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Transcript of Govil, Calkins, Spragg - 2011 - Fusion of Imaging Technologies How, When, And for Whom-Annotated
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Fusion of imaging technologies: how, when, and for whom?
Ashul Govil & Hugh Calkins & David D. Spragg
Received: 3 November 2010 /Accepted: 14 August 2011 /Published online: 1 October 2011# Springer Science+Business Media, LLC 2011
Abstract Over the past decade, electroanatomic mapping
has emerged as a useful tool for complex ablation
procedures. A more recent advancement is the development
of image integration. Image integration refers to the processof registering a previously acquired MRI or CT scan of the
heart with the mapping space during the ablation procedure.
The technique of image integration is now relied on by
many electrophysiology laboratories to guide complex
ablation procedures, particularly atrial fibrillation ablation
and ablation of patients with ventricular tachycardia in the
setting of structural heart disease. An even more recent
development is image fusion. This refers to taking
information about the myocardial substrate, especially
intramyocardial scar, and registering it with the active
mapping space. This technique remains in its infancy but
shows great promise in facilitating complex ablation
procedures. The purpose of the article is to review the
development, state of the art, and future of these image
integration and fusion techniques.
Keywords Imaging technologies . Fusion . Image
integration . Ablation . Mapping
1 Introduction
During the past 20 years, tremendous advances have been
made in the tools used to perform ablation procedures.
When radiofrequency ablation was discovered to be a safe and
effective therapy for many types of cardiac arrhythmias two
decades ago, ablation procedures were guided by fluoroscopic
imaging as well as intracardiac electrograms. Mapping wasused to identify the earliest site of atrial or ventricular
activation, the presence of discrete electrical signals such as
accessory pathway potentials, mid-diastolic potentials, or the
His bundle, or evidence of a slow zone of conduction critical
for reentrant arrhythmias such as ventricular tachycardia and
atrial flutter. Although these mapping tools proved to be more
than adequate for guiding catheter ablation of accessory
pathways , atrioventricular nodal reentran t tachycardia
(AVNRT), atrial flutter, and idiopathic ventricular tachycar-
dia arising in the right ventricular outflow tract, they were far
less helpful in guiding ablation of complex arrhythmias.
Today, the field of catheter ablation has changed dramatically.
Whereas ablation of accessory pathways and AVNRT kept
electrophysiologists fully occupied 20 years ago, the focus has
shifted to catheter ablation of more complex arrhythmias
including atrial fibrillation, complex atrial tachycardias, and
ventricular tachycardia. The great progress made in ablating
these more challenging arrhythmias can be attributed, in a
large part, to the development and perfection of three-
dimensional (3-D) mapping systems. These currently include
the Biosense Webster Carto system and the St. Jude Medical
NavX system. Even more recently, it has become possible to
take advantage of the detailed anatomic information provid-
ed by intracardiac echocardiogram, CT, and MRI scans of the
heart through the use of image integration. The purpose of
this article is to provide a state-of-the art review of image
integration today and also to look toward the future.
2 Three-dimensional mapping systems
There currently are two main 3-D mapping systems which
are in wide spread clinical use in the USA. Although both
A. Govil
Department of Medicine, Johns Hopkins Bayview Medical Center,
Baltimore, MD, USA
H. Calkins : D. D. Spragg (*)
Division of Cardiology, The Johns Hopkins Hospital,
600 N. Wolfe Street, Carnegie 568,
Baltimore, MD 21287, USA
e-mail: [email protected]
J Interv Card Electrophysiol (2011) 32:195 – 203
DOI 10.1007/s10840-011-9616-7
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of these systems are capable of accurately localizing a
mapping site or ablation point in three-dimensional space,
the technologies used to accomplish this differ, as do some
important ancillary features.
The first three-dimensional mapping system to be
developed was the Biosense Webster Carto XP system.
The CARTO system uses magnetic technology to accurate-
ly determine the location and orientation of the mapping/ ablation catheter and simultaneously records the local
electrogram from its tip. Sampling a sufficient number of
endocardial sites allows for reconstruction of the three-
dimensional geometry of the chamber, with the electro-
physiological information color-coded and superimposed
on the anatomy (Fig. 1). The system has been shown to be
highly accurate in both in vitro and in vivo studies [1]. The
mapping and navigation system is comprised of a miniature
passive magnetic field sensor, an external ultra-low mag-
netic field emitter (location pad), and a processing unit
(CARTO, Biosense). The locatable catheter is similar to a
regular electrophysiological 8F deflectable-tip catheter. Thecatheter tip is mounted on the distal end of the shaft and
includes the tip electrode and several additional proximal
electrodes that enable recording of unipolar or bipolar
signals. Just proximal to the tip electrode lies the location
sensor, totally embedded within the catheter. Signals
received within the sensor are transmitted along the catheter
shaft to the main processing unit. The locator pad is located
beneath the operating table and generates ultra-low mag-
netic fields (5×10−6 to 5×10−5 T) that code the mapping
space around the patient's chest with both temporal and
spatial distinguishing characteristics. These fields contain
the information necessary to resolve the location and
orientation of the sensor in six degrees of freedom ( x, y, z ,
roll, pitch, and yaw). The locator pad includes three coils.
