tion (AF) were referred for ablation. All patients had documented AF episodes with an AF duration of 9.3+7.5 years
(range 1.5–25). The mean total procedure time was 139.30+37.72 (median 135, range 115–172). The mean fluoro-
scopy time required for PVAC ablation was 17+12 min (median 16, range 12–33) and the total fluoroscopy time
was 32.1+11.3 min (median 29, range 25–39). The mean multi-electrode RF ablation time required to achieve com-
plete PV isolation was 31+6.7 min (range 16–51). In eight patients with persistent AF, additional ablations were
performed to defragment septal and posterior part of the left atrium. In five patients additional RF ablations using
conventional catheters were necessary. After multi-electrode duty-cycled RF ablation, 62 of 102 (60.8%) patients
were in sustained sinus rhythm without anti-arrhythmic drugs. The mean follow-up duration was 12.2+3.9
months (range 6–15).
This novel multi-electrode ablation technique can be used for PV isolation and left atrium ablation with a relatively
low medium-term success rate after the first ablation of ?61%. Larger studies with longer follow-up are required to
evaluate the efficacy and whether multi-electrode RF ablation is associated with a different complication rate com-
pared with standard PV isolation.
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Atrial fibrillation † Multi-electrode ablation † Pulmonary vein isolation
Ablation for Atrial Fibrillation
Efficacy of multi-electrode duty-cycled
radiofrequency ablation for pulmonary vein
disconnection in patients with paroxysmal
and persistent atrial fibrillation
Rypko P. Beukema, Willem P. Beukema, Jaap Jan J. Smit, Anand R. Ramdat Misier,
Peter Paul H.M. Delnoij, Hein Wellens, and Arif Elvan*
Department of Cardiology, Isala Klinieken, Groot Wezenland 20, 8011 JW Zwolle, The Netherlands
Received 20 August 2009; accepted after revision 19 January 2010; online publish-ahead-of-print 25 February 2010
A novel multi-electrode pulmonary vein ablation catheter (PVAC) combining circular mapping and duty-cycled multi-
electrode radiofrequency (RF) energy delivery has been developed to map and isolate the pulmonary veins (PVs). The
aim of this study was to assess the efficacy of multi-electrode RF ablation using the PVAC device.
A total of 102 consecutive patients, age 57.9+9.6 years, with paroxysmal or persistent drug refractory atrial fibrilla-
Catheter ablation of atrial fibrillation (AF) is an acceptable option
in patients whose quality of life is severely disturbed by AF and the
arrhythmia has not responded to drug therapy or cardioversion.1
Catheter ablation of AF requires expertise and remains a time-
consuming procedure.2–7Newer catheter designs have been
developed to reduce procedure time.8–13Radiofrequency (RF)
ablation has become a successful therapeutic option for patients
with symptomatic AF. Isolation of triggers within the pulmonary
veins (PVs) is the main treatment strategy in these patients.2Con-
ventional techniques use a ring-shaped mapping catheter and a
second ablation catheter that applies RF energy in a unipolar
fashion. Complete isolation of all electrical potentials at the PV
ostium is a technically challenging procedure requiring a long learn-
ing curve and extensive fluoroscopy. In addition, serious compli-
atrio-oesophageal fistulas by inadvertent high-power delivery.1–7
* Corresponding author. Tel: þ31 31 38 4242374; fax: þ31 31 38 4243222, Email: email@example.com
Published on behalf of the European Society of Cardiology. All rights reserved. & The Author 2010. For permissions please email: firstname.lastname@example.org.
Europace (2010) 12, 502–507
by guest on June 8, 2015
New developments in catheter ablation of AF have attempted to
address these challenges in a variety of methods. The pulmonary
vein ablation catheter (PVAC) (Medtronic, Ablation Frontiers,
Carlsbad, CA, USA) is a novel circular multi-electrode catheter
that has been used to isolate PVs with duty-cycled radiofrequency
energy. This multi-electrode over the wire device capable of circu-
lar mapping and RF energy delivery is intended to simplify the PV
isolation procedure while reducing the risk of complications.
Limited data are available on the safety and efficacy of this
approach.8The objective of this study was to evaluate the efficacy
of multi-electrode duty-cycled RF ablation with the use of PVAC.
