Transcript Catheter Ablation of Ventricular Tachycardia without

New targets of AF ablation –
CFAE and GPs
Helmut Pürerfellner
Public Hospital Elisabethinen,
Academic Teaching Center
Linz, Austria
Ablation strategy
• Focal (within PV)
• Segmental ostial
• Circumferential atrial
• Additional lines
• Substrate mapping (CAFE,
DF)
• Ganglionated plexus (GP)
Lecture outline
• AF mechanisms
• Definition of complex fractionated
atrial electrograms (CFAE)
• Mechanisms underlying CFAE
• Identification of CFAE
• Automated detection
• Conclusions
Mapping of human AF
• Atrial electrograms during sustained AF:
•
•
single/double/complex fractionated
potentials
Localized to specific sites with
remarkable temporal and spatial stability
CFAE may represent AF substrate sites
and are targets for AF ablation
Definition of CFAEs
•
•
Atrial electrograms that are
fractionated and composed of
≥2 deflections ± perturbation of the
baseline with continuous deflections from
a prolonged activation complex
Atrial electrograms with a
very short cycle length (≤120ms)
± multiple potentials when compared with
atrial cycle length from other parts of the
atria
Identification of CFAEs
• Visual inspection: subjective
judgement, interobserver
variability
• Automated detection: objective
Visual inspection of CFAEs
Visual inspection of CFAEs –
Variable clinical results
• Nademanee et al (JACC 2004):
•
•
•
91% success at 1 year (PAF and CAF)
Oral et al (Circulation 2007):
57% success at 13 months (only CAF)
Verma et al (JCE 2007):
83% success at 13 months (PAF and
CAF vs 72% control group PVAI only)
Takahashi et al (JACC 2008):
90% success at 14 months (only CAF,
combining with PVI and lines)
Characterization of Electrograms associated
with termination of CAF by catheter ablation
Takahashi et al, JACC 2008;51:1003-1010
Characterization of Electrograms associated
with termination of CAF by catheter ablation
Takahashi et al, JACC 2008;51:1003-1010
Characterization of Electrograms associated
with termination of CAF by catheter ablation
Takahashi et al, JACC 2008;51:1003-1010
Characterization of Electrograms associated
with termination of CAF by catheter ablation
Takahashi et al, JACC 2008;51:1003-1010
Automated detection of CFAEs –
Why?
• Very low amplitude (0,06-0,25mV)
• Over a larger area: determination
of exact boundaries
• Very short CL: determination of CL
of a local EGM
• Improvement in detection/
quantification/regionalization
• Consistent definition between
centers
Classification of Fibrillatory Electrograms*
NAE
CFAE
Complex
Fractionated
Atrial
Electrograms
Normal Atrial
Electrograms
Continuous
Fractionated
Electrical Activity
Distinct
Fractionated
Electrograms
*MAPPING OF COMPLEX FRACTIONATED ATRIAL ELECTROGRAMS (CFAE) USING THE CARTO® XP SYSTEM
T De Potter, MD and M Duytschaever, MD,PhD
Automated detection of CFAEs –
CARTO, Biosense Webster
Algorithm:
1. All peaks of bipolar deflections
exceeding ±0.05mV are identified
and tagged white (0.05-0.15 mV) or
purple (>0.15mV)
2. Intervals between 2 successive peaks
of 0.05 to 0.15mV are determined
3. Number of intervals between 70 and
120ms during 2,5 sec recording
period determined (referred as
interval confidence level, ICL)
CFAE Software Operation
•
•
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A point is acquired capturing
2.5 seconds of electrogram
data
Electrograms captured are
analyzed in 2 ways
simultaneously using:
• Voltage Criteria
• Interval Criteria (cycle length)
results are displayed on a
CARTO® XP System map using
the familiar color scheme
and/or local confidence tags
Algorithm Basics Amplitude
• The Upper threshold is set to
include only low amplitude
deflections (avoid ventricular far
field sensing, large amplitide atrial
signal)
• The Lower Threshold is set to
ignore baseline noise (avoid noise
oversensing)
Algorithm Basics Duration
– The Min threshold excludes
deflections that belong to one
complex (avoid overcounting of
a single deflection)
– The Max threshold excludes
deflections that are too far
apart
ICL Threshold
Automated CFAE detection
(CARTO)
Scherr et al, Heart Rhythm 2007
Automated CFAE detection
(CARTO)
Scherr et al, Heart Rhythm 2007
CFAE Maps
• Shortest Complex Interval (SCI):
•
Displays the value of the shortest
interval between two consecutive
CFAE in the signal
Interval Confidence Level (ICL): If
there are two or more adjacent CFAE
complexes in the signal, the ICL
displays the number of CFAE intervals
• Average Complex Interval (ACI):
Displays the average value for all
CFAE complex intervals in the signal
Automated detection of CFAEs –
Ensite NavX, St. Jude
Algorithm:
• measures the time between multiple
discrete deflections (-dV/dT) in a local
recording over a specified length of time
(5 seconds)
• averages these interdeflection time
intervals to calculate a mean CL of the
local EGM during AF
• Mean CL projected onto LA anatomical
shell colour coded
• CFEs exhibiting a mean CL <120ms
CFAEs detection steps–
EnSite NavX, St. Jude
1.
