Effect of Isthmus Anatomy and Ablation Catheter on
Radiofrequency Catheter Ablation of the
Cavotricuspid Isthmus
Antoine Da Costa, MD; Emmanuel Faure, MD; Jérôme Thévenin, MD; Marc Messier, PhD;
Samuel Bernard, RN; Kihel Abdel, RN; Christophe Robin, MD;
Cécile Romeyer, MD; Karl Isaaz, MD, FESC
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Background—Cavotricuspid isthmus (CTI) characteristics are rarely documented when comparing catheters in radiofrequency ablation (RFA) of atrial flutter (AFL). Our objectives were (1) to evaluate the impact of CTI morphology and
length on ablation procedures and (2) to compare the efficacy of an 8-mm-tip catheter with an irrigated cooled-tip RFA
in the subgroup presumed to be more difficult to treat (with a long CTI, ⬎35 mm).
Methods and Results—Over a period of 17 months, 185 patients accepted the protocol and underwent an isthmogram in
preparation for RFA. Groups were classified according to CTI length and CTI morphology. RFA was performed with
an 8-mm-tip catheter for patients with a short CTI, ⱕ35 mm (n⫽123), whereas randomization between an 8-mm-tip and
a cooled-tip catheter applied to patients with a longer CTI, ⬎35 mm (n⫽62). For long CTI, 32 patients were assigned
to an 8-mm catheter and 30 patients to the cooled-tip RFA ablation group. In this subset, RF application (18.2⫾17 versus
19⫾13 minutes) and x-ray exposure (20.8⫾18 versus 18⫾13 minutes) did not differ between the 8-mm-tip and the
cooled-tip procedures. Number of applications (9.9⫾11 versus 18.6⫾15 minutes; P⬍0.0001) and x-ray exposure
(11.7⫾11 versus 19.5⫾16 minutes, P⫽0.0001) differed significantly between patients with short and long CTIs.
Patients with short and straight CTIs required 3 times fewer RFA applications and shorter x-ray exposure compared with
other CTI morphologies (pouch-like recesses and concave characteristics).
Conclusions—The number of RF applications required for a complete isthmus block in long CTIs is not influenced by the
choice between an 8-mm or cooled-tip catheter. Procedure parameters, however, are significantly influenced by CTI
length and morphology. Pouch-like recesses and concave characteristics account for much longer ablation times at all
CTI lengths. (Circulation. 2004;110:1030-1035.)
Key Words: atrial flutter 䡲 catheter ablation 䡲 angiography 䡲 structure
R
adiofrequency catheter ablation (RFA) of the cavotricuspid isthmus– dependent atrial flutter1,2 (CTI-AFL) is the
treatment of choice when its high efficacy is considered.3– 6
Despite a high success rate, ablation of the CTI can be
extremely difficult in some patients.7,8 The vast span seen in
ablations (1 to 30 or more RF applications) must thus reflect
phenomena as yet unqualified. Recent right atrial angiographic studies have demonstrated a highly variable isthmus
anatomy with various configurations and topologies.9,10
These anatomic aspects seem to lead to more difficult
ablation sessions10: one study correlated 100 isthmus anatomies with number of applications and reached significance
(P⫽0.05 exactly), correlating median RF applications to
concave isthmi. A smaller study with 40 patients reported a
linear relationship between isthmus length and number of
applications.11 Although irrigated and 8-mm-tip catheters
were found to be more effective and as safe as conventional 4-mm-tip catheters for AFL-RFA,12,13 the studies
comparing these were unfortunately not randomized or
showed debatable results.14,15 There was thus a need for a
prospective randomized comparison of the efficacy and
safety of cooled-tip and 8-mm-tip catheters while considering the influence of CTI anatomy and length on ablation
success.10,11 The aim of this prospective study was 2-fold,
as follows: (1) to evaluate the impact of CTI morphology
and length on AFL-RFA procedures and (2) to randomly
compare the efficacy and safety of an 8-mm-tip catheter
with those of an irrigated cooled-tip catheter for RFA in a
subgroup of patients with presumedly more difficult,
⬎35-mm-long CTIs.
Received October 1, 2003; de novo received December 4, 2003; revision received March 19, 2004; accepted March 29, 2004.
From the University Hospital Jean Monnet, Division of Cardiology, Saint-Etienne, France, and Bakken Research Center, Maastricht, the Netherlands
(M.M.).