A total of 102 patients with paroxysmal or persistent AF, who were
scheduled to undergo elective PV disconnection and left atrial ablation,
were included in a prospective registry. None of the patients had an
ablation procedure before. All patients consented to their data being
registered and used for publication as did the Board of Hospital
Administrators. Patients were admitted 24 h prior to the ablation pro-
cedure. During hospitalization, cardiac rhythm in all patients was con-
tinuously monitored. Transthoracic echocardiography was performed
routinely prior to ablation to determine right and left ventricular func-
tion, valvular abnormalities, and left and right atrial dimensions. Trans-
oesophageal echocardiography was performed to assess inter-atrial
septum and to rule out intra-cardiac thrombus. Multi-slice CT angio-
graphy was performed in all patients to asses the anatomy of the
PVs, left atrium, and adjacent structures. Routine blood tests were per-
formed, including electrolytes and cardiac enzymes.
The ablation procedures were performed under conscious sedation or
general anaesthesia. Two return electrode patches were placed between
the scapulae. Two fixed-curve 8.5F SL-1 sheaths (St Jude Medical), and
in selected cases a steerable sheath (Channel, Bard, Lowell, MA, USA),
were introduced into the right femoral vein. A 6F deflectable quadripo-
lar electrode catheter (Bard) was positioned into the coronary sinus.
Transseptal puncture was performed with a modified Brockenbrough
needle. An initial bolus of 10000 units of heparin was given and
2500–5000 unit IV additional boluses to maintain an activated clotting
time (ACT) between 300 and 350 s were given. ACT was determined
every 30 min. Pulmonary vein angiography was performed for all PVs
in anteroposterior, 308 left anterior oblique and 308 right anterior
oblique positions to provide a geometric reference for catheter naviga-
tion. The PVAC (Medtronic, Ablation Frontiers) is a mapping and
ablation catheter with a 25 mm diameter circular electrode array. This
catheter has a bidirectional steering mechanism and an over-the-wire
design. The details of this device have been described previously.8
Experience with the PVAC in our centre was gained prior to this
study in a pilot study of 15 patients.
The PVAC was introduced into the left atrium via the SL-1 sheath.
Using a 0.032 in. guidewire placed in the vein, the catheter was posi-
tioned at the antrum of each PV to record local electrical activity at
the veno-atrial junction prior to RF energy application. The PV ostia
were visualized by selective contrast injection. Figure 1 is a representa-
tive example showing the fluoroscopic image of the position of the
PVAC at the ostium of the left superior PV and the recorded electro-
grams at this position are shown in Figure 2. The positions of the PVAC
catheter were documented using fluoroscopy. RF energy was applied
using the RF generator with a target temperature of 608C, 4:1 or 2:1
ratio between bipolar and unipolar energy, and 60 s duration. Multiple
applications of RF were delivered using the available energy settings
until isolation of the antrum of each vein was achieved. After extensive
ablations were performed at all veno-atrial junctions, the PVAC was
used to map all PV ostia. With the aid of the steerable channel
sheath, the PVAC could be deployed in all right inferior pulmonary
veins (RIPVs). If the PVs appeared to be incompletely isolated,
additional RF applications were delivered using the PVAC until the
PVs were completely disconnected based on PVAC signals. Thirty
minutes post-ablation all PVs were mapped again with the PVAC and
if necessary additional ablations were performed. In the case of
failure to isolate the PVs with the PVAC, a conventional irrigated tip
ablation catheter was used to isolate the PVs.
Radiofrequency generator settings
The GENiusTMgenerator (Medtronic, Ablation Frontiers) is a multi-
channel RF generator capable of simultaneously delivering duty-cycled
energy to up to 12 operator-selected electrodes. The generator has
five preset energy settings: bipolar, unipolar, and three ratios of
bipolar-to-unipolar energy: 4:1, 2:1, and 1:1. The energy was delivered
in a temperature-controlled, power-limited manner with a maximum
of 10 W per electrode. The generator displays in real-time the temp-
erature and power for each electrode, as well as the number of
seconds each electrode was within 58C of target temperature during
Post-ablation management and follow-up
Post-ablation, patients were hospitalized for at least 24 h and moni-
tored telemetrically. AF recurrence was defined as an atrial arrhythmia
Figure 1 Angiography (AP view) of the left atrium and the left
sided pulmonary veins. In this representative example, the PVAC
catheter is positioned in the LSPV. AP, anteroposterior; LA, left
atrium; CS, coronary sinus; LIPV, left inferior pulmonary vein;
LSPV, left superior pulmonary vein; PVAC, pulmonary vein
ablation catheter. See text for details.