Each coil generates a magnetic field that decays as a
function of the distance from that coil. The sensor measuresthe strength of the magnetic field, thus enabling determi-
nation of the distance from each of its sources. These
distances determine the radii of theoretical spheres around
each coil. The intersection of these three spheres determines
the location of the sensor in space. The location of the
mapping catheter is gated to a fiducial point in the cardiac
cycle and recorded relative to the location of the fixed
reference catheter at that time.
A second three-dimensional mapping system that is
currently available clinically is the NavX system (Endocar-
dial Solutions Inc., St. Paul, MN, USA) [2, 3]. This system
utilizes regular mapping and ablation catheters to sense a 5.6-kHz, low-current electrical field generated in the thorax
by externally placed electrodes. It has the ability to generate
an anatomic map and superimpose the locations of up to 64
catheter electrodes upon the map. A three-dimensional
computer model of the left atrium (LA) can be created by
dragging the ablation or multipolar catheter on the
endocardial surface and in each of the pulmonary veins
(PVs; Fig. 2). This nonfluoroscopic navigation system can
LAO Lateral
Fig. 1 CARTO mapping of the left ventricle, showing left anterior
oblique ( LAO) and lateral projections. The voltage maps demonstrate
a large inferior region of scar extending from the mitral valve ( white
ring ) to the ventricular apex. Dense scar is shown in grey, diseased
peri-infarct tissue is shown in red , and normal tissue in purple
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display anatomic structures in three dimensions, includingthe precise location of PV ostia, as well as the relative
position of catheters and the sites of radiofrequency
application.
More recently, there has been the development of the
CARTO 3 system that improves on the original CARTO
system. CARTO 3 was recently released and makes
several improvements on the original system. Like the
original CARTO system, CARTO 3 uses magnet-based
localization for visualization of the catheter and map-
ping, but the new system incorporates nine magnets
within the locator pad as opposed to the original six
that may allow for greater accuracy and compensation
for patient movement. Unlike the original CARTO
system, CARTO 3 also allows for non-gated mapping
of the catheter. In addition, the new system merges the
magnet-based system with a new impedance-based
technology. The merging of magnetic- and impedance-
based technologies along with non-gated timing allows
for both tip and catheter curve visualizations as well as
simultaneous visualization of multiple electrodes, unlike
the original CARTO system that only allowed for
single-catheter tip visualization (Fig. 3). These features
also allow for fast anatomical mapping which utilizes
small fluctuations in catheter measurement of impedance.
This makes it possible to generate an electroanatomical
map and simultaneously to add electroanatomic informa-
tion without the need for point-by-point selection and
recording of electrograms. Although the system is rela-
tively new, two studies comparing various electroanatomic
mapping systems suggest the new features of the CARTO
3 results in significantly lower procedure and fluoroscopy
times than traditional fluoroscopy or older electroanatomic
mapping systems [4, 5].
3 Three-dimensional mapping systems and AF ablation
Although the original three-dimensional mapping systems
were developed prior to the era of atrial fibrillation (AF)
ablation, their widespread clinical use only occurred after it
was shown that the best outcomes of AF ablation could be
achieved with the use of three-dimensional mapping
systems to guide wide area circumferential pulmonary vein
isolation. Initial attempts at catheter ablation for AF relied
on the identification and ablation of focal triggers [6 – 8], but
it was quickly appreciated that this approach had many
limitations. These included the fact that most patients have
no active triggers during their ablation procedure and those
that did frequently had multiple foci arising from multiple
PVs. Furthermore, the approach to AF ablation directed at
arrhythmogenic foci resulted in radiofrequency (RF) delivery
within PVs which was subsequently shown to result in PV
stenosis or occlusion [9, 10].
Because of these limitations, anatomically based strate-
gies for catheter ablation of AF emerged. One of these
approaches employs a circumferential mapping catheter
which is deployed sequentially in each of the four PVs.
