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Noncontact mapping using the Endocardial Solutions EnSite 3000 system in flutter ablation at patients with
right aneurismal atrium
NONCONTACT MAPPING USING THE ENDOCARDIAL
SOLUTIONS ENSITE 3000 SYSTEM IN FLUTTER ABLATION
AT PATIENTS WITH RIGHT ANEURISMAL ATRIUM
O. Nutu¹, L.Chiriac², G.Cristian², I.Tintoiu², M.Gheorghe³
¹Hopital Foch Paris, ²Army’s Clinical Center for Cardiovascular Disease,
³University Titu Maiorescu Bucharest
Abstract – The aim of the Study was to identify
clinical
electrocardiographic
and
echocardiographic characteristics of atrial flutter
radiofrequency ablation at patients with
aneurismal dilated atrium using noncontact
mapping.
Results show that the majority of radio frequency
applications in patients with aneurismal dilated
atrium was situated in cava tricuspid isthmus,
near inferior vena cava evidentiating that
noncontact mapping is a safe method in dilated
cava tricuspid isthmus
Key words – Atrial flutter, radiofrequency
Catheter ablation, noncontact mapping, EnSite
3000 System
noncontact mapping.The non-contact mapping
system consists of a catheter and a powerful
computer. The non-contact catheter, which has many
sensing electrodes, is put in a stationary location —
often in the center of the heart chamber. The catheter
acts like a miniature radio antenna, receiving signals
from all around the heart chamber and relaying them
to the computer. The computer processes the signals
and displays the recorded information on a threedimensional map of the heart chamber. ith the noncontact mapping system your we
create a
computerized model of the heart and record its
electrical activation. This three-dimensional model
shows your the source of arrhythmia and guides a
therapeutic catheter to the arrhythmia source¹.
Methods
Introduction
Arrhythmias affect millions of people worldwide
and can result in heartbeats that are either too slow,
erratic, or too fast. These arrhythmias cause the
blood to pump inefficiently, resulting in dizziness,
fatigue, or other symptoms. Fast heartbeats cause the
blood to pump inefficiently. There are two types of
fast heartbeats: focal arrhythmias and reentrant
arrhythmias. In focal arrhythmia (such as focal
tachycardia), a site other than the SA node is
initiating rhythms, which may cause the heart to beat
faster. In reentrant arrhythmias (such as atrial
flutter), the electrical signals circulate repetitively in
a closed circuit. EnSite 3000 System is a diagnostic
tool to help physicians analyze electrical signals in
the heart and facilitate catheter placement for
therapeutic ablation. Typical atrial flutter in 15
patients, with aneurismal dilated atrium was
mapping
and
treated
by
ablation
in
Electrophysiology Laboratory from Army’s Clinic
Emergency Center for Cardiovascular Disease. The
aim of this study was to identify clinical,
electrocardiographic
and
echocardiographic
characteristics of atrial flutter underwent catheter
ablation, to report the localization of the ablation
line in patients with aneurismal dilated atrium using
The study included 15 consecutive symptomatic
patients (age 61 ± 13 years; 1 woman) with common
counterclockwise atrial flutter were refereed for
catheter ablation of the inferior vena cava – tricuspid
isthmus. Some degree of sedation was used in
apprehensive patients. Antiarrhythmic drugs was
usually stopped prior these studies. In selected cases,
other cardioactive drugs was administrated for
nonarrhythmic cardiovascular problems such as
hypertension, angina, and heart failure. The typical
electrode catheters used was multipolar (sizes
varying from 4 to 8 F). Catheters was inserted via
femoral veins. After using local anesthesia, a guide
wire is inserted percutaneously through a needle,
and a sheath is advanced over the guide wire, then
guided fluoroscopically through the sheath to the
right atrial atrium.. Heparinization was administrated
- 1000 units per hour to keep ACT (Activated
clothing time) at 300s.