Multi-electrode ablation in patients with atrial fibrillation
by guest on June 8, 2015
of .30 s. Low-molecular-weight heparin was given for 2–7 days and
acenocoumarol for at least 3 months. Anti-arrhythmic drugs (Class I
or III) were continued during the first 3 months and gradually
tapered. About 24–48 h Holter monitoring was performed at 3, 6,
and 12 months intervals. Furthermore, 1-week AF alarm monitoring
was performed 6+1.5 (range 5–8) months after ablation. The AF
alarm is a battery-powered electronic arrhythmia detection device
with ECG recording capabilities. The device automatically detects
arrhythmias and stores a digitalized ECG of arrhythmias. Furthermore,
ECG storage can also be manually triggered to investigate if symptomatic
episodes are actually related to an arrhythmia.14Oesophagoscopy was
not performed routinely post-procedure. Transthoracic echocardiogra-
phy was performed 1 day after the procedure in all patients. All patients
visited our outpatient clinic at 1, 3, 6, and 12 months intervals. A stan-
dard 12-lead ECG was recorded at each outpatient visit. Transthoracic
echocardiography and spiral CT or magnetic resonance imaging of the
PVs were performed 3 months after RF ablation to document atrial
size and PV ostial dimensions, respectively.
Categorical variables are expressed as frequencies and percentages.
Continuous data are presented as mean+SD. Comparison of con-
tinuous variables was performed with the Student’s t-test. Comparison
of proportions was performed with the x2analysis or Fisher’s exact
test. All P-values are two-sided and P-value ,0.05 was considered stat-
istically significant. A two-tailed P value of ,0.05 indicated statistical
significance. Statistical analysis was performed using SPSS (SPSS Inc,
Chicago, IL, USA).
Clinical characteristics of the patients
A total of 102 consecutive patients, age 57.9+9.6 years, with par-
oxysmal (n ¼ 90) or persistent (n ¼ 12) drug refractory AF were
referred for ablation. All patients had documented AF episodes
with an AF duration of 9.3+7.5 years (range 1.5–25). Clinical
characteristics of the patients are summarized in Table 1. Echocar-
diographic recordings demonstrated an average left atrial size of
41.2+6.5 mm in the parasternal long-axis view. Left ventricular
ejection fraction was 59+4.3 (range 45–61).
The mean total procedure time was 139.30+37.72 (median 135,
range 115–172), including transseptal puncture and pre- and post-
ablation mapping of the PVs. PV angiography was performed prior
to ablation. Thirty patients had a left common trunk (Table 2).
Deployment of the PVAC was successful in all the left-sided PVs
and all right superior PVs. Deployment of the PVAC was not suc-
cessful in 17 right inferior PVs. In these patients, a steerable
channel sheath (Bard) was used. In 12 (11.8%) patients with per-
sistent AF, the superior vena cava (SVC) was isolated using the
PVAC. In 3 of these 12 patients, AF was converted to sinus
rhythm during RF application around the SVC. The mean duty-
cycled RF ablation time required to achieve complete PV isolation
was 31+7 min (range 16–51).
Figure 2 Tracings are surface ECG leads I, III, and V1 and intra-cardiac signals recorded from the proximal pair of a quadripolar catheter
positioned in the coronary sinus and the pulmonary vein ablation catheter positioned in the left superior pulmonary vein. (A) The pre-ablation
signals during sinus rhythm; (B) the pre-ablation signals during coronary sinus pacing; and (C and D) the signals post-ablation during sinus rhythm
and coronary sinus pacing, respectively. See text for details.
R.P. Beukema et al.
by guest on June 8, 2015
The RF duration for complete PV isolation tended to be greater
for the common trunks in comparison with the other veins
(P-value left common trunk vs. others, P , 0.01). Table 2 summar-
izes the procedural data including PVAC ablation time per PV.