Although this approach was championed by several centers
throughout the world, it was ultimately discovered that the
best results of AF ablation are accomplished with an
alternate strategy, wide area circumferential ablation [11].
This strategy involves the delivery of RF energy to the
entire circumference of all PVs by the creation of circular
lesions just outside each PV ostium or the creation of two
larger circumferential lesions around the two right and the
two left PV ostia. The endpoint of this approach is complete
electrical isolation of all PVs. As these new anatomically
driven ablation strategies emerged, accurate mapping of left
atrial structure (in conjunction with local electrogram data)
Fig. 2 NavX map of the left
atrium, showing an AP view.
The left atrial appendage (dark
purple), left superior and
inferior pulmonary veins (light
purple and brown, respectively),
and right superior and inferior
pulmonary veins (tan and
yellow, respectively) are identi-
fied, and an intracardiac catheter ( green) is seen at the posterior
aspect of the left atrium
J Interv Card Electrophysiol (2011) 32:195 – 203 197
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becam e paramou nt. The three-dim ensiona l map ping
systems discussed above provided (and continue to
provide) that mapping abil ity, allo wing for the safe
delineation of vital structures including the atrial walls, left
atrial appendage, pulmonary veins, and mitral annulus.
4 Image integration — from novel tool to standard
practice
4.1 Initial proof-of-concept studies
Image integration, the technique whereby three-dimensional
CT or MRI images are registered with the heart during the
mapping and ablation procedure, was first reported in 2003 in
an animal model [12, 13]. In these initial studies, we
demonstrated that a previously acquired MRI image could
be successfully registered with the animal’s heart and used to
both navigate and also deliver RF energy applications. The
following year, we reported the first human use of image
acquisition [14]. Prior to obtaining the MRI, nine standard
surface skin markers were placed on the chest and included
in the MRI image. These areas were then marked so that they
could be reapplied the following day when the procedure
was performed. Image registration, the process that super-
imposes the catheter mapping space with the MRI, was
performed by placing the ablation catheter at each skin
marker and correlating it with the corresponding imaged
marker. Registration required between 10 and 12 min. At
that point, the ablation catheter was successfully navigated
throughout the right atrium, superior vena cava, and right
ventricle. In this initial system, the catheter tip was
simultaneously displayed in coronal, sagittal, and axial
views. The accuracy of this external registration had a
precision and accuracy of 1.2 ± 0.4 and 9.5 ±4.2 mm,
respectively. Although we demonstrated the feasibility of
this approach, further optimization of position error was
required before this could be used as a standard clinical tool.
4.2 Commercial system development
The next major step in the clinical development of image
integration was the development of the CartoMerge system
by Biosense Webster and the NavX Fusion by St. Jude
Medical. We performed the initial study using CartoMerge
in a canine model to test the true accuracy of image
integration techniques for each cardiac chamber and to
evaluate its feasibility to facilitate clinical ablation proce-
dures [15]. This initial trial was performed in eight mongrel
dogs. Targeted ablations were performed at previously
placed fiducial markers guided only by reconstructed 3-D
images. At autopsy, the position error was 1.9±0.9 for the
right atrium, 2.7±1.2 for the right ventricle, 1.8±1.0 for the
left atrium, and 2.3±1.1 mm for the left ventricle. Ablations
Fig. 3 Carto3 map of the left
atrium (with CT merging; PA
projection), showing multiple
catheters projected onto the
mapping surface. A lasso map is
in the right inferior pulmonary
vein, while the ablation catheter
is below the ostium of the left
inferior pulmonary vein. The CS
catheter is also shown (belowthe LA body)
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were also performed of the cavotricuspid isthmus, fossa
ovalis, and pulmonary veins. The associated position error
was 1.8±1.5, 2.2±1.3, and 2.1±1.2 mm, respectively. We
concluded from this initial evaluation of the system that
image integration with high-resolution 3-D CT allows
accurate placement of anatomically guided ablation lesions
and can facilitate complex ablation strategies.
The next step was to use this system to guide a clinical AF ablation. This was accomplished later that
year [16]. The system was successfully used to guide a
circumferential PV ablation in a 60-year-old man. And
the following year, we reported using this system to guide
AF ablation in 16 patients [17]. A preprocedure MRI was
obtained in eight patients, and a preprocedure CT scan
was obtained in eight patients. Using the CartoMerge
software package, the left atrium and PVs were segment-
ed. The segmented 3-D image was accurately registered
to the mapping space with a combination of landmark
and surface registration techniques. The registered 3-D
images were then successfully used to guide circumfer-ential PV isolation. The distance between the surface of
the registered 3-D image and the multiple electroana-
tomic p oints was 3 .0 5 ± 0 . 41 mm. T he re were n o
complications.