Presented in part at the 52nd Annual Scientific Session of the American College of Cardiology, Chicago, Ill, March 30 –April 2, 2003, and published
in abstract form (J Am Coll Cardiol. 2003;41(suppl A):1042–1043).
Correspondence to Dr Antoine Da Costa, Service de Cardiologie, Hôpital Nord, Centre Hospitalier Universitaire de Saint-Etienne, 42 055 Saint-Etienne
Cedex 2, France. E-mail [email protected]
© 2004 American Heart Association, Inc.
Circulation is available at http://www.circulationaha.org
DOI: 10.1161/01.CIR.0000139845.40818.75
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Da Costa et al
Atrial Flutter and Ablation
1031
Methods
Study Population
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The study was approved by the Institutional Research Board of the
Saint-Etienne Hospital and by its Ethics Committee in October 2001.
From November 2001 to April 2003, there were 219 consecutive
symptomatic patients with counterclockwise, typical AFL referred
for RFA who agreed to sign an informed consent. AFL was
diagnosed when (1) the surface ECG showed flutter waves that were
predominantly negative in leads II, III, and aVF and positive in lead
V1, with a regular atrial rate between 240 and 340 bpm; (2) the
intracardiac electrogram displayed the following activation sequence: high right atrium then low right atrium, a counterclockwise
inferior vena cava (IVC)–tricuspid isthmus activation sequence
followed by left atrial activation established with a dodecapolar lead;
and (3) an isthmus participation in the arrhythmic circuit as demonstrated by entrainment maneuvers (concealed entrainment in the
isthmus). Exclusion criteria were as follows: (1) absence of informed
patient consent; (2) iodine contraindication (allergy, kidney failure
with creatinine ⱖ150 ␮mol/L, or lithium treatment); (3) age ⬍18
years; (4) inability to catheterize (vena caval clip); (5) AFL recurrence after a previous ablation session; and (6) pregnancy.
Over the 17-month inclusion period, 219 consecutive patients with
AFL were considered eligible. Thirty-four patients were excluded,
and the remaining 185 (32 women; 67⫾11 years old; range, 20 to 88
years) signed an informed consent and underwent an isthmogram in
preparation for RFA.
Electrophysiological Testing, IVC–Tricuspid
Isthmus Mapping, and AFL Ablation
Electrophysiological Study
Patients were taken off antiarrhythmic drugs for at least 5 half-lives
(with the exception of amiodarone), then fasted to undergo an
electrophysiological study. Two catheters were introduced through
the right femoral vein into the right atrium. A 6F quadripolar catheter
with an interelectrode distance of 5 mm (Bard Electrophysiology)
was advanced to the His-bundle position, then a dodecapolar catheter
with a 5-mm bipolar separation (Bard) was positioned in the
coronary sinus. The distal tip was placed in the coronary sinus
ostium as electrodes 1,2 (H1). Electrodes 3,4 (H2), 5,6 (H3), and 7,8
(H4) were located close to the IVC–tricuspid isthmus, whereas
electrodes 9,10 (H5) and 11,12 (H6) recorded the low and high right
atrial activation, respectively. Surface ECGs (leads I, II, III, and V1)
were filtered through a 1- to 500-Hz bandpass filter, whereas bipolar
intracardiac electrograms were filtered at 30 to 500 Hz and amplified
at high gain (0.1 mV/cm). All measurements were performed with
the Cardiolab system (Prucka Engineering). A programmable stimulator (Medtronic) with a 2-ms output pulse width set at 4 times the
threshold amplitude was used.
Right Atrial Angiography
Biplane angiography was performed after mapping and shortly
before RF energy delivery. An isthmogram was performed by
positioning a 5F pigtail catheter in the IVC just at the level of the
splenic and hepatic veins.9,10 Contrast solution was injected during 3
to 5 seconds for a total of 50 cm3 in each patient. The angiograms
were digitally acquired, thus allowing replay and storage of right
anterior oblique (RAO) frames as reference during the subsequent
ablation. Measurements were calibrated by interelectrode spaces
projecting perpendicular to the given cine view. The length of the
CTI was obtained at 25° in the RAO projection between the IVC and
the lower hinge point of the tricuspid valve (points A and B in Figure
1). CTI length measurements and morphology analysis were made
on the latest atrial diastolic frame (confirmed by the opening of the
tricuspid valve in the next frame). The perpendicular distance
between the line connecting A and B and the deepest point of the
isthmus was quantified. If a single injection did not allow a clear
delineation of the CTI, the angiogram was repeated. Considering
previous works,9,10 patient groups were classified by CTI length
(short, ⱕ35 mm, or long, ⬎35 mm) and further subdivided by CTI
Figure 1. A, Short, straight isthmus. Angiographic visualization
of isthmus in RAO during contrast injection. Isthmus width measured between IVC (A) and lower hinge point of tricuspid valve
(B). Isthmus with straight appearance (maximal distance
between line A–B and isthmus is ⱕ2 mm) with an average width
of 26.8 mm. B, Short, pouch-like recess isthmus. Flat vestibular
structure 15.8 mm long against tricuspid annulus and a pouchlike recess 14.1 mm long near IVC. Pouch-like recess is 5.1 mm
deep.