There was no statistically significant difference in the PVAC abla-
tion time between the right-sided and the left-sided PVs except
for the left common trunks. The mean fluoroscopy time required
for PVAC ablation was 17+12 min (median 16, range 12–33) and
the total fluoroscopy time was 32.1+11.3 min (median 29, range
Cardiac rhythm during follow-up
The mean follow-up duration was 12.2+3.9 months (range
6–15). In the total study population (n ¼ 102), 62 (60.8%) patients
were in sustained SR without anti-arrhythmic drugs. In the parox-
ysmal AF group (n ¼ 90), after the PVAC ablation procedure, 58
patients (64.4%) had sustained SR without anti-arrhythmic drugs.
In the paroxysmal AF group, 11 (12.2%) patients with recurrent
AF/AFl during follow-up underwent Lasso and Carto guided
re-ablation using conventional irrigated tip catheters. In all the
11 patients, gaps in the ablation lines were identified and additional
ablations were applied to create complete circumferential PV iso-
lation. Three patients had a gap at the ridge between the left
superior PV and the left atrial appendage. Three patients had a
gap at the antero-inferior part of the right inferior PV antrum.
Five patients had gaps at both right- and left-sided LA–PV junc-
tions. Three patients had a drug refractory and highly symptomatic
left atrial flutter after the PVAC procedure. Electro-anatomic
propagation mapping and entrainment mapping were performed.
These atrial flutters were due to incomplete ablation lines at the
junction of the left superior PV and the left atrial appendage in
two patients and an incomplete ablation at the anterior part of
the RIPV antrum in one patient. All patients underwent successful
flutter ablation. In the persistent AF group (n ¼ 12), six patients
(50%) had AF recurrences. Four of these six patients underwent
re-ablation with isolation of PVs, defragmentation of the left
atrium, and isolation of the SVC. For defragmentation, multi-array
septal catheter and multi-array ablation catheter were used.
Figure 3 shows the cardiac rhythm during the follow-up of the
total study population. Oral anti-coagulation was taken by all
There were no procedural complications in this study. Specifically,
there was no thrombus formation or charring detected on the
electrodes of the PVAC catheter. Additionally, there were no
phrenic nerve injuries and no oesophageal damage revealed
by oesophagoscopy. CT angiography of the PVs performed
3 months post-ablation did not reveal PV stenosis.
The main findings are that duty-cycled multi-electrode ablation
with the PVAC can be used for PV isolation with an acute
success rate for PV isolation of 95% using the PVAC alone. In a
minority of the patients (5%), PV isolation could not be achieved
with the PVAC and additional ablations using conventional
catheters were necessary. Furthermore, after a mean follow-up
of 12 months, freedom from AF/AFl after multi-electrode duty-
cycled RF ablation was ?61% (i.e. percentage of patients in SR
without anti-arrhythmic drug therapy).
No. of patients
No. of cardioversions
No. of ineffective AADs
History of TIA/stroke
Ischaemic heart disease
Family history of AF
Left atrial size PSLAX (mm)
Duration of AF (years)
Type of AF
Table 1 Baseline patient characteristics
RSPV 10220.6+4.3 5.6+1.61
Overall 378 20.9+4.8 31+6.75
Table 2 Procedural data
PVAC RF time
Additional ablations with irrigated tip
catheter (n, pts)
Final confirmation of PV
*P , 0.01 LCPV vs. other PVs;#P , 0.01 LCPV vs. other PVs.
Multi-electrode ablation in patients with atrial fibrillation
by guest on June 8, 2015
Boersma et al.8reported that duty-cycled bipolar/unipolar RF abla-
tion is effective in isolating PVs using relatively low power
(,10 W). The success rate, defined as freedom from AF
without anti-arrhythmic drugs, was 83% with a follow-up duration
of 6 months.8Unfortunately, there is no information regarding the
distribution among both types of AF (persistent vs. paroxysmal) in
this latter study. Our data indicate a lower success rate. The poss-
ible explanations in the different success rates may be the longer
follow-up duration in our study and/or the intensity of rhythm
monitoring post-ablation. Scharf et al.15investigated the efficacy
and safety of duty-cycled RF ablation with multi-electrode ablation
in 50 patients with long-standing persistent AF. The 6-month
success rate was 80% and the 20-month success rate 66%.