In a subsequent study, we evaluated with impact of heart
rhythm status on registration accuracy in a series of ten
patients [18]. Extensive mapping was performed with each
patient in both sinus rhythm and atrial fibrillation. The
results of this study revealed that registration error did not
differ between LA registrations conducted during the same
versus different rhythm as was present during CT imaging.
These findings were reassuring and suggested that, if a
patient ’s rhythm changes during an ablation procedure, the
image does not have to be reregistered.
Since publication of this small series of patients in 2006,
we have relied on image registration of previously acquired
MR or CT images to guide all of our AF ablation
procedures at Johns Hopkins (Fig. 4(a)). We also rely on
it to guide ablation of idiopathic ventricular tachycardia
(VT), ischemic VT, atypical atrial flutter ablation, and focal
premature ventricular contraction ablation, as CartoMerge
allows for image integration of all chambers and major
vascular structures that might include ablation target sites
(Fig. 4(b)).
4.3 Ultrasound imaging
Another advancement in image integration has been the
development of the CartoSound system (Biosense Webster)
that allows for image integration of electroanatomic
mapping with 3-D intracardiac echocardiogram (ICE)
through the combination of a catheter tip that has both a
navigation sensor and ultrasound phased array probe
(Fig. 5). Although ICE has been around for many years,
Khaykin et al. performed the first feasibility study
integrating it with electroanatomic mapping with the use
of Carto Sound in 2008 [19]. Traditional CT and MRI
image integration involves pre-procedure acquisition,
which is subject to distortion because of differences in
cardiac cycle [20], differences in respiratory phase [21],
atrial deformation from intraprocedure catheter manipula-
tion, or from anatomical/physiologic changes that occur
between the time of image acquisition and intraprocedure
registration [22]. Although we have previously demonstrated
prototype models for MRI use during ablation procedures
[23, 24], one of the potential advantages of ICE is that it is
the only widely available system compatible with current
electroanatomic systems that provides real-time anatomical
information. In addition, ICE acquired images merged with
electroanatomic mapping can then be merged with preproce-
dural CT or MRI. In an industry-sponsored study, Okumura
et al. found, in both a feasibility animal study and subsequent
study of ablation in 15 patients with atrial fibrillation, that
Fig. 4 (a) CartoMerge map of the left atrium, shown in PA projection.
CT imaging of the left atrium and pulmonary veins was performed
prior to electrophysiology study and ablation. Circumferential ablation
lesions (brown dots) around the PV ostia are shown. ( b) CartoMerge
image of all four cardiac chambers and associated vasculature, shown
in AP projection. RA, blue; RV, green; PA, yellow; LA, purple; LV,
aqua; aorta and coronary arteries, red
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ICE constructed imaging may allow for more accurate
registration than with CT image integration alone [25].
4.4 Efficacy studies
Several studies performed to define the clinical benefit
of image integration as compared with ablation guided
only with a standard electroanatomic mapping system
have generated mixed results. Martinek et al. compared
outcomes in 53 patients who underwent ablation with a
standard mapping system versus 47 patients who
underwent ablation guided by an electroanatomic map-
ping system with image integration (CartoMerge; [26]).
The long-term success rate of catheter ablation with image
integration was 85%, compared with 68% in patients with
electroanatomic mapping alone. No PV stenosis was seen
in the patients who were ablated with image integration,
while three instances of PV stenosis were seen in the
patients whose ablation was only guided by standard
mapping. A potential flaw in the design of the study was
that the procedures were not randomized but were
performed in a sequential series fashion. This flaw was
subsequently addressed in a study by Della Bella et al.
[27]. In this report, 290 consecutive patients were
prospectively randomized to undergo ablation with stan-
dard electroanatomic mapping or with image integration
mapping. At more than a year of follow-up, AF recurrence
was less common among patients who underwent ablation
using an image integration system (19% recurrence versus
48%). They concluded that image integration results in
superior long-term outcomes. A similar improvement in
the efficacy of AF ablation guided by image integration
has also been reported by Bertaglia et al. [28] and by
Hunter et al. [29].
Other studies of image integration have yielded negative
results. In a prospective study, Kistler et al. randomized 80 patients with AF to undergo first-time ablation using
standard mapping alone or with CT image integration
(CartoMerge) [30]. They found no significant difference in
single procedure success at 6 months between the electro-
anatomic mapping (56%) and image integration (50%)
groups ( P =0.9). The complication rate was similar, and
there was one case of PV stenosis seen in the standard
mapping group compared with no cases in the image
integration group. Similarly, studies by Tang et al. and
Caponi et al. also found no difference in clinical outcomes
at 12 months with the use of CT and MRI image integration
system, respectively, and both showed similar complicationrates [31, 32]. However, although there was no difference in
clinical outcome of the arrhythmia, both of these studies did
find significantly reduced fluoroscopy time in the image
integration groups.