morphology as straight, concave, or presence of a pouch-like recess
(Figures 1 and 2). The straight aspect was defined as a maximal distance
between A and B, with an isthmus depth ⱕ2 mm. An independent
operator performed all measurements and analyses (S.B.).
Catheter Ablation
Catheter randomization was performed (for long CTIs) after right
atrial angiography. An RF current application (unmodulated, sine
wave) was delivered in the unipolar mode between the distal ablation
catheter tip and a cutaneous patch electrode placed over the left
scapula with a maximal target temperature of 60°C for 60 seconds
for conventional ablation (8-mm-tip catheter). RF delivery by the
same operator (A.D.C.) was applied point-by-point and was started
at the ventricular aspect of the tricuspid annulus when a stable
1032
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August 31, 2004
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Saline (0.9%) was infused through the irrigated catheter with a Geini
Imed pump (battery-powered to avoid 50-Hz line noise) at a rate of
17 mL/min during RFA delivery. Between applications, a flow rate
of 3 mL/min was used to maintain patency.
When more than 30 RFA applications (cumulatively 1800 seconds) were unsuccessful, short CTIs switched to cooled-tip ablation,
and long CTIs crossed over to the alternative catheter.
The procedure end point was defined as a complete bidirectional
isthmus block described elsewhere.3,4 Reversal of the right atrial
depolarization sequence was established by a complete cavotricuspid
map using a multipolar mapping catheter straddling the line of block5
and by recording widely separated local double potentials along the
ablation line during atrial pacing.16,17 When signs of conduction
block were observed during RF application with proximal coronary
sinus pacing, 1 extra RF application lasting 1 minute was performed
at that site. Pacing was performed at a cycle length of 600 ms from
the proximal coronary sinus and the low lateral right atrium. The
status of the bidirectional block was assessed continuously over the
30-minute period after bidirectional block occurrence. Thirty minutes after the bidirectional block was validated,18 all patients underwent a postablation control by burst pacing at cycle lengths as short
as 180 ms. On occasion, conduction resumed after ablation, which
reinitiated a complete RFA sequence until the bidirectional block
could be observed again, resetting the 30-minute waiting period. A
cumulative time of RF delivery was recorded, and fluoroscopy time
was calculated as total fluoroscopy time used for catheter positioning
and RFA, including time to proof of bidirectional block. Venous
thromboses were systematically prevented by subcutaneous lowmolecular-weight heparin for 7 days.
Follow-Up
After catheter ablation, all patients underwent continuous ECG
monitoring for at least 24 hours before hospital discharge. Cumulative risk of atrial fibrillation was determined by outpatient follow-up
and on recurring symptoms or palpitations. The outpatient follow-up
was performed by the referring cardiologist and by the medical
practitioner. ECGs were programmed at each consultation, at the end
of follow-up, and on recurring symptoms.
Statistical Analysis
Summary values are given ⫾SD. The differences among groups
were analyzed by ANOVA. A probability value of P⬍0.05 was
accepted as statistically significant. The number of applications,
procedure duration, and x-ray exposure were analyzed on an
intention-to-treat basis. The mean follow-up for the entire population
was evaluated by use of the Kaplan-Meier method and by the
log-rank test.
Results
Figure 2. A, Long, straight isthmus aspect; isthmus width is
36 mm. B, Long, concave isthmus aspect: average width of
36.3 mm and depth of 3.8 mm.
electrogram with a small atrial and large ventricular amplitude was
observed. The catheter was withdrawn after each application, under
fluoroscopic guidance, to produce a linear and continuous lesion
until the IVC was reached. RF delivery was applied until a
bidirectional isthmus block could be obtained. For all measurements,
the filter was set at from 30 to 500 Hz.