However, success was defined as a ?80% reduction in AF
burden on the 7-day ECG recording at 6 months, with or
without anti-arrhythmic drug treatment. In fact, only 54% of
patients were free of AF without anti-arrhythmic drugs after
Symptomatic vs. asymptomatic atrial fibrillation
Vasamreddy et al.16demonstrated that PV isolation resulted in 70%
of patients remaining free of symptomatic AF recurrences over a
6-month time period, while only 50% remained free of episodes
Figure 3 This diagram shows the radiofrequency ablation results. (A) Circle diagram showing pulmonary vein ablation catheter and
re-ablation results for patients with paroxismal and persistent AF. (B) Results for separate categories (persistent-, paroxismal AF, with- and
without anti-arrhythmic drugs). RFCA, radiofrequency ablation; AF, atrial fibrillation; SR, sinus rhythm; AAD, anti-arrhythmic drugs.
R.P. Beukema et al.
by guest on June 8, 2015
when asymptomatic AF recurrences were included in the Download full-text
outcome. Purerfellner et al.17demonstrated that many patients
had many more asymptomatic AF episodes than formerly known
or documented post-ablation. Long-term follow-up of the patients
seems to be essential as success rates of the initial ablation pro-
cedure might vary over time. Freedom from AF after conventional
ablation varies between 80 and 90%.3–5
PVAC compared with other pulmonary vein
Multi-electrode duty-cycled RF ablation is a relatively novel abla-
tion technique and was designed to make PV isolation procedures
less complex and less time-consuming, since a single catheter can
be used to produce contiguous lesions with each RF application.
Our data indicate that freedom from AF after PVAC ablation is
relatively low compared with published results of conventional
ablation techniques.3–5Conventional techniques use a circular
mapping catheter and a second ablation catheter to deliver RF
energy in a unipolar fashion. Complete isolation of all electrical
potentials at the PV ostium is a technically more challenging pro-
cedure requiring a longer learning curve and extensive fluoro-
scopy. New developments in catheter ablation of AF have
attempted to address these challenges in a variety of methods.
Arentz et al.18found that large circumferential periostial large
area ablation around ipsilateral PVs with verification of conduction
block is a more effective treatment of AF than isolation of each
individual PV. Although the procedure and ablation times were sig-
nificantly longer for isolation of large areas, the fluoroscopy time
with a three-dimensional mapping system was significantly
shorter. Recent technical advances in robotic and magnetic steer-
ing have facilitated catheter manipulation and demonstrated
reduced radiation dosage for the physician, but are likely to
increase procedural complexity, cost, and time. Variations on cath-
eter design have also been proposed, with coiled electrodes
implemented on helical and linear catheters demonstrating
Alternative catheter shapes combined with novel energy sources
have been proposed and are being evaluated in the clinical
setting, including balloon catheters that deliver laser, cryoablation,
and ultrasound energy.9–13However, these approaches are yet to
demonstrate the ability to consistently isolate all veins without sup-
plemental ablation catheters. Procedure or fluoroscopy times are
not reduced, and reports have shown collateral damage compli-
cations such as phrenic nerve damage.
Limitations and clinical implications
This study suggests that PVAC can be used for PV isolation.
However, percentage of patients free from AF after ablation is rela-
tively low (?58%). The follow-up duration is relatively short and
longer follow-up is necessary to assess the long-term efficacy of
this ablation technique. Although the PVAC has the potential
advantage of being both a therapeutic and diagnostic tool, the
current version of the PVAC is not ideal for larger veins. Therefore,
CT or MR imaging of the PVs prior to ablation is needed to select
patients. In the majority of the patients, this single catheter can be
used to isolate the PVs and document isolation without switching
to another mapping catheter. The ablations with the PVAC can be
performed using a single transseptal puncture. The complication
rate seems to be low, there were no adverse events in this
study. However, only limited reports of experience with PVAC
ablation have been published. Larger studies are required to evalu-
ate whether the PVAC is associated with a different complication
rate compared with standard PV isolation.
Conflict of interest: none declared.
1. HRS/EHRA/ECAS. Expert consensus statement on catheter and surgical ablation
of atrial fibrillation; recommendations for personnel, policy, procedures and
follow-up. Hearth Rhythm 2007;4:1–46.
2. Haı ¨ssaguerre M, Jaı ¨s P, Shah DC, Takahashi A, Hocini M, Quiniou G et al. Spon-
taneous initiation of atrial fibrillation by ectopic beats originating in the pulmonary
veins. N Engl J Med 1998;339:659–66.