5 Image fusion of scar maps to guide ablation of VT
and atrial fibrillation
The next step in the development and utilization of image
integration software to guide ablation has been the
incorporation of scar maps from previously acquired
positron emission tomography (PET) or MRI images.
Dickfeld et al. were the first to report this in 2008 [33]. In
this initial series, 14 patients underwent PET/CT multi-
modality imaging before VT ablation. The PET/CT-derived
scar maps were used to characterize myocardial scar using a
17-segment analysis and surface reconstruction. In ten
patients, reconstructed 3-D metabolic scar maps were
integrated into a clinical mapping system and compared
with high-resolution voltage maps. A good correlation was
found between the PET/CT-derived scar maps and the
voltage maps. They also demonstrated that 3-D metabolic
scar maps accurately displayed endocardial and epicardial
surfaces and could be successfully integrated with a
registration error of 3.7±0.7 mm. These authors found that
a combination of visual alignment and surface registration
was most accurate for myocardial scar accounting for <15%
of the LV surface. Voltage map findings correlated closely
with scar size, location, and borderzone. Integrated scar
maps revealed metabolically active channels within the scar
not detected by voltage mapping and correctly predicted
non-transmural scar despite normal endocardial voltage
Fig. 5 CartoSound image of the left atrium and pulmonary veins,
shown in right superior PA view. Circumferential ablation around the
PV ostia and across the LA roof is shown ( brown dots) [25]
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recordings. These authors concluded that PET/CT fusion
imaging is able to accurately assess left ventricular scar
and its borderzone. They also showed that the integra-
tion of a 3-D scar map into a clinical mapping system
is feasible and may allow supplementary scar character-
ization that is not available from voltage maps alone.
They further predicted that this system could facilitate
substrate-based VT ablation. In a subsequent study, Tianet al. published a case report describing a 57-year-old
man with a prior myocardial infarction who was
scheduled for VT ablation [34]. Prior to the procedure,
a PET/CT was obtained. The 3-D PET/CT LV and scar
data sets, as well as the delayed-enhancement MRI (DE-
MRI) 3-D reconstruction were co-registered. The 3-D CT
images allowed identification of the LV wall thickness and
epicardial and endocardial surfaces. Wall thinning was
observed only in areas with decreased endocardial voltage
or <1.5 mV, suggestive of scar or borderzone. The 3-D
PET images showed metabolic scar and borderzone at the
apex and the inferior wall that matched the voltage-derived areas of scar and borderzone. The DE-MRI scar
locations were consistent with the voltage-derived scar;
however, the MRI scar was 20% to 30% larger. No VT
could be induced, so a substrate-guided ablation procedure
was performed. Mapping was guided by the registered 3-D
scar. This study was important as it described, for the first
time, the use and value of integrating scar images from a
prior MRI or PET scan, co-registering them with a CT
image and using these data to help guide VT ablation.
More recently, Tian et al. used a contrast-enhanced CT
scan to identify scar. In a series of 11 patients, they
demonstrated that they could characterize LV anatomy and
3-D scar/borderzone substrate [35]. Integration of these
3-D data sets into a clinical mapping system provided
supplementary information as compared with voltage
mapping alone.
In addition to these investigators, our group at Johns
Hopkins has also been pursuing scar imaging and registra-
tion of these images to guide VT ablation. However, instead
of using contrast CT scans to characterize scars, we have
been using delayed-enhancement MRI imaging. We have
previously shown in an animal model that MRI images
accurately correlate with scar and can also correlate well
with inducible VT circuits [36]. We have also characterized
scar patterns in patients with cardiomyopathy (Fig. 6). We
are now embarking on a prospective randomized clinical
trial to determine if importing scar into an electroanatomic
mapping system improves the outcomes of VT ablation. In
our opinion, this is very likely to become a clinically
valuable tool.