An 8F quadripolar deflectable catheter with an 8-mm-tip electrode
(Boston EP Technologies) was used for RFA in the group with short
CTIs (ⱕ35 mm), whereas patients with long CTIs, ⬎35 mm, were
randomly assigned to an 8-mm-tip thermocouple catheter with a
power limit of 70 W and a target temperature of 60°C (Saint-Jude EP
Technologies Livewire 8-mm-large curve-XLS, Daig Corp) or to
ablation with an irrigated 5-mm-tip thermocouple catheter (CordisBiosense-Webster Thermocool-F-curve, Diamond Bar) with a
temperature-controlled RFA delivery at a power limit of 40 W and a
target temperature of 50°C applied for 60 seconds at each point.
Study Population
Patient characteristics are summarized in Table 1. Seventysix patients (41%) had structural heart disease. Structural
heart disease included 26 cases of ischemic cardiomyopathy
(previous bypass surgery in 6), 25 of dilated cardiomyopathy,
2 of hypertrophic cardiomyopathy, 4 of right ventricular
dysfunction caused by pulmonary hypertension, 2 of interatrial communication (1 with previous surgery), and 17 of
valvular heart diseases: mitral regurgitation in 10 patients,
aortic regurgitation in 3 patients, mild mitral stenosis with
regurgitation in 2 patients, and aortic prostheses in 2 patients.
Before ablation, 148 patients were on antiarrhythmic drugs
(Vaughan Williams classification): class Ic (n⫽36), class III
(n⫽100), class II (n⫽8), and class IV (n⫽7). At the beginning of the procedure, 133 patients were in AFL, 43 in sinus
rhythm, and 9 in atrial fibrillation. Patients in sinus rhythm
underwent burst pacing (coronary sinus or low right lateral
Da Costa et al
TABLE 1.
Population Characteristics
Study Population
Values
Age, y
67⫾11
Sex (% women)
32/185 (17.3%)
Structural heart disease
76/185 (41%)
History of previous atrial fibrillation
148/185 (80%)
Oral anticoagulant agent, previous AFL RF
112/185 (60.5%)
Left atrial systolic diameter, mm
42.6⫾7
Left ventricular ejection fraction, %
58⫾12
Systolic pulmonary pressure, mm Hg
38⫾13
Inferior vena cava isthmus length, mm
32⫾6.6
No. of applications for validated RFA (⬎30 min)*
12.8⫾13
X-ray exposure, min
14.3⫾13
Procedure duration, min
Follow-Up
72⫾26
Antiarrhythmic drug after discharge
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After a mean follow-up of 9.5⫾5 months, AFL recurred in 4
of 185 patients (2.2%), and a second successful ablation
procedure was performed, obtaining a bidirectional isthmus
conduction block (Table 4). One patient required a third RFA.
75/185 (40.5%)
Anticoagulant agent after discharge
Aspirin
92/185 (49.7%)
Oral anticoagulant agent
93/185 (50.3%)
1033
eurysms requiring surgical treatment). In patients with long
CTI (n⫽62), 32 patients were randomly assigned to the 8-mm
group and 30 patients to the cooled-tip RFA group.
Overall, the duration of applications (9.9⫾11 versus
18.6⫾15 minutes; P⬍0.0001) and x-ray exposure (11.7⫾11
versus 19.5⫾16 minutes; P⫽0.0001) differed significantly
between patients with short and long CTI. Patients with short,
straight CTI had significantly (P⬍0.05*) lower RFA applications and x-ray exposure compared with all other CTI
morphologies: short, straight* (5.7⫾4.6 RF applications and
7.8⫾6 minutes x-ray; n⫽83); short, concave (17⫾14 and
17.5⫾13; n⫽24); short, pouch-like recess (20⫾18 and 23⫾16;
n⫽16); long, straight (17⫾15 and 19⫾20; n⫽25); longconcave (19⫾16 and 19.5⫾14; n⫽20); and long, pouch-like
recess (21⫾14 and 20⫾13; n⫽17).
86/185 (46.5%)
Antiarrhythmic agent, previous AFL RF
Atrial Flutter and Ablation
*Successful RF ablation of atrial flutter is validated only when the bidirectional block is still present after a 30-minute waiting period.
Discussion
Major Findings
This randomized study evidenced that cooled-tip and largetip catheters are equally efficient and safe for ablation of AFL
in patients presenting with long CTIs. Both techniques yield
the same results in terms of procedure parameters and
primary success rates as well as similar low arrhythmia
recurrence rates. Both ablation techniques appear to be
equally safe.