3. Pappone C, Augello G, Sala S, Gugliotta F, Vicedomini G, Gulletta S et al. A ran-
domized trial of circumferential pulmonary vein ablation versus antiarrhythmic
drug therapy in paroxysmal atrial fibrillation. J Am Coll Cardiol 2006;48:2340–7.
4. Ouyang F, Ba ¨nsch D, Ernst S, Schaumann A, Hachiya H, Chen M et al. Complete
isolation of left atrium surrounding the pulmonary veins: new insights from the
double-Lasso technique in paroxysmal atrial fibrillation. Circulation 2004;110:
5. Jaı ¨s P, Cauchemez B, Macle L, Daoud E, Khairy P, Subbiah R et al. Catheter abla-
tion versus antiarrhythmic drugs for atrial fibrillation: the A4 study. Circulation
6. Stevenson WG, Epstein LM. Endpoints for ablation of atrial fibrillation. Heart
7. Kottkamp H, Hindricks G, Autschbach R, Krauss B, Strasser B, Schirdewahn P
et al. Specific linear left atrial lesions in atrial fibrillation. Intraoperative radiofre-
quency ablation using minimally invasive surgical techniques. J Am Coll Cardiol
8. Boersma LV, Wijffels MC, Oral H, Wever EF, Morady F. Pulmonary vein isolation
by duty-cycled bipolar and unipolar radiofrequency energy with a multielectrode
ablation catheter. Heart Rhythm 2008;5:1635–42.
9. Meissner A, Plehn G, Van Bracht M, Schrage MO, Christ M, Maagh P et al. First
experiences for pulmonary vein isolation with the high-density mesh ablator
(HDMA): a novel mesh electrode catheter for both mapping and radiofrequency
delivery in a single unit. J Cardiovasc Electrophysiol 2009;20:359–66, Epub 27
10. Pratola C, Notarstefano P, Artale P, Toselli T, Baldo E, Marcantoni L et al. Radio-
frequency ablation of paroxysmal atrial fibrillation by mesh catheter. J Interv Card
Electrophysiol 2009;25:135–40, Epub 16 January 2009.
11. Mansour M, Forleo GB, Pappalardo A, Heist EK, Avella A, Laurenzi F et al. Initial
experience with the mesh catheter for pulmonary vein isolation in patients with
paroxysmal atrial fibrillation. Heart Rhythm 2008;5:1510–6.
12. Schmidt B, Antz M, Ernst S, Ouyang F, Falk P, Chun JK et al. Pulmonary vein iso-
lation by high-intensity focused ultrasound: first-in-man study with a steerable
balloon catheter. Heart Rhythm 2007;4:575–84.
13. Chun KR, Schmidt B, Metzner A, Tilz R, Zerm T, Ko ¨ster I et al. The ‘single big
cryoballoon’ technique for acute pulmonary vein isolation in patients with parox-
ysmal atrial fibrillation: a prospective observational single centre study. Eur Heart J
14. Beukema R, Beukema WP, Sie HT, Ramdat Misier AR, Delnoy PP, Elvan A. Moni-
toring of atrial fibrillation burden after surgical ablation: relevancy of end-point
criteria after radiofrequency ablation treatment of patients with lone atrial fibrilla-
tion. Interact Cardiovasc Thorac Surg 2009;9:956–9.
15. Scharf C, Boersma L, Davies W, Kanagaratnam P, Peters N, Paul V et al. Ablation
of persistent atrial fibrillation using multielectrode catheters and duty-cycled
radiofrequency energy. J Am Coll Cardiol 2009;54:1450–6.
16. Vasamreddy CR, Dalal D, Dong J, Cheng A, Spragg D, Lamiy S et al. Symptomatic
and asymptomatic atrial fibrillation in patients undergoing radiofrequency catheter
ablation. J Cardiovasc Electrophysiol 2006;17:134–9.
17. Purerfellner H, Aichinger J, Martinek M, Nesser HJ, Ziegler P, Koehler J et al.
Quantification of atrial tachyarrhythmia burden with an implantable pacemaker
before and after pulmonary vein isolation. PACE 2004;27:1277–83.
18. Arentz T, Weber R, Burkle G, Herrera C, Blum T, Stockinger J et al. Small or large
isolation areas around the pulmonary veins for he treatment of atrial fibrillation?
Results from a prospective randomized study. Circulation 2007;115:3057–63.
Multi-electrode ablation in patients with atrial fibrillation
by guest on June 8, 2015