otherwise you might initiate safe mode especiallyif you use Bovi on the can. The reason why safe mode picks
unipolar pacingis because it picks the central lead which it assumes is the safest byposition and so it goes unipolar.
SJM ellipse -special features: 450 ms AVD longest amongst its peers. Secure sense andstores (only device that does that) signals if it detects
noise and farfield does not correlate to near field it calls it noise and witholdstherapy. MDT has a similar feature but it does not store these EGMs.
-T wave oversensing in SJM
T waves were tall and device was double counting.To avoid that you can extend the PVARP but then if the patient is tachycardic the P waves will
fall in the PVARP which will decrease BiVpacing. You can also decrease sensing to a max of 1.2 to not overcount Ts.Need to check DFTs after
these changesSJM has a 2 phase decay to not overcount tall T waves which you can adjustboth plateau and decay. Turn dynamic PVARP off
SJM have Quickopt for optimizing BIV pacing -Aim for 98-99% BiV pacing.Published study found a difference at > 92%
SJM have Fusion. LV paces when detects RV impulse however it aint good
Discrimination factors: If all/none => SJM only
SJM Unify Assura (CRT)
-CRT Quickopt toolkit: automaticalyl finds best AVD
-Autocapture and autosense A/V
-AMS: DDIR 170->80
-LV Quad lead which has 10 vectors (i.e. mid 3 to RV coil)
-Noise discrimination algorithm: secure sense (farfield and nearfield)
Biotronik Evia and Evia HF-T PPM
-Cap control feature: Off => ATM: monitors thresholds only and sends info via telephone line
-Cap control feature: On => adjusts threshold starting at 3.6 V and decreasing by 0.6 until capture is lost. It's not advised to turn it on initially
because of the inflammatory changes at the lead tissue interface it will keep resetting the threshold with high variability. Recommended to turn it
on after 1 month
-Dynamic AVD: nominal settings 150-180
-Safe Mode: It goes in DDI - 70 / 7.5 V / 1.5 msec / unipolar when it senses prolonged noise or high EMI. When it goes unipolar configuration: tip
to can and if the device is out of the pocket then it cannot pace. A rapid fix is to put the device back in the pocket quickly if the patient is pacer
-Evia has Optiovol features which on the ICD monitors 1042 measurements Q 24 hours. It also measures patient activity, HRV and V avg rate and
V avg rate at rest
-MVP = V pace suppression RV pacing. Once A rate > 160 then it goes in mode switch. A rate has to be > 160 (nominal but can be changed) 5/8
beats to go in and 5/8 beats to go out. Fall back VVI pacing rate = LRL + 10 (can be changed + 20, 30 ...)
-Modes in Evia: DDD-ADI, DDD-ADIR, called the suppression modes
-DDD-CLS: is a closed loop stimulation, which is Bio's version of rate control. It measures the contractility of the myocardium and dictates how
fast the device goes based on that
-Evia has 6 configurations for LV pacing:
True Bipolar (LV tip to LV ring)
Common Ring Bipolar (LV tip to RV ring)
Inverse (LV ring to LV tip)
Ring to Ring bipolar (LV ring to RV ring)
Tip to Can unipolar (LV tip to case)
Ring to Can unipolar (LV ring to Can)
-36/48 AF events -> counts towards AF burden, this way it is harder to fill that counter and it avoids far field oversensing (which happen Q 5th
beat and will never fill that counter)
-Rate Trend counter last 24 hours is a feature you can interrogate and will give you a quick look of the last 24 hours including events, % pacing,
Biotronik Lumax ICD - Has a hysteresis function that you set the upper rate limit of, say you set AVD 350 ms, it will extend to 450 ms every 180
pacedbeats to try to detect normal AV conduction, if it misses it converts back to set AVD (S AVD 235 - P AVD 245). Also has mode switch
160/DDI - also has 60-130 > 130 it goes in 2:1 tracking. And has dynamic AVD.
MDT- rolling average (BIOT as well). Allows more irregular episodes=> program 30/40 unless history of syncope then nominal 16/24
SJM-box of 4, compare 3 to the 4th => this one you should program 12/16 count for VT
VVI: demand pacing 1200
ms timeclock. VRP
designed to prevent
unfavorable resetting of
device due to events like
afterdepolarizations or T
AAI: after PVC
no lead in V.
Will still pace
in the A
PPM WB - 2:1 no WB, program PPM WB by either shortening the PVARP or slow the MTR
If a P wave falls in interval 2 it will be sensed by the device and will be acted upon however it has to wait cause the device does not allow
pacing within the Maximum tracking rate 120 bpm before the V is paced, you will have PPM WB with progressive prolongation of the AV interval
before the dropped beat. It's advantageous to program the device with discrepancy between the TARP and MTR because if they are equal or
close to each other the device will track the P wave without any delay in AVD upto the end of TARP and then it will go in a 2:1 relationship
abruptly which is unfavorable for exercise symptoms of patient.
PMT results from a PVC associated with V-A conduction retrograde P wave falling outside of the PVARP sensed by the device and tracks it
near or at the UR of the device. Boards may ask strategies to prolong PVARP such as the retrograde P falls in that time interval is useful for
terminating PMT or preventing in first place.
DDD, ventricular failure to capture
Atrial failure to capture. u can see distortion of QRS by P.
sensing of P and V pacing 3rd complex. A sensing is
preserved and AP is lost
DDD, ventricular output failure - You don't see pacing
spikes, so no energy delivered this is not failure to
capture but failure of output
Ventricular over and undersensing
VVI 70 - 860 ms. Early pacing that seems to ignore the second QRS
= undersensing. You don't get pacing until 900 ms after the first
paced QRS and then 1040 ms so there's Oversensing of noise from
somewhere that's resetting the timeclock causing failure of output
this time related to oversensing.
If A oversensing occurs in a DDD system we will not get inhibition
but triggering of V pacing. Rapid V pacing during the interval of
A undersensing. P synchronous pacing in the beginning and atrial
event not acted on by device, and the device paces DDD instead.
strip with VT.
Paced at VVI and compared morphology perfect match
Starts with a PVC. VA conduction evident. Ends with a P that falls within PVARP
Paced with the A output set below threshold. PMT easily inducible will loss of A
Stopped PMT by increasing PVARP
The device didn't intervene because the PMT was ~100 bpm and PMT rate was 105 bpm
-If a PPM is set at VVI 60 and has no pacing longer periods > 60, possibly ventricular oversensing
-If patient has noise on both channels A and V when doing manual work, check header connections
-If you have diaphragmatic sensing related to valsalva you will get noise on the V lead and dizzy spells with bowel movements. Rx: extract and
replace ICD lead
-If ventricular oversensing the atrial beat as VS and not pacing patient has no safety pacing programmed cause old GUIDANT device, activate
safety pacing (80-110 ms) or change sensitivity of V channel in order not to sense A, or change post atrial blanking period (usually it is set at