Mapping
was
performed
using
only
noncontactmapping catheterThe EnSite catheter uses
a balloon design with a 64-electrode array arranged
over the outside of the balloon. This balloon is
positioned in the center of the chamber and does not
come in contact with the walls of the chamber being
The Romanian Review Precision Mechanics, Optics & Mecatronics, 2008 (18), No. 34
55
Noncontact mapping using the Endocardial Solutions EnSite 3000 system in flutter ablation at patients with
right aneurismal atrium
mapped. Using data from the 64-electrode array
catheter, the computer uses sophisticated algorithms
to compute an inverse solution to determine the
activation sequence on the endocardial surface. Data
from all points in the chamber are acquired
simultaneously. To create a map, the balloon
catheter (has current 9.5-F lumen).was positioned in
the lower third of the right atrial atrium with the
center of the ballon above the level of the coronary
sinus ostium and deployed. A conventional (7F
standard catheter with a 4 mm tip) deflectable
catheter was also positioned in the chamber and used
to collect geometry information. A 5-kHz signal was
emitted from the tip electrode of the conventional
catheter, and the computer analyzes this signal to
determine the position of the roving catheter relative
to the position of the balloon. The roving catheter is
moved throughout the chamber, and the location
information is collected by the system². Using this
information, the computer creates a model, called a
convex hull, of the chamber during dastole. (Fig.1)
Fig.1 Three dimensional map of the dilated right atrium using noncontact mapping
Once the electrode catheters are placed
appropriately, the connections are made via a
junction box and isolation units to prevent excess
current in the event of random electrical surges. All
of the electrograms are displayed simultaneously on
a multi-channel oscilloscopic recorder. In addition to
the intracardiac signals, several unfiltered surface
electrocardiographic leads (i.e., X, Y, and Z or leads
I, II, or aVF and V1) are recorded. To reduce the
noise generated with the low-frequency signals, the
usual filtering frequency for intracardiac signals is
between 30 and 40 Hz for the high-pass and 500 Hz
for the low-pass filters. Although appropriately
placed electrode catheters will record desired signals
at any filtering frequency, filter settings between 30
to 40 and 500 Hz are best suited for sharp
intracardiac signals such as those from the His
bundle and accessorypathways . Undesirable lowfrequency signals can be reduced by a high-pass
filter setting of more than 50 to 100 Hz. On the other
hand, 60-cycle interference can be eliminated with a
low-pass filter setting at 50 Hz. Alteration in the
high-bandpass filter for surface electrocardiography
can markedly alter the scalar electrocardiographic
morphology. Amplification is frequently necessary
to identify desirable signals from the specialized
conduction system. This can lead to superimposition
of the larger myocardial signals on various
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electrocardiographic tracings. In most recording
equipment, however, limiting filters allow the
adjustment of amplitude limits.The intracardiac
electrocardiographic tracings was timing of electric
circuit and determine the direction of impulse
propagation. To acquire true local electrical activity,
a bipolar electrogram with an interelectrode distance
of less than 1 cm is desirable. When unipolar
electrograms are obtained, a rapid intrinsic
deflection will identify a point of local activation.
The data acquisition process was performed
automatically by the system, and all data for the
entire chamber are acquired simultaneously. A three
dimensional map of the right atrium was created.
Major landmarks were recorded and labeled on the
EnSite map. The area of interest was identified using
the three dimensional isopotential map in
combination with surface ECG and computed
electrograms (coronary sinus, superior vena cava,
inferior vena cava and tricuspide valve anullus)
Noncontact mapping with the EnSite 3000 System
allows single-beat mapping (Fig.2). The inversesolution computations are performed by the system
in real time and projected on to the surface of the
convex-hull model, creating a 3D model showing
the activation sequence within the chamber.
Following this, the segment must be analyzed by the
operator to find the early activation or vulnerable
The Romanian Review Precision Mechanics, Optics & Mecatronics, 2008 (18), No. 34
Noncontact mapping using the Endocardial Solutions EnSite 3000 system in flutter ablation at patients with
right aneurismal atrium
region of the reentry circuit. The locator technology
that was used to collect the geometry information for
the convex hull can then be used to guide an ablation
catheter to the proper location in the heart. Because
data from the entire chamber are collected
simultaneously with the EnSite 3000 system, it can
be used to map patients that was hemodynamically
stable³.
Fig. 2 Noncontact mapping with the EnSite 3000 System allows single-beat mapping
Measurements of right atrium were obtained using
the two-dimensional echocardiography and EnSite
3000 noncontact mapping system when a detailed
geometry of the chamber was reconstructed. The
right atrial long axis was measured from the junction
of the tricuspid valve and the intraventricular septum
to the roof of the right atrium. The right atrial short
axis was measured as the maximum distance
between the inner borders of the interatrial septum
and the free wall of the right atrium. The septal
isthmus length was measured as the distance
between the junction of the tricuspid septal leaflet
with the intraventricular septum and the coronary
sinus ostium. The inferior vena cava – tricuspid
isthmus length was measured as the distance from
the lateral border of the tricuspid annulus to the
inferior vena cava origin.
Data are expressed as mean ± SD. A probability
value of p<0,05, was accepted as statistically
significant. Several variables including anatomical
atrial data, were tested: age, gender, the type of atrial
flutter (chronic vs. paroxysmal), structural heart
disease, left ventricular ejection fraction (%), cavatricuspid isthmus dimension (mm), septal isthmus
dimension (mm), right atrial size (mm), number of
radiofrequency applications (± SD), mitral
regurgitation (II, III or IV grade), flutter cycle length
(ms), A-wave velocity (cm/s), E-wave velocity
(cm/s), E/A, right atrial area (cm²).
