Transcript Pacing Modes * Evidence review

Dr. Shreetal Rajan Nair
SR, Department of Cardiology
Introduction
 Aims of pacing
- Try to normalize cardiac output – heart rate and
myocardial contractility
- Achieve chronotropic competence, AV and
interventricular synchrony
- Bring comorbidities associated with pacing to a
minimum
- Improve exercise tolerance and quality of life.
What are the options available ?
 Single chamber – atrial , ventricular
 Dual chamber
 Fixed rate vs rate adaptive
Physiologic pacing ?
Includes atrial as well as dual chamber pacing
Indications
 SND
 A V conduction block
 Other indications
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Neurocardiogenic syncope
Carotid Hypersensitivity Syndrome
HCM
Long QTS
Pacing in SND
 SND is the most common indication for pacing.
 Patients with SND prone to develop AF and AV block
 AV block in SND
- 20% at the time of diagnosis
- 3- 35% in pacemaker implanted patients during 5 year
follow up
 AF in SND
- 40 – 70% at the time of diagnosis
- 3.9 – 22.3% during follow up
in pacemaker implanted patients incidence of AF
influenced by pacing mode, duration of ventricular
pacing and follow up duration
Pacing modes in SND
 Single chamber –AAI vs VVI
 Single vs dual - VVI vs DDD
Evidence review
 Major randomized trials
Danish study – SSS
PASE (Pacemaker Selection in the Elderly) – SSS + AVB
MOST (Mode Selection Trial ) - SSS
CTOPP (Canadian Trial of Physiologic Pacing ) - SSS +
AVB
5. DANPACE (The Danish Multicenter Randomized Study
on Atrial Inhibited Versus Dual-Chamber Pacing in Sick
Sinus Syndrome)– SSS
6. UKPACE (United Kingdom Pacing and Cardiovascular
Events)- AVB
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4.
HRS/ACCF expert consensus statement on pacemaker device and mode
selection. J Am Coll Cardiol 2012;60:682–703
HRS/ACCF expert consensus statement on pacemaker device and mode
selection. J Am CollCardiol 2012;60:682–703
Endpoints studied
 All cause mortality
 AF
 Stroke
 Heart failure
 Quality of life
 Pacemaker syndrome
AF
 Significant decrease in AF incidence in Danish,
CTOPP and MOST with relative risk reduction of 46%,
18% and 21% respectively.
 Supported dual chamber and atrial pacing
Stroke or thromboembolism
 Danish study showed a 57% risk reduction with atrial
based pacing
 Metaanalysis also showed a trend in favour of atrial
based and dual chamber pacing modes
 This effect may be due to less incidence of AF as
already described
Heart failure
 Danish study : atrial pacing improved heart failure
status
 MOST : 10% in DDDR group vs 12.3% in VVIR group
 Other studies failed to show a benefit for atrial
based pacing
Quality of life and functional status
 CTOPP : overall there was no significant effect of
pacing mode on quality of life
subgroup analysis showed improved quality of life in
those with high degree of pacing
 MOST and PASE showed definite benefit of dual
chamber pacing on quality of life
Pacemaker syndrome
 Symptoms of PACEMAKER SYNDROME was found to
be more in ventricular only pacing vs DDDR or AAIR
 improvement in quality of life reported earlier believed
to be lower incidence of pacemaker syndrome
Overall mortality
 Only the Danish study showed a benefit in favour of
atrial based and dual chamber pacing
Other studies and metaanalysis failed to prove any
definite advantage for atrial or dual chamber pacing.
The effect of RV pacing
 RV pacing associated with RV dysfunction and
interventricular dyssynchrony due to abnormal non
physiologic activation sequence.
 DDDR pacing associated with more dyssynchrony and
decrease in EF when compared with AAIR pacing
 MOST : increased incidence of HF and AF in DDDR vs
AAIR
Effect of RV pacing
 When compared with normal LV function vs LV
dysfunction , those with normal LV function fared
better.
Factors influencing patient outcomes :
1. LV function
2. Degree of RV pacing
3. Presence of structural heart disease
Managed ventricular pacing (MVP)
 Long-term RV pacing causes a deterioration of LV function through
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complex effects on regional ventricular wall strain and loading
conditions
MVP searches for intrinsic conduction and avoid unnecessary
ventricular pacing
Pacemakers can switch pacing mode from AAI(R) to DDD(R) in the
Managed Ventricular Pacing (MVP) mode
The MVP mode provides functional AAI(R) pacing with the safety of
dual-chamber ventricular support in the presence of transient or
persistent loss of conduction
The criterion to switch to backup ventricular pacing is loss of AV
conduction for two of the last four pacing cycles (the four most recent
A-A intervals
SAVE – PACe trial
Results
 Minimal Vpacing algorithms showed decrease in AF
burden and progression to permanent AF.
Single chamber atrial pacing vs
dual chamber pacing
 DANPACE: DDDR better in SND than AAIR only
pacing - this finding was in contrary to the earlier
studies – explanation was minimal ventricular pacing
protocols were used in the DDDR group in DANPACE.
