This document discusses strategies to minimize right ventricular pacing, which can have deleterious effects. It summarizes several clinical trials that evaluated ventricular versus atrial or dual-chamber pacing. The trials generally found that atrial or dual-chamber pacing reduced atrial fibrillation compared to ventricular pacing, though effects on other outcomes like mortality were less clear. The document recommends that right ventricular pacing be avoided or minimized when possible, through use of AAI pacing, DDD pacing with long fixed AV delays, search AV hysteresis algorithms, or mode-switching algorithms that favor intrinsic conduction.

1. Right Ventricular Pacing Revisited
Unavoidable
or to be
Avoided
Alireza Ghorbani Sharif, MD
Electrophysiologist
Tehran Arrhythmia Center
March 2016

2. Deleterious Effects of RV Pacing?
Altered left ventricular electrical and
mechanical activation:
– Pacing-induced LV dyssynchrony secondary to the
abnormal activation sequence, ventricular dyssynchrony
may be present in up to 50% of the patients after long term
RV apical pacing
– Less work produced for given LVEDV
– Delayed papillary muscle activation → Valvular insufficiency
thus causing MR
ANTONIO DE SISTI, M.D., ePACE 2012; 35:1035–1043

3. Deleterious Effects of RV Pacing?
Remodeling
– Modified regional blood flow patterns
– Increased oxygen consumption without increase in blood flow
– Abnormal thickening of LV wall
Cellular disarray
– Fibrosis (away from pacing lead location)
– Fat deposition
– Calcification
– Mitochondrial abnormalities
25X: Karpawich PP, et al. Am Heart J 1990;119:1077-83

4. Abnormal Activation Sequence
In RV Apical Pacing

5. The amount of Pacing-induced LV dyssynchrony
is related to the presence of LV dysfunction at
Baseline
Laurens F. Tops, et al , JACC ,Vol. 54, No. 9, 2009

6. Pacing Mode Clinical Trials
DAVID Trial
JAMA 2002;288:3115-23
RV stimulation may be more deleterious in patients with
advanced LV dysfunction (ICD candidates); DDDR-70 was
worse than VVI-40; more pacing (60%) was seen in DDDR-
70; however, only 30.8% of the patients had a QRS>130ms
Danish Pacemaker Study
Andersen HR, et al. Lancet 1997;350:1210-16
AAI vs. VVI for SSS Danish pacemaker study: AAI had
slightly better survival and was associated with lower
occurrence of CHF (native AV conduction is better)
CTOPP Study
Patients undergoing first IPG implant, n=2,568 32
Canadian centers, Prospective, randomized
MOST Trial
Sweeney M, et al. PACE 2002;25:690
(mode selection trial in sinus-node dysfunction)
Hospitalization was not associated with mode but with
prevalence of more then 40% RV pacing
The PAVE Study
J. Cardiovascular, Electrophysiology 2005
Nov;16(11):1160-5 Left Ventricular-Based Cardiac
Stimulation Post AV Nodal Ablation Evaluation
MOST Sub-Study
There was a strong association between RV pacing and
risk of heart failure hospitalizations as well as
atrial fibrillation (AF) episodes

7. Danish Study
In the DANISH study, AAI was also associated with less Heart Failure and decreased mortality 4
4. Andersen HR, Nielsen JC, Thomsen PE, et al. Long-term follow-up of patients from a
randomised trial of atrial versus ventricular pacing for sick-sinus syndrome. Lancet.
1997;350:1210–6
5. Nielsen JC, Andersen HR, Thomsen PEB, et al. Heart Failure and Echocardiographic
Changes During Long-term Follow-up of Patients With Sick Sinus Syndrome Randomized to
Single-Chamber Atrial or Ventricular Pacing. Circulation 1998;97;987-995
45

8. Danish Study
Conclusions
In patients with SND, atrial pacing is associated
with a significantly higher survival, less atrial
fibrillation and less heart failure compared to
ventricular pacing.

9. CTOPP Study
Canadian Trial of Physiologic Pacing
Patients undergoing first
IPG implant
n=2,568
Ventricular-Based Pacing
n = 1,474
Physiologic Pacing
n = 1,094
Follow for an average of 3 years and compare:
•Stroke or death due to cardiovascular causes
•Death from any cause
•Atrial fibrillation
•Hospitalization for HF

10. CTOPP
Conclusions
Physiologic pacing (dual-chamber or atrial)
provides little benefit over ventricular pacing
for the prevention of stroke or death due to
cardiovascular causes.
Physiologic pacing does provide a reduction
in the relative risk of atrial fibrillation.