The next step will be to use the same approach for
AF ablation procedures. A challenge that must be
faced, however, is the greater difficulty in visualizing
scar in the thin-walled atrium as compared with the
ventricle. However, recent advancements in cardiac
MRI have allowed for better visualization of the atrium
following ablation procedures [37]. McGann et al.
looked at 46 patients undergoing pulmonary vein isola-
tion for AF and took DE-MRI images before and 3 monthsafter ablation. They found that recurrence of AF at
3 months correlated with the degree of wall enhancement
with >13% injury in the LA predicting freedom from AF
[38]. A subsequent study by Badger et al. confirmed these
findings that higher total LA scar correlated well with
reduced AF recurrence. In addition, they demonstrated
that DE-MRI integration could be used to identify the
location of gaps or recovery in previous ablation scar that
could be potentially used as targets in repeat ablation
procedures [39]. Further studies will need to be done to
investigate the clinical application of DE-MRI in guiding
AF ablation procedures and how this will impact clinical
outcomes.
6 Conclusion
Fusion of imaging technologies or image integration has
been shown to be a highly valuable tool in performing
circumferential AF ablation. Although there have been
mixed results, several studies have reported improved
long-term outcomes, and this approach is now relied on
around the world at many centers to guide AF ablation.
The next step forward is to employ a technique that
allows the myocardial scar to be co-registered with a
surface shell to facilitate the ablation of ventricular
tachycardia and also atrial fibrillation. Several centers,
including ours, now routinely register scar images to
guide VT ablation and we anticipate that this approach
will rapidly spread to other centers, and the final step
will be to use this approach to guide AF ablation,
especially in patients who are undergoing repeat AF
ablation procedures.
Fig. 6 MRI of the left atrium and ventricle. Mid-myocardial scar in
the ventricular septum is shown (white defect ) [36]
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References
1. Gepstein, L., Hayam, G., & Ben-Haim, S. A. (1997). A novel
method for nonfluoroscopic catheter-based electroanatomical
mapping of the heart. In vitro and in vivo accuracy results.
Circulation, 95(6), 1611 – 1622.
2. Peters, N. S., Jackman, W. M., Schilling, R. J., Beatty, G., &
Davies, D. W. (1997). Human left ventricular endocardial
activation mapping using a novel noncontact catheter. Circulation,95, 1658 – 1660.
3. Novak, P., Guerra, P., Thibault, B., & Macle, L. (2004). Utility of
a nonfluoroscopic navigation system for pulmonary vein isolation.
Journal of Cardiovascular Electrophysiology, 15 , 967.
4. Khaykin, Y., Oosthuizen, R., Zarnett, L., Wulffhart, Z. A.,
Whaley, B., Hill, C., et al. (2011). CARTO-guided vs. NavX-
guided pulmonary vein antrum isolation and pulmonary vein
antrum isolation performed without 3-D mapping: effect of the 3-
D mapping system on procedure duration and fluoroscopy time.
Journal of Interventional Cardiac Electrophysiology, 30(3), 233 –
240.
5. Scaglione, M., Biasco, L., Caponi, D., Anselmino, M., Negro, A., Di
Donna, P., et al. (2011). Visualization of multiple catheters with
electroanatomical mapping reduces X-ray exposure during atrial
fibrillation ablation. Europace, 13(7), 955 – 9626. Jais, P., Haissaguerre, M., Shah, D. C., et al. (1997). A focal
source of atrial fibrillation treated by discrete radiofrequency
ablation. Circulation, 95, 572 – 576.
7. Haissaguerre, M., Jais, P., Shah, D. C., et al. (1998). Spontaneous
initiation of atrial fibrillation by ectopic beats originating in the
pulmonary veins. The New England Journal of Medicine, 339,
659 – 666.
8. Chen, S. A., Hsieh, M. H., Tai, C. T., et al. (1999). Initiation of
atrial fibrillation by ectopic beats originating from the pulmonary
veins: electrophysiological characteristics, pharmacological
responses, and effects of radiofrequency ablation. Circulation,
100, 1879 – 1886.
9. Robbins, I. M., Colvin, E. V., Doyle, T. P., Kemp, W. E., Loyd, J.
E., McMahon, W. S., et al. (1998). Pulmonary vein stenosis after
catheter ablation of atrial fibrillation. Circulation, 98(17), 1769 –
1775.
10. Kato, R., Lickfett, L., Meininger, G., Dickfeld, T., Wu, R., Juang,
G., et al. (2003). Pulmonary vein anatomy in patients undergoing
catheter ablation of atrial fibrillation. Lessons learned by use of
the magnetic resonance imaging. Circulation, 107 , 2004 – 2010.
11. Pappone, C., Rosanio, S., Augello, G., et al. (2003). Mortality,
morbidity, and quality of life after circumferential pulmonary vein
ablation for atrial fibrillation: outcomes from a controlled non-
randomized long-term study. Journal of the American College of
Cardiology, 42, 185 – 197.
12. Solomon, S. B., Dickfeld, T., & Calkins, H. (2003). Real-time
cardiac catheter navigation on three-dimensional CT images.