 Very short and very prolonged AV intervals : increased
AF burden on follow up.
 DANPACE used moderately prolonged AV interval
protocols which resulted in less AF burden
Single chamber ventricular pacing
vs dual chamber pacing
 No trial showed any significant benefit of dual over
ventricular pacing
 Back up VVI pacing preferred in those not requiring
frequent pacing
 VVI pacing preferred in those with permanent and
long standing persistent AF
Rate adaptive pacing
 Indicated only for symptomatic chronotropic
incompetence
 No significant effect on quality of life or exercise time
though peak exercise heart rate increased
 Increased frequency of heart failure, AF noted in dual
chamber rate adaptive pacing vs those without
Circulation 2006;114:11-17
Circulation 2006;114:11-17
Endpoint assessment – all cause mortality
Healey et al Randomized Trials of Pacing Mode: A Meta-Analysis; Circulation. 2006;114:11-17
Endpoint assessment – AF
Healey et al Randomized Trials of Pacing Mode: A Meta-Analysis; Circulation. 2006;114:11-17
Endpoint assessment – STROKE
Healey et al Randomized Trials of Pacing Mode: A Meta-Analysis; Circulation. 2006;114:11-17
Pacing and mode selection in SND
AV BLOCK
AV conduction disease
 Intermittent AV conduction abnormalities progress to
complete heart block on long term follow up
 The minimum requirement is to prevent symptomatic
bradycardia
 The aim of pacing to establish AV synchrony without
affecting ventricular synchrony
 If there is no sinus node dysfunction then VDD mode
will maintain AV synchrony and chronotropic
competence
Why AV synchrony is essential
 Positive effect on cardiac output
 Increases stroke volume by 50% and decrease LAP by
25%
 AV synchrony also helpful in diastolic dysfunction
Three randomized trials
 PASE
 UKPACE
 CTOPP
compared single vs dual chamber pacing
in AV conduction disease
3 randomized trials
 Mostly elderly ( 73-80 yrs )
 CTOPP and PASE had both patients with sinus node
and AV conduction disease.
 AV block as primary indication of pacing : 49% in
PASE and 51% in CTOPP
 UK PACE had patients with AV conduction disease
only
UKPACE 2005 - NEJM
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multicenter, randomized, parallel-group trial
2021 patients ; 70 years of age or older
high-grade atrioventricular block
randomly assigned to receive a single-chamber ventricular
pacemaker (1009 patients) or a dual-chamber pacemaker (1012
patients).
 In the single-chamber group, patients were randomly assigned to
receive either fixed-rate pacing (504 patients) or rate-adaptive
pacing (505 patients).
 The primary outcome was death from all causes.
 Secondary outcomes included atrial fibrillation, heart failure
and a composite of stroke, transient ischemic attack or other
thromboembolism
RESULTS
 The median follow-up period was 4.6 years for
mortality and 3 years for other cardiovascular events.
 The mean annual mortality rate was 7.2 percent in the
single-chamber group and 7.4 percent in the dualchamber group (hazard ratio, 0.96; 95 percent
confidence interval, 0.83 to 1.11).
 no significant differences between single-chamber
pacing and dual-chamber pacing in the rates of atrial
fibrillation, heart failure or a composite of stroke,
transient ischemic attack or thromboembolism.
CONCLUSION
 In elderly patients with high-grade atrioventricular
block, the pacing mode does not influence the rate of
death from all causes during the first five years or the
incidence of cardiovascular events during the first
three years after implantation of a pacemaker.
DANPACE
Trial design: Patients with sick sinus syndrome were randomized to single-lead atrial (AAIR)
pacing (n = 707) vs. dual-chamber (DDDR) pacing with an atrioventricular interval of ≤220
msec (n = 708). Mean follow-up was 5.4 years.
Results
(p = NS)
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 Pacing in the atrium: 58% in the AAIR group
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58
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and 59% in the DDDR group; pacing in the
ventricle: 65% in the DDDR group
 Survival: similar between groups (29.6% vs.
27.3%, p = 0.53)
 Paroxsymal atrial fibrillation ↑ with singlelead atrial pacing (28.4% vs. 23.0%, p =
0.024)
 Need for reoperation: ↑ with single-lead
atrial pacing (22.1% vs. 11.9%, p < 0.001)
Conclusions
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Pacing inpacing
the atrium
AAIR
DDDR
• Among patients with sick sinus syndrome, dualchamber pacing appears to be superior to singlelead atrial pacing
• Dual-chamber pacing resulted in reduced
frequency of atrial fibrillation and need for
reoperation
Nielsen JC, et al. Eur Heart J 2011;Feb
7:[Epub]
Effects of pacing modes on various
parameters
AF
 Those with AV block indication for pacing were less
likely to progress to permanent AF when compared to
SND indication for pacing – CTOPP trial
 UKPACE – annual event rates for developing AF
were similar in both dual and single chamber
groups
Stroke , mortality and heart failure
 No difference between dual chamber or single
chamber pacing in the above parameters
Exercise capacity and quality of life
 CTOPP and some short term crossover studies showed
increased exercise tolerance and improved quality of
life by patient symptom scores with dual chamber rate
adaptive pacing when compared to fixed rate
ventricular pacing ( but statistical significance not
attained)
Effect of rate adaptive pacing
Pacemaker syndrome
 PASE
- 26% of patients randomized to VVI mode had severe
symptoms attributable to pacemaker syndrome
– 50% of patients who were programmed to DDD from
VVI mode had AV block
Whereas only 7% of patients in CTOPP needed a pacemaker revision
over a 6 yr follow up period
Pacing mode after AV junction
ablation
 Single chamber pacing is the preferred mode of
therapy for patients who have AV junction ablation for
medically refractory AF
Potential deleterious effects of
ventricular pacing
 No randomized trials available
 Algorithms to minimize ventricular pacing have not
found to be useful in patients with AV block.
