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The EP Show:
Right ventricular vs biventricular pacing
Eric Prystowsky MD
Director, Clinical Electrophysiology Laboratory
St Vincent Hospital
Indianapolis, IN
Bruce Wilkoff MD
Director, Cardiac Pacing/Tachyarrhythmia Devices
Cleveland Clinic
Cleveland, OH
Leslie Saxon MD
Director, Department of Electrophysiology
USC University Hospital
Los Angeles, CA
Michael Gold MD
Chief, Division of Cardiology
Medical University South Carolina
Charleston, SC
EP Show
Right ventricular vs
biventricular pacing
Can long-term right ventricular
pacing actually hurt the heart?
June 2004
EP Show
How to pace?
"Systole is better than asystole."
•
If the heart needs to be paced, and
there is heart block, the ventricle
needs to be paced somehow
CONTROVERSY
•
Pacing the atrium in AAI mode vs
pacing in VVI or DDD modes
•
Europeans lead way in promoting
atrial pacing over ventricular
pacing
June 2004
Wilkoff
EP Show
The data
Data clear that wall-motion abnormality
produced when ventricle is paced
• DDD vs VVI, as well as other
trials, all include ventricular
pacing
• Danish observational data
suggest there is a mortality
benefit with atrial pacing
June 2004
- Wilkoff
EP Show
DAVID
Dual-Chamber and VVI Implantable
Defibrillator
Comparison of ICD therapy with dualchamber pacing vs ventricular backup
pacing
June 2004
EP Show
DAVID trial: DDDR-70 vs VVI-40
programming
End point
DDDR-70
(%)
VVI-40 Relative risk
(%)
(95% CI)
Event-free
survival at 1
year
73.3
83.9
1.61 (1.06-2.44)
Mortality
10.1
6.5
1.61 (0.84-3.09)
CHF
hospitalization
22.6
13.3
1.54 (0.97-2.46)
The DAVID trial investigators. JAMA 2002;
288:3115-3123.
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DAVID trial
Pacing really caused a significant
detriment to these patients
• The change in mortality and HF was
equal to the benefit of amiodarone
seen in the original AVID trials
• Large effect on HF and mortality
without RV pacing, at least in
patients who needed
defibrillators and
had ventricular dysfunction
June 2004
Wilkoff
EP Show
Landmark study
In some ways, the DAVID trial is one of
the first randomized pacing trials
• Treatment vs nontreatment group
• First trial to show an isolated effect of
DDDR pacing and RV pacing on HF and
mortality
June 2004
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MADIT II
• Consistent with DAVID, MADIT II
patients with dual-chamber
defibrillators had a higher rate of
hospitalization for heart failure than
those with single-chamber devices
• Consensus emerging that RV pacing
may be hurting patients
• Trying now to get the benefit of
an atrial lead without
ventricular pacing
June 2004
Gold
EP Show
Biventricular pacing
• Resynchronization therapy performed
with simultaneous RV and LV pacing;
or pace with LV alone
• Most data with biventricular pacing in
symptomatic HF patients with
conduction disease
June 2004
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Biventricular pacing
• Patients feel better and exercise more,
systolic response improves, and
possible reverse remodeling
• Sickest patients appear to live longer
and require fewer hospitalizations
June 2004
EP Show
Biventricular pacing
What about the brady-indicated patient
who does not meet criteria for CRT?
Help vs harm
What is the risk of RV-pacing-induced
left bundle branch block?
How will this hurt the patient in the
short and long term?
June 2004
- Saxon
EP Show
Biventricular pacing
"I think in some patients, chronic RV pacing
will cause left ventricular dysfunction."
• Not a majority
In patients with LV dysfunction but with
native left bundle branch block, RV pacing
will not likely make that ventricle worse
• May be improved with biventricular
pacing, but requires careful
evaluation
June 2004
Saxon
EP Show
A recurring question
What about the patient with chronic RV
pacing and LV dysfunction who comes to
the lab for an elective battery replacement?
• Upgrade to CRT represent "half of what
I'm doing these days"
• Begin to think about the patient under
the criteria of other prophylactic studies,
such as MADIT II and SCD-HeFT
June 2004
- Saxon
EP Show
How is the LV paced?
LV pacing achieved similar to right-sided
implants
• LV lead placed into the venous system
• LV branch vein accessed through the
coronary sinus great cardiac vein
• Coronary sinus accessed in a retrograde
fashion from the lower right atrium
• Guide catheter employed into the great
cardiac vein, with lead deployed
into branch vein to pace the left
ventricle
June 2004
- Saxon
EP Show
Negative effects of RV pacing
Not only does chronic RV pacing induce
LV dyssynchrony, but even if atrial
transport is maintained in DDD mode,
there is an increased risk of atrial
fibrillation, in addition to the increased
risk of heart failure
June 2004
Saxon
EP Show
Indications for biventricular pacing
INDICATIONS
• Patients with class 3 or 4 heart failure,
despite optimal medical treatment
• EF <35%
• Wide QRS interval (at least 120-130 ms)
• Left bundle branch block patient (typically)
June 2004
EP Show
AF data
"I think the AF data are difficult and
confusing."
• Lack of P wave needed to pace
ventricle
"The data we do have suggests these
patients can benefit if you can
achieve frequent, if not
continuous, biventricular pacing."