Both CTI length and isthmus characteristics such as concavity and the presence of pouch-like recesses are factors that
significantly increase procedure duration and x-ray exposure
and required RF applications.
atrium) at cycle lengths as short as 180 ms to obtain a flutter.
The sinus rhythm was restored by electric cardioversion
(internal or external) for patients in atrial fibrillation (n⫽9),
and the decision to ablate was based on a documented ECG
of typical AFL.
Angiographic and AFL Ablation Results
Angiographic analyses are summarized in Tables 2 and 3.
Anatomic morphology was assessed: 108 patients had a
straight CTI, 44 patients had a concave CTI with a mean
depth of 5⫾2.9 mm (range, 2.6 to 11.7 mm), and 33 patients
presented a pouch-like recess with a mean depth of 6.9⫾2.6
(range, 2.1 to 12.4 mm).
RFA results are summarized in Table 4. Bidirectional
block was obtained in 99% of patients, with a mean RF
application time of 12.8⫾13 minutes and mean fluoroscopic
time of 14⫾13 minutes. There were 2 local significant
procedure-related complications (2 false arterial femoral anTABLE 2.
Comparison Between 8-mm-Tip and
Cooled-Tip Catheters
Previous studies of AFL therapy with irrigated and large-tip
catheters versus 4-mm tips reported shorter ablation duration,
less x-ray exposure, and fewer RF applications.12–15,19 In
addition, experimental studies20,21 and nonrandomized studies
Angiographic Results and Ablation Measurements
No. of
Patients
RF Applications,
min
X-Ray
Exposure, min
185
13⫾13
14⫾13
Short (ⱕ35 mm)
123
10⫾11
12⫾11
Short, straight
83
6⫾5
8⫾6
Short, concave
24
17⫾14
17⫾13
Short, pouch-like recess
16
20⫾18
23⫾16
Long (⬎35 mm)
62
19⫾15
20⫾16
Long, straight
25
17⫾15
19⫾20
Long, concave
20
19⫾16
20⫾14
Long, pouch-like recess
17
21⫾14
20⫾13
CTI Dimension
Population, 32⫾6.6 mm, mean⫾SD
Type of CTI
1034
Circulation
TABLE 3.
August 31, 2004
Group Comparison
Age, y⫾SD
Sex (% women)
CTI ⬎35 mm,
Irrigated-Tip,
Randomized (n⫽30)
CTI ⬎35 mm,
8-mm Tip,
Randomized (n⫽32)
CTI ⱕ35 mm,
8-mm Tip,
Nonrandomized (n⫽123)
71⫾11 (P⬍0.05)
67⫾9
66⫾11
5/30 (16.6%)
2/32 (6.25%)
25/123 (20.3%)
Left ventricular ejection fraction
57⫾15
56⫾13
59⫾11
Symptom duration, mo⫾SD
7.3⫾14
9⫾14
10⫾24
16/30 (53.3%)
12/32 (37.5%)
58/123 (47.2%)
8/30 (60%) (P⬍0.05)
13/32 (41%)
44/123 (36%)
47⫾8 (P⬍0.0001)
45⫾8 (P⬍0.05)
41⫾6
39.9⫾4 (P⬍0.0001)
39.1⫾4 (P⬍0.0001)
28⫾4
40⫾15
40⫾10
37⫾13
16/30 (53.3%)
11/32 (35%)
48/123 (39%)
Preablation history of atrial fibrillation
Structural heart disease, %
Left atrial size, mm
Cava tricuspid isthmus, mm
Systolic pulmonary pressure, mm Hg
Antiarrhythmic drugs discharge
Regarding P values, no significant difference was found between the irrigated-tip and 8-mm-tip groups compared
with the short-CTI (⬍35 mm) group.
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demonstrated that cooled-tip catheters seemed more effective
and as safe as 8-mm-tip catheters.12–15 Thus, ablation of
typical AFL with an irrigated-tip catheter was recently
recommended as first-line therapy.22 Only 2 randomized
studies demonstrated that both catheter techniques were
equivalent, although several limitations were underlined.14,23
We hypothesized here that RFA lesions were expected to
be deeper with a cooled-tip RFA catheter, and the large
surface area of the 8-mm-tip catheter may provide a cooling
effect that simulates what happens with a cooled-tip catheter.