11. MOST Study
Mode Selection Trial in Sinus Node Dysfunction
Patients Undergoing Initial IPG
Implant for SND
n=2010
Dual-Chamber Pacing
n=1014
Ventricular Pacing
n=996
Follow for a median of 33 months and compare:
•Death from any cause or non fatal stroke
•Composite of death, stroke, or hospitalization for HF
•Atrial fibrillation
•Heart Failure score
•Pacemaker syndrome
•Quality of Life

12. MOST
Conclusions
In patients with SND, dual-chamber pacing reduces
newly diagnosed and chronic atrial fibrillation reduces
signs and symptoms of heart failure and slightly
improves quality of life.
Dual-chamber pacing did not improve the rate of the
primary endpoint of mortality or freedom from stroke.

13. DAVID Trial
Dual-Chamber and VVI Implantable Defibrillator Trial
760 assessed for eligibility
250 excluded
149 Did not meet Rx criteria
55 refused
46 Other
510 eligible
4 Not randomized
2 Required pacing
1 Inadequate defibrillation threshold
1 Decided not to implant
506 randomized
VVI-40 (n=256) DDDR-70 (n= 250)
• 1 had pacing mode set to DDD
• 1 LTF
• 10 Discontinued intervention
• 5 Bradycardia
• 1 CHF and AF
• 1 Brady induced Torsade
• 1 Heart Tx workup
• 1 AF w rapid V response
• 1 multiple shocks due to double counting
• 3 had pacing mode set to VVI
• 2 LTF
• 5 Discontinued intervention
• 1 Angina
• 1 CHF and Lead Failure
• 1 CHF Hospitalization
• 1 Exacerbation of VT
• 1 Lead Migration
Wilkoff B, et al. JAMA. 2002; 288: 3115-3123

14. DAVID
Conclusions
In ICD patients:
In Patients with intact conduction, RV pacing greater than 40%
leads to an increase in death and Heart Failure Hospitalization.3
3. Wilkoff BL, Cook JR, Epstein AE, et al. Dual-chamber pacing or ventricular backup pacing in patients with an implantable
defibrillator: the Dual Chamber and VVI Implantable Defibrillator (DAVID) Trial. JAMA. 2002;288:3115–23.

15. MOST Sub-studyMOST Sub-study
Conclusions: Heart Failure Hospitalization (HFH)Conclusions: Heart Failure Hospitalization (HFH)
• V-pacing is > 40%
- HFH risk is constant
• V-pacing is < 40%
-For each 10% reduction in V-pacing there is a 54% relative
reduction in risk for HFH
-2% when pacing was minimized to < 10%
Sweeney MO, et al. Circulation 2003
Risk
of HFH
Cumulative % Ventricular Pacing

16. Relationship between risk of AF and Cum%VP
was similar between pacing modes:
– Risk of AF showed a linearly increasing relationship
with increased Cum%VP from 0% pacing up to 80-
85% pacing in both pacing modes.
– The risk of AF increased by 1% for each 1%
increase in Cum%VP
MOST Sub-study
Conclusions: AF
Sweeney MO, et al. Circulation 2003, in press

17. Summary of Clinical Trials
MortalityMortality
HospitalizatiHospitalizati
on for CHFon for CHF
AtrialAtrial
FibrillationFibrillation StrokeStroke
Danish
AAIR vs. VVIR; All SNDAAIR vs. VVIR; All SND
ptspts
But notBut not
until afteruntil after
3 years FU3 years FU
Both acuteBoth acute
and chronicand chronic
NSNS
CTOPP
Physiologic vs.Physiologic vs.
ventricular pacing; ~40%ventricular pacing; ~40%
of pts had SNDof pts had SND
But not untilBut not until
2 years FU2 years FU
MOST
Dual-chamber vs. singleDual-chamber vs. single
chamber; All SND ptschamber; All SND pts
But stillBut still
10% at 3610% at 36
monthsmonths
But still 24-But still 24-
25% at 3625% at 36
monthsmonths
DAVID
No indication for pacingNo indication for pacing
(Composite(Composite
endpoint)endpoint)
NSNS NSNS
= No Difference ObservedNS = Not a studied endpoint