Journal of Interventional Cardiac Electrophysiology, 8(1), 27 – 36.
13. Dickfeld, T., Calkins, H., Zviman, M., Kato, R., Meininger, G.,
Lickfett, L., et al. (2003). Anatomic stereotactic catheter ablation
on three-dimensional magnetic resonance images in real time.
Circulation, 108(19), 2407 – 2413.
14. Dickfeld, T., Calkins, H., Bradley, D., & Solomon, S. B. (2005).
Stereotactic catheter navigation using magnetic resonance image
integration in the human heart. Heart Rhythm, 2(4), 413 – 415.
15. Dong, J., Calkins, H., Solomon, S. B., Lai, S., Dalal, D., Lardo, A.
C., et al. (2006). Integrated electroanatomic mapping with three-
dimensional computed tomographic images for real-time guided
ablations. Circulation, 113(2), 186 – 194.
16. Dong, J., Dickfeld, T., Lamiy, S. Z., & Calkins, H. (2005). Heart
Rhythm. Catheter ablation of atrial fibrillation guided by
registered computed tomographic image of the atrium. Heart
Rhythm, 2(9), 1021 – 1022.
17. Dong, J., Dickfeld, T., Dalal, D., Cheema, A., Vasamreddy, C. R.,
Henrikson, C. A., et al. (2006). Initial experience in the use of
integrated electroanatomic mapping with three-dimensional MR/
CT images to guide catheter ablation of atrial fibrillation. Journal
of Cardiovascular Electrophysiology, 17 (5), 459 – 466.
18. Dong, J., Dalal, D., Scherr, D., Cheema, A., Nazarian, S.,
Bilchick, K., et al. (2007). Impact of heart rhythm status on
registration accuracy of the left atrium for catheter ablation of atrial fibrillation. Journal of Cardiovascular Electrophysiology, 18
(12), 1269 – 1276.
19. Khaykin, Y., Klemm, O., & Verma, A. (2008). First human
experience with real-time integration of intracardiac echocardiog-
raphy and 3D electroanatomical imaging to guide right free wall
accessory pathway ablation. Europace, 10, 116 – 117.
20. Zhong, H., Lacomis, J. M., & Schwartzman, D. (2007). On the
accuracy of CartoMerge for guiding posterior left atrial ablation in
man. Heart Rhythm, 4(5), 595 – 602.
21. Noseworthy, P. A., Malchano, Z. J., Ahmed, J., Holmvang, G.,
Ruskin, J. N., & Reddy, V. Y. (2005). The impact of respiration on
left atrial and pulmonary venous anatomy: implications for image-
guided intervention. Heart Rhythm, 2, 1173 – 1178.
22. Heist, E. K., Chevalier, J., Holmvang, G., Singh, J. P., Ellinor, P.
T., Milan, D. J., et al. (2006). Factors affecting error in integrationof electroanatomic mapping with CT and MR imaging during
catheter ablation of atrial fibrillation. Journal of Interventional
Cardiac Electrophysiology, 17 (1), 21 – 27.
23. Dickfeld, T., Calkins, H., Zviman, M., Kato, R., Meininger, G.,
Lickfett, L., et al. (2003). Anatomic stereotactic catheter ablation
on three-dimensional magnetic resonance images in real time.
Circulation, 108(19), 2407 – 2413.
24. Nazarian, S., Kolandaivelu, A., Zviman, M. M., Meininger, G. R.,
Kato, R., Susil, R. C., et al. (2008). Feasibility of real-time magnetic
resonance imaging for catheter guidance in electrophysiology
studies. Circulation, 118(3), 223 – 229.
25. Okumura, Y., Henz, B., Johnson, S., Bunch, T., O'Brien, C.,
Hodge, D., et al. (2008). Three-dimensional ultrasound for image-
guided mapping and intervention: methods, quantitative valida-
tion, and clinical feasibility of a novel multimodality image
mapping system. Circulation Arrhythmia, 1, 110 – 119.
26. Martinek, M., Nesser, H. J., Aichinger, J., Boehm, G., &
Purerfellner, H. (2007). Impact of integration of multislice
computed tomography imaging into three-dimensional electro-
anatomic mapping on clinical outcomes, safety, and efficacy using
radiofrequency ablation for atrial fibrillation. Pacing and Clinical
Electrophysiology, 30(10), 1215 – 1223.
27. Della Bella, P., Fassini, G., Cireddu, M., Riva, S., Carbucicchio,
C., Giraldi, F., et al. (2009). Image integration-guided catheter
ablation of atrial fibrillation: a prospective randomized study.