June 2004
Gold
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Recent answers
Who gets a defibrillator? Two major trials:
SCD-HeFT
Sudden Cardiac Death in Heart Failure
Trial
COMPANION
Comparison of Medical Therapy,
Pacing, and Defibrillation in Heart
Failure
June 2004
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SCD-HeFT mortality data
All-cause
mortality
ICD
Amiodarone
Placebo
3 years (%)
17.1 24.0
22.3
5 years (%)
28.9 34.1
35.8
Bardy G. American College of Cardiology 2004 Scientific Sessions;
Mar 7-10, 2004; New Orleans, LA.
EP Show
COMPANION: 12-month outcomes
End point
OMTa,
n=308
(%)
Plus
CRT,
n=617
(%)
HR
(95%
CI)
pb
Plus
CRT/ICD,
n=595
(%)
RR
(95% CI)
pb
All cause
mortality/
hospitalization
68
56
0.81
(0.690.96)
0.015
56
0.80
(0.680.95)
0.011
All-cause
mortality
19
15
0.76
(0.581.01)
0.06
12
0.64
(0.480.86)
0.004
a OMT=Optimal medical therapy
b p vs optimal medical therapy without device therapy
HR=hazard ratio
CI=confidence intervals
Bristow MR et al. N Engl J Med 2004; 350:2140-2150.
EP Show
Impact
SCD-HeFT and COMPANION
"Those studies have certainly made
us move more and more toward
combining defibrillators with
biventricular pacing in a majority of
our patients."
June 2004
Gold
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CRT plus a defibrillator
Is it fair to say that if patients meet the
criteria for biventricular pacing, they
will also have an indication for a
defibrillator?
- Prystowsky
Yes, the clinical data support it.
- Gold
June 2004
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Biventricular pacemaker or
defibrillator?
"There is another issue here and it has to
do with reimbursement. We have to
bring in who is going to pay for this."
• Still some "fuzziness" to NYHA
functional class
• How do we treat the NYHA class 2 HF
patients?
• Reimbursement decision
expected from CMS by
September 2004
June 2004
Wilkoff
EP Show
Nonischemic HF
• Very little data to support the use of
defibrillators in dilated nonischemic
cardiomyopathy patients
DEFINITE study
• Medically managed HF patients with
nonischemic cardiomyopathy implanted
with an ICD showed a nonsignificant
reduction in all-cause mortality with device
therapy
"We're in a little bit of a bind here. We have
some good clinical data, but we don't have
administrative approval to be putting
defibrillators in all these patients."
June 2004
- Wilkoff
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Social issues
"There are a number of people that just don't
relate to the concept of having an
implantable defibrillator."
• Need to discuss implications, but in
general, if presented properly, most
patients will want the device; others will
refuse
• In ischemic patients, where there is
reimbursement, we should be pushing for
biventricular defibrillator devices
June 2004
Wilkoff
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Patient selection
OTHER INDICATORS
• Wall motion indices as possibly superior
to QRS duration?
• Response rates, in terms of clinical
improvement, can be frustrating,
especially in patients who meet
standard criteria
June 2004
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Other indicators
The wider the QRS, the greater the
probability of benefit
• But QRS is a surrogate marker so
there is a need to look for other,
more direct, measures of
dyssynchrony
• Echo and nuclear measures as
possible predictors of patient benefit
June 2004
Gold
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More data needed
"I think this is an evolving field that's
very interesting in trying to select these
patients, but unfortunately we don't
have long-term outcome data using
these measures."
June 2004
- Gold
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Not there yet
Mechanical dysfunction identified
typically by an ECG
"It's not really the disease. It is a
surrogate for the wall motion
abnormality that we're trying to correct
with an electrical answer."
"It is likely that we're going to have
better measures for dyssynchrony and
we're going to find better ways of
identifying patients."
- Wilkoff
June 2004
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The future
• Moving toward resynchronization in a
larger group of patients
• Need for studies to determine whether
various imaging indices can
prospectively identify responders
"Right now, these imaging methods are
really experimental and should not
be used as selection criteria."
June 2004
Saxon
EP Show
The future
Issue of whether the ventricle can
resynchronized with LV pacing alone is
fascinating
• Early European data showing that LV
pacing alone can improve the "feelgood" parameters as much as
biventricular pacing
• Echo studies preliminary, but
comparable
• QRS actually widens
June 2004
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The future
• New studies in brady-indicated patients
randomized--regardless of LV function-to biventricular/LV pacing vs RV pacing
alone
• Issue of who needs defibrillation has
been worked out by the ICD trials that
will trump indications for these patients
currently under FDA approval
June 2004
EP Show
Off-label use
BEDSIDE PRACTICE
"You can't always wait for trials."
- Prystowsky
"I'm maybe more conservative than
others, having been through the wars of
biventricular pacing."
- Gold
June 2004
EP Show
Off-label use
"In general, if I have a patient with
preserved LV function who is going to
be pacing, whether because I've
created complete heart block with an
ablation or because they have intrinsic
AV node disease, I will still tend to RV
pace them. I know that's a safe, simple,
reliable system."
June 2004
Gold
EP Show
The guy in the corner
"Am I the only person who is pacing some
selected patients with a biventricular
system that aren't in class 3 or 4 heart
failure?"
- Prystowsky
"No, I'm doing it, Eric."
- Saxon
• PAVE trial showed improved exercise
capacity in less symptomatic patients
who were implanted with a
biventricular device
June 2004
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Caution urged
• However, subanalysis in PAVE showed that
the improvement was only in patients with
EF <40%
• There was no benefit in patients who had
preserved EF
• Study overall had a statistically significant
end point, but subgroups had
disparate results
June 2004
Gold
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Not hypothetical
"These are not general and new
guidelines. These are totally off the
guidelines."
But the technology is available and it is
not hypothetical. Clearly, it is a patientby-patient discussion
June 2004
Prystowsky