18. Right Ventricular Pacing
should be Avoided
or
to be Minimized

19. Strategies for reduction of RV
Pacing
1. Use of AAI pacing mode
2. DDD pacing with a fixed long AV delay
3. Search AV hysteresis
4. AAI(R)-DDD(R) mode switch Algorithms

20. AAI Pacing: Too Risky?AAI Pacing: Too Risky?
AAI pacing preserves a normal ventricular activation sequence
The incidence of progression to symptomatic AV block in SNDThe incidence of progression to symptomatic AV block in SND
patients been estimated at about 2% per yearpatients been estimated at about 2% per year
Supraventricular tachycardias can develop in as high as 50% ofSupraventricular tachycardias can develop in as high as 50% of
patients with SNDpatients with SND
AAI pacing is ineffectual for ventricular bradycardia during
– Paroxysmal and permanent AF
– AV block

21. Fixed Long AV Delays
Long AV delays may reduce unnecessary ventricular
pacing
The main disadvantage of a fixed long AV delay are:
– Total atrial refractory period (TARP) is prolonged, leading to
exercise-induced AV block
– Post-ventricular atrial refractory period (PVARP) is shortened to
compensate and it can predispose to pacemaker-mediated
tachycardia (PMT)
– Abandonment of mode-switching or significantly delayed AF
recognition

22. • Automatically adjusts AV delay so that:
AV Delay > Patient’s intrinsic PR interval
Preserves normal ventricular depolarization if
intrinsic conduction exists
Optimal AV delay when V pacing required
Search AV Hysteresis Algorithms
to reduce unnecessary RV Pacing

23. AV Search Hysteresis
Algorithm
• Searches for intrinsic conduction by prolonging the AV delay interval
regularly every five minutes
• If intrinsic ventricular activity is found during the extended AV delay,
the pacemaker adjusts the AV delay settings (paced and sensed) to
accommodate this intrinsic activity
• If no more intrinsic ventricular is sensed, the AV delays resume their
previously programmed values
• Do not allow non-conducted beat

24. DDD with and without AV Search
does not eliminate RV Pacing in many patients
% of patients with %VP ≥ 20%
25%
69%
23%
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
DDD w fixed AV
Delay=300ms
AV Search
Hysteresis -
INTRINSIC RV Pre
Amendment
AV Search
Hysteresis -
INTRINSIC RV Post
Amendment
6. Nielsen JC, Pedersen AK, Mortensen PT, Andersen HR. Programming a fixed long atrioventricular delay is not effective in preventing ventricular pacing in patients with sick sinus syndrome. Europace.
1999;1:113–20.
7. Olshansky B et al. Reduction of Right Ventricular Pacing in Patients with Dual-Chamber ICDs. PACE 2006; 29:237–243
•AVSH parameters were modified under a protocol amendment. Rate hysteresis was set at a 20bpm offset, which allowed the lower rate limit
to approach 40bpm with intrinsic conduction. AVSH AV increase was changed from 50% to 100% pacing.
6
7*
7*

25. AAI(R)-DDD(R) mode switch Algorithms
Managed Ventricular Pacing (MVP) algorithm by
Medtronic
SafeR algorithm by Sorin
RYTHMIQ algorithm by Boston Scientific
Vp Suppression algorithm by Biotronik
Colin Cunnington ,University Hospital of South Manchester

26. Managed ventricular pacing or MVP modes can be used in all
patients, but are most effective in SND patients with reliable
AV conduction and normal ventricular activation.
Unnecessary RV pacing can be reduced down to less thanUnnecessary RV pacing can be reduced down to less than
10%.10%.
Pacemaker can switch from AAI(R) to DDD(R) backPacemaker can switch from AAI(R) to DDD(R) back
depending on AV conduction.depending on AV conduction.
Managed Ventricular Pacing
(MVP) Algorithm

27. Managed Ventricular Pacing
(MVP) Algorithm
AAI(R) mode and mode-switches to DDD(R)or DDI(R) in case of
conduction loss or AT/AF episodes
Detection Uses 4 of 7 Mode
Switch Detection Criteria Conduction Check Failed
Increment Check Interval
(1, 2, 4, 8 mins up to 16 hrs)
DDIR
Loss of
Conduction
AV
Conduction
Check
AT/AF Episode
AAI(R)
DDD(R)
One
Cycle
AAI(R)
Initialize
Conduction Check Passed
AT/AF
Terminates