Journal of Cardiovascular Electrophysiology, 20(3), 258 – 265.
28. Bertaglia, E., Bella, P. D., Tondo, C., Proclemer, A., Bottoni, N.,
De Ponti, R., et al. (2009). Image integration increases efficacy of
paroxysmal atrial fibrillation catheter ablation: results from the
CartoMerge Italian Registry. Europace, 11(8), 1004 – 1010.
29. Hunter, R. J., Ginks, M., Ang, R., Diab, I., Goromonzi, F. C.,
Page, S., et al. (2010). Impact of variant pulmonary vein anatomy
and image integration on long-term outcome after catheter
ablation for atrial fibrillation. Europace, 12(12), 1691 – 1697.
30. Kistler, P., Rajappan, K., Harris, S., Earley, M. J., Richmond, L.,
Sporton, S. C., et al. (2008). The impact of image integration on
catheter ablation of atrial fibrillation using electroanatomic
mapping: a prospective randomised study. European Heart
Journal, 29(24), 3029 – 3036.
31. Caponi, D., Corleto, A., Scaglione, M., Blandino, A., Biasco, L.,
Cristoforetti, Y., et al. (2010). Ablation of atrial fibrillation: does
202 J Interv Card Electrophysiol (2011) 32:195 – 203
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the addition of three-dimensional magnetic resonance imaging of
the left atrium to electroanatomic mapping improve the clinical
outcome?: A randomized comparison of Carto-Merge vs. Carto-
XP three-dimensional mapping ablation in patients with paroxys-
mal and persistent atrial fibrillation. Europace, 12(8), 1098 – 1104.
32. Tang, K., Ma, J., Zhang, S., Zhang, J. Y., Wei, Y. D., Chen, Y. Q.,
et al. (2008). A randomized prospective comparison of Carto-
Merge and CartoXP to guide circumferential pulmonary vein
isolation for the treatment of paroxysmal atrial fibrillation.
Chinese Medical Journal, 121, 508 – 512.33. Dickfeld, T., Lei, P., Dilsizian,V., Jeudy, J., Dong, J., Voudouris, A., et
al. (2008). Integration of three-dimensional scar maps for ventricular
tachycardia ablation with positron emission tomography-computed
tomography. JACC. Cardiovascular Imaging, 1(1), 73 – 82.
34. Tian, J., Smith, M. F., Jeudy, J., & Dickfeld, T. (2009).
Multimodality fusion imaging using delayed-enhanced cardiac
magnetic resonance imaging, computed tomography, positron
emission tomography, and real-time intracardiac echocardiography
to guide ventricular tachycardia ablation in implantable cardioverter –
defibrillator patients. Heart Rhythm, 6 (6), 825 – 828.
35. Tian, J., Jeudy, J., Smith, M. F., Jimenez, A., Yin, X., Bruce, P. A.,
et al. (2010). Three-dimensional contrast-enhanced multidetector
CT for anatomic, dynamic, and perfusion characterization of
abnormal myocardium to guide ventricular tachycardia ablations.
Circulation. Arrhythmia and Electrophysiology, 3(5), 496 – 504.
36. Nazarian, S., Bluemke, D. A., Lardo, A. C., Zviman, M. M.,
Watkins, S. P., Dickfeld, T. L., et al. (2005). Magnetic resonance
assessment of the substrate for inducible ventricular tachycardia in
nonischemic cardiomyopathy. Circulation, 112(18), 2821 – 2825.
37. Peters, D. C., Wylie, J. V., Hauser, T. H., et al. (2007). Detection
of pulmonary vein and left atrial scar after catheter ablation with
three-dimensional navigator-gated delayed enhancement MR imaging: initial experience. Radiology, 243, 690 – 695.
38. McGann, C. J., Kholmovski, E. G., Oakes, R. S., Blauer, J. J.,
Daccarett, M., Segerson, N., et al. (2008). New magnetic
resonance imaging-based method for defining the extent of left
atrial wall injury after the ablation of atrial fibrillation. Journal of
the American College of Cardiology, 52, 1263 – 1271.
39. Badger, T. J., Daccarett, M., Akoum, N. W., Adjei-Poku, Y. A.,
Burgon, N. S., Haslam, T. S., et al. (2010). Evaluation of left atrial
lesions after initial and repeat atrial fibrillation ablation: lessons
learned from delayed-enhancement MRI in repeat ablation
procedures. Circulation. Arrhythmia and Electrophysiology, 3(3),
249 – 259.
J Interv Card Electrophysiol (2011) 32:195 – 203 203