2.
3.
All bipolar EGM peaks with a
voltage amplitude ≥twice
the maximal noise amplitude
of the baseline
Refractory period from the
previous detection set
CFE mean values obtained
CFAEs detection steps–
EnSite NavX, St. Jude
•
•
Refractory: limits
double counting
Width: limits
detection to high
frequency signals
10-15
5sec
35-50
CFAE detection – EnSite NavX
Automated detection of CFAEs –
Various aspects
• Minimal recording duration per
site
• Temporal stability over AF
ablation procedure
Consistency of CFAE –
correlation between 1-7 vs 8 seconds
Lin et al, Heart Rhythm 2008;5:406-412
Consistency of CFAE –
FI variation between 1-7 vs 8 seconds
Lin et al, Heart Rhythm 2008;5:406-412
Consistency of CFAE –
Regional distribution 1 vs 8 seconds
Lin et al, Heart Rhythm 2008;5:406-412
Consistency of CFAE –
Comparison of FI and DF
Lin et al, Heart Rhythm 2008;5:406-412
CFAE distribution and
temporal stability
Roux et al, JCE 2008
CFAE distribution and
temporal stability
Roux et al, JCE 2008
Mapping
• Mapping methodology is not changed
• Detailed baseline map is recommended
•
•
(>80 points) in SR or AF
Induction of AF is necessary
CFAE areas may be further mapped and
explored for more CFAE locations
(dedicated CFAE mapping)
Endpoints for CFAE ablation
• Transformation from complex to
discrete electrograms
• Complete elimination of areas with
CFAE
• Slowing
• Organization in atrial tachycardias,
atrial flutter
• Conversion to SR
Ablation of CFAE resulting in
termination
Courtesy of Dr Aichinger/Dr Pürerfellner, Linz, Austria
Is fractionation the AF substrate?
(Active vs passive CFAEs)
PRO:
• Identify critical pivot
points
(multiple wavelets)
• Unmask nearby rotors
(focal sources)
• Identify enhanced GP
activity
(neural conduction)
CONs:
• Occur during passive
activation,
CL dependency
• Just a marker of
structural complexity
(stationary,
preferential sites)
• Noise
DF changes in PAF
DF changes in CAF
Conclusions 1
• The contribution of electrogram based
•
•
•
strategies to procedural success in AF
ablation is an area of active
investigation
CFAEs with varying degrees of
fractionation are found in >80% of LA
endocardial/ epicardial locations during
ongoing AF
CFAE can be quantified by automated
detection algorithms
There is considerable CFAE variation
which is critically dependent on the
degree of fractionation and on the
recording duration
Conclusions 2
• Sites with consistent and a high degree
•
•
•
of fractionation exhibit continuous
activation which may define a site
actively involved in the fibrillatory
process (ablation target!)
Automated detection of CFAE may
therefore provide a widely applicable
tool including an electrophysiological
endpoint for more extensive ablations
targeting the AF substrate
However, there is still a a paucity of
randomized trials and particularly of
multicenter trials
Further studies are clearly needed
Primum non nocere
« I will follow that system of regimen which,
according to my ability and judgement, I consider
for the benefit of my patients, and abstain from
whatever is deleterious and mischievous. »
Ablation strategy
• Focal (within PV)
• Segmental ostial
• Circumferential atrial
• Additional lines
• Substrate mapping (CAFE,
DF)
• Ganglionated plexus (GP)
Programmed electrical nerve stimulation
(PENS) and GP ablation
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•
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Requires high rates and strengths of stimultion
(appr. 10-15 times more than PES)
Distal tip of map/ablation catheter deivering
typically 1200 bpm (20Hz) with a pulse width of
10ms at 5 to 15 V
High frequency stimulation (HFS) during SR at GP
areas induces AFib (by local release of
Acetylcholine) and CAFEs
HFS during AFib induces vagal response (AV block
and hypotension) within 10 sec
Ablation directly over GP area infrequently causes
symptoms
HFS after ablation fails to reinduce vagal
response (eliminates afferent response)
HFS
GP ablation
Nakagawa et al, Heart Rhythm 2006
GP ablation
GP ablation
• Future role: unclear
• Adjunct to conventional
ablation strategies ?