 Some case reports have even reported to have
deleterious effects
VDD pacemaker in AV block
 Single lead , dual chamber
 Decreases procedure time and costs
 Restore AV synchrony
 Atrial lead will be a floating bipole and its sensing
function may degrade over time needing revision
 Useful in young patients with CCHB
HYPERSENSITIVE CAROTID SINUS
SYNDROME
Evidence
 No large randomized clinical trials of pacing mode
have been conducted in this syndrome.
 AAI pacing alone has been shown to be ineffective in
this syndrome due to concomitant AV block during
carotid sinus activation
Morley CA, et al. Carotid sinus syncope treated by pacing. Analysis of persistent symptoms and
role of atrioventricular sequential pacing. Br Heart J 1982;47:411– 8
 There is a potential benefit of dual-chamber pacing to
minimize the impact of the vasodepressor response
and prevent pacemaker syndrome.
Evidence
 In a prospective randomized study of pacing vs. no
pacing therapy performed in 60 patients with carotid
sinus syndrome, syncope recurred in 16 (57%) of the
no-pacing group and in only 3 (9%) of the pacing
group (p0.0002)
 18 of 32 (56%) of the paced group received VVI devices
and the remainder received DDD devices
Brignole M, et al. Long-term outcome of paced and nonpaced patients
with severe carotid sinus syndrome. Am J Cardiol 1992;69:1039 – 43
Evidence
 comparisons made between VVI vs. DDDR vs. DDDR with rate drop
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response in patients with carotid sinus syndrome without evidence of
concomitant SND or AV block.
The primary endpoints of syncope or presyncope were significantly
reduced after pacemaker implantation in all three groups
no significant differences in the primary outcomes were demonstrated
among the three pacing modalities.
minor benefits of DDDR pacing was noted vs. baseline in the
categories but no pacing mode was found to be superior.
Despite the physiological hemodynamic advantage of AV synchrony,
the superiority of DDD pacing was not observed in this study
McLeod CJ, Trusty JM, Jenkins SM. Rea RF, Cha Y-M, Espinosa RA.Friedman PA, Hayes DL, Shen
W-K. Method of pacing does not affect the recurrence of syncope in carotid sinus syndrome.
Pacing Clin Electrcrossover study
NEUROCARDIOGENIC SYNCOPE
Trial evidence
Neurocardiogenic syncope
 role of permanent cardiac pacing for neurocardiogenic
syncope remains controversial
 The Vasovagal Pacemaker Study II (VPS 2) reported no
significant reduction in the time to a first recurrence
of syncope during dual-chamber pacing over 6 months
of follow-up
 The Vasovagal Syncope and Pacing Trial (SYNPACE)
also reported that there was no significant difference
between comparison groups
The subgroup of patients who had demonstrated asystole during tilt-table testing
had a significant increase in time to first syncope recurrence compared with those
with bradycardia alone (91 vs 11 days, respectively)
PACING IN NEUROCARDIOGENIC
SYNCOPE
 The ISSUE II trial reported that permanent pacing in
patients with periods of asystole resulted in a
significant reduction in the frequency of syncope.
 In the Syncope and Falls in the Elderly Pacing and
Carotid Sinus Evaluation (SAFE PACE) study,
permanent pacing reduced falls, recurrent syncope
and injuries in elderly patients with frequent
nonaccidental falls and cardioinhibitory carotid sinus
hypersensitivity.
Hypertrophic cardiomyopathy
M – PATHY trial
 48 patients
 Randomized Double blind cross over study
 DDD pacing vs AAI pacing
 Though outflow tract gradient decreased with dual
chamber pacing no much significance was found in
the quality of life between the two groups.
Long QT syndrome
Long QT syndrome
 No randomized trials available
 Indicated in pause dependent VT
 AAI vs DDD vs VVI – direct comparisons not available
 Dual chamber pacing better than single chamber
pacing
Complications – evidence review
Summary
 Compared with ventricular pacing, the use of atrial-
based pacing does not improve survival or reduce
heart failure or cardiovascular death.
 Atrial-based pacing reduces the incidence of atrial
fibrillation and may modestly reduce stroke
Thank you