After geometry was obtained, a short segment of
atrial flutter was recorded. The majority of patients
were presented in the lab in atrial flutter so induction
of the arrhythmia was not necessary. The
endocardial activation map demonstrated
a
counterclockwise istmus dependent flutter. Using
the EnGuide location signal, the ablation catheter
was guided to the isthmus region. Continuos lesions
were created using ablation catheter. (Fig.3).
The Romanian Review Precision Mechanics, Optics & Mecatronics, 2008 (18), No. 34
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Noncontact mapping using the Endocardial Solutions EnSite 3000 system in flutter ablation at patients with
right aneurismal atrium
Fig.3. Radiofrequency ablation lesions delivered at the “gap” site in a dilated cavo-tricuspid isthmus , near
inferior vena cava
septum near coronary sinus.
Results
The mean number of radiofrequency application
Successful isthmus ablation with bi-directional
was 17 ± 9 (range from 6 to 33), septal isthmus 27 ±
conduction block eliminating right atrial flutter was
4 mm and cava –tricuspid isthmus 45 ± 9 mm. All
achieved in all patients. To confirm the absence of
patients with remained free of atrial flutter with an
conduction across the isthmus following ablation,
average follow-up for 6,4 months. Mean total
atrial pacing was done from the proximal coronary
fluoroscopy time was 39 min. Of the patients with
sinus (CS). No conduction was observed across the
dilated atrium, undergoing ablation of common
delayed conduction. Next, to confirm bi-directional
counterclockwise atrial flutter, early atrial
block across the isthmus, pacing was performed in
fibrillation wasdocumented in 1 patient, presented
the lower lateral part of the right atrium showing
arrhythmogenic gaps that was corrected afterwards.
very delayed activation in the lower interatrial
Table 1. Clinical, electrocardiographic and echocardiographic characteristics
Atrial flutter (n=15)
Age y ± SD
61 ± 13
Type of atrial flutter (chronic vs. paroxysmal) (%)
80
Structural heart disease (%)
100
Radiofrequency applications (%)
17 ± 9
Right atrial size (mm)
61 ± 8
Right atrial area (cm²)
34 ± 8
Septal isthmus dimension (mm)
26 ± 8
Cava-tricuspid isthmus dimension (mm)
44 ± 9
A-wave velocity (cm/s)
0,53 ± 0,16
E-wave velocity (cm/s)
0,8 ± 2
E/A
1,8 ± 0,9
Left ventricular ejection fraction (%)
44,2 ± 13
Mitral regurgitation (%)
60
Atrial flutter cycle length (ms)
270 ± 40
Preablation history of atrial fibrillation (%)
80
Fluoroscopy time (min)
39 ± 12
Conclusions
The
majority of sequentional radiofrequency
applications in patients with aneurismal dilataed
atrium was situated in cava tricuspid isthmus, in low
region near inferior vena cava. Noncontact mapping
has been shown to be an safe method for
demonstrating the complete circuit of typical atrial
flutter, in dilated cavotricuspid isthmus. The EnSite
3000 system provides a clear, accurate view of
chamber anatomy and activation. The clinician can
view and analyse aarrhythmia conductionnand
precisely label anatomic and ablation sites.
Confirmation of therapy is simplified with the
dynamic isopotential maps and computed
electrograms.
These mapping systems, both of which are relatively
new, provide electrophysiologists with new tools for
diagnosing and treating what are often complex
arrhythmias. They make use of state-ofthe-art
technology to accomplish their objectives and
improve the state of the art in arrhythmia
management. Because these technologies are so
58
new, further enhancements can be expected that will
further the usefulness of advanced mapping
techniques in the practice of electrophysiology.
Bibliography
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4.
Chad E. and colab. - Radiofrequency Catheter
Ablation Using Non-Contact Mapping for
Inappropriate Sinus Tachycardia - Journal of
Interventional
Cardiac
Electrophysiology,
Volume 10, Number 2 / April, 2004,
Thomas Pauland colab. - Non-contact mapping
and ablation of tachycardia originating in the
right ventricular outflow tract - Cardiology in
the Young 2002, 12 : 294-297,
Reginald Liew and colab.- Use of non-contact
mapping in the treatment of right atrial
tachycardias in patients with and without
congenital heart disease - Europace 2008
10(8):972-981;
HurstTechniques
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Intracardiac
Electrophysiologic Studies – The Heart , 12e
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