28. 73.8
4.1
48.7 47.3
0
20
60
80
100
% Pacing
40
Mean %VP Mean %AP
DDD/R MVP
Sweeney MO et al. Heart Rhythm 2004;1:160-167
Sweeney MO et al. J Cardiovasc Electrophysiol 2005;16:1-7
MVP Study Results: Reduction in
%VP without Loss of Atrial
Support

29. 1065 SND patients randomized – DDDR pacing versus DDDR Minimal
Ventricular Pacing
The Save Pace TrialThe Save Pace Trial
(Search AV Extension and Managed Ventricular Pacing for
Promoting Atrioventricular Conduction)

30. AV Synchrony
Restored
Loss of AV
Synchrony
RYTHMIQ operates in AAI(R) pacing mode with VVI
backup during times of normal conduction, switching
to DDD(R) mode when a conduction block is detected
RYTHMIQ Algorithm

31. Options should be considered
in patients with chronic
RV apical Pacing
1. Alternative RV pacing sites
2. Upgrade of RV apical pacing to CRT

32. Alternative Pacing Sites
RV septal pacing sites are the most studied
alternative RV sites for pacing.
Recent clinical studies have suggested that
RV septal pacing can potentially prevent the
long-term adverse effects associated with RV
apical pacing.
HUNG-FAT TSE, M.D,et al J Cardiovasc Electrophysiol, Vol. 20, pp. 901-905, August 2009

33. Shortest distance to Purkinje Fibers?
Right Ventricular Outflow Tract (RVOT) and/or Right Ventricular Septum

34. Alternative Pacing Sites
LV dysfunction induced by iatrogenic abnormalLV dysfunction induced by iatrogenic abnormal
ventricular electrical activation related to RV apicalventricular electrical activation related to RV apical
pacing is still reversible by upgrading RV septalpacing is still reversible by upgrading RV septal
pacing even after a mean of 13 years of pacing.pacing even after a mean of 13 years of pacing.
HUNG-FAT TSE, M.D,et al J Cardiovasc Electrophysiol, Vol. 20, pp. 901-905, August 2009

35. Alternative Pacing Sites
In patients with permanent RV apical pacing andIn patients with permanent RV apical pacing and
preserved LVEF in whom ventricular leadpreserved LVEF in whom ventricular lead
replacement is required, RV septal pacing is areplacement is required, RV septal pacing is a
feasible option to improve LV function and exercisefeasible option to improve LV function and exercise
capacity.capacity.
It remains unclear whether RV septal pacingIt remains unclear whether RV septal pacing
upgrading can be used to treat patients with RVupgrading can be used to treat patients with RV
apical pacing induced heart failure.apical pacing induced heart failure.
HUNG-FAT TSE, M.D,et al J Cardiovasc Electrophysiol, Vol. 20, pp. 901-905, August 2009

36. RV septal Pacing upgrading
HUNG-FAT TSE, M.D, J Cardiovascular Electrophysiology, Vol. 20, pp. 901-905, August 2009

37. Upgrade of RV apical Pacing to CRT
For patients with conventional pacemaker whoFor patients with conventional pacemaker who
developed heart failure, upgrade to CRT should bedeveloped heart failure, upgrade to CRT should be
considered.considered.
LV reverse remodeling after upgrade from RV apicalLV reverse remodeling after upgrade from RV apical
pacing to CRT has been demonstrated and severity ofpacing to CRT has been demonstrated and severity of
MR may improve.MR may improve.
Laurens F. Tops, et al , JACC ,Vol. 54, No. 9, 2009
2013 ESC Guidelines, Europace (2013) 15, 1070–1118

38. Upgrade of RV apical Pacing to CRT
Laurens F. Tops, et al , JACC ,Vol. 54, No. 9, 2009

39. Conclusions
RV pacing increases the risk for HF, AF and death
AAI is superior to VVI and DDD for patients with
intact conduction
Novel pacing algorithms have shown to reduce
unnecessary RV pacing by 99% in pacemaker and
ICD patients
Selective pacing site appears promising
Upgrade to CRT in heart failure patients should beUpgrade to CRT in heart failure patients should be
consideredconsidered