These 2 catheter techniques were thus applied to presumedly10,11 difficult ablations, patients with long CTI (⬎35 mm).
Results demonstrated equivalence in this subset of patients.
An open-loop showerhead catheter was chosen here, whereas
in 2 published studies, the catheter used was a closed-loop
cooled-tip catheter: both studies arrived at similar results
compared with 8-mm-tip catheters.14,23
TABLE 4.
Impact of Right Atrial Length and Anatomy for
AFL RFA
Previous anatomic and angiographic reports studying human
hearts have pointed to the anatomic variability of the isthmus,
reporting an average width of 27⫾3.3 to 37⫾8 mm and different
morphologies.9,10,24 In a landmark study, the authors revealed a
highly variable isthmus anatomy and its impact to adjust the
ablation tactic.10 The presence of a eustachian valve or concave
isthmus was associated with statistically more RF applications,
and the same trend was seen for patients with deep pouches.10
Our angiographic study, the largest on this subject, demonstrates that CTI morphology and CTI length affect RF
procedures. Fewer RF applications and less x-ray exposure
could be correlated with patients with short, straight CTIs.
Study Limitations
Right atrial angiography provides a guide to CTI anatomy but
no detailed information regarding the thickness of the isth-
Procedural Parameters of Ablation (Intention-to-Treat Analysis) and Follow-Up
Coronary catheterization fluoroscopic time, min
CTI ⬎35 mm, Irrigated Tip,
Randomized (n⫽30)
CTI ⬎35 mm, 8-mm Tip,
Randomized (n⫽32)
CTI ⱕ35 mm, 8-mm Tip,
Nonrandomized (n⫽123)
2.25⫾2.3
1.7⫾1.9
1.7⫾1.9
No. of applications to interrupt AFL, min
10⫾10 (P⬍0.0001)
7⫾6 (P⬍0.05)
No. of applications for bidirectional isthmus
block, min
16⫾10 (P⬍0.0001)
15⫾15 (P⬍0.001)
9⫾10
No. of applications for validated RFA (⬎30
min),* min
19⫾13 (P⬍0.0001)
18⫾17 (P⬍0.001)
10⫾11
Crossover
7/30 (23%) (P⬍0.05)
6/32 (19%) (P⬍0.05)
10/123 (8%)
Conduction recurrence within 30 min
11/30 (37%) (P⬍0.05)
6/32 (20%)
20/123 (16%)
1/30
0/32
1/123
X-ray exposure, min
18⫾13 (P⬍0.001)
21⫾18 (P⬍0.0001)
12⫾11
Procedure duration, min
90⫾29 (P⬍0.0001)
81⫾30 (P⬍0.0001)
65⫾20
11.1⫾5.6
11.2⫾5.4
9⫾5
0
0
4
3 (10%)
7 (22%)
14 (11.4%)
Bidirectional block failure
Mean follow-up, mo
Atrial flutter recurrence: 4/185 (2%)
Atrial fibrillation: 24/185 (13%)
3.6⫾5
Regarding P values, no significant difference was found between the irrigated-tip and 8-mm-tip groups compared with the short-CTI (⬍35 mm)
group.
Da Costa et al
mus. Phased-array intracardiac echocardiography, a more
recent technique, could better define the cavotricuspid isthmus anatomy and thickness.25 The randomization between
8-mm and irrigated catheters could have been applied to the
entire patient population.
11.
12.
Conclusions
Irrigated and 8-mm-tip catheters are equally efficient in the
ablation of long CTIs. Angiographic correlation of isthmusdependent AFL with ablation reveals a significant correlation
between number of RF applications and CTI morphology.
Catheter assessments and comparisons should not be performed without precisely qualifying the target tissue
morphology.
13.
14.
15.
Disclosure
Dr Messier is an employee of the Medtronic Bakken Research Center
BV, 5 Endepolsdomein, 6229 GW Maastricht, the Netherlands.
16.
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Effect of Isthmus Anatomy and Ablation Catheter on Radiofrequency Catheter Ablation
of the Cavotricuspid Isthmus
Antoine Da Costa, Emmanuel Faure, Jérôme Thévenin, Marc Messier, Samuel Bernard, Kihel
Abdel, Christophe Robin, Cécile Romeyer and Karl Isaaz
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Circulation. 2004;110:1030-1035; originally published online August 23, 2004;
doi: 10.1161/01.CIR.0000139845.40818.75
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