Catheter Ablation of Atrial Fibrillation Using Zero-Fluoroscopy Technique: A Randomized Trial ALAN BULAVA, M.D., PH.D.,*,† JIRI HANIS, M.D.,* and MARTIN EISENBERGER, M.D., PH.D.*,† From the *Department of Cardiology, Budweis Hospital, Budweis, Czech Republic; and †Faculty of Health and Social Studies, University of South Bohemia, Budweis, Czech Republic

Background: Recent advances in 3D mapping systems, such as simultaneous visualization of multiple catheters and contact force measurement, have allowed a significant reduction in fluoroscopic times during radiofrequency (RF) ablation (RFA) procedures. The objective was to investigate whether RFA of paroxysmal atrial fibrillation (PAF) using the CARTO 3 system (Biosense Webster, Diamond Bar, CA, USA) and intracardiac echocardiography (ICE) can be performed safely without fluoroscopy. Methods and Results: Eighty patients with PAF were randomized in a 1:1 ratio to undergo either fluoroscopically guided pulmonary vein isolation (PVI) (X+) or PVI without fluoroscopy (X−). In the X− fluoroscopy group, catheter placement, transseptal puncture, left atrial geometry reconstruction, and PVI were accomplished solely using ICE imaging and CARTO mapping. The total procedure duration and RF application time in both the X− and X+ groups were comparable (92.5 ± 22.9 minutes vs 99.9 ± 15.9 minutes, P = 0.11 and 1785 ± 548 seconds vs 1755 ± 450 seconds, P = 0.79, respectively). Zero fluoroscopic time was achieved in all patients in the X− group with the exception of one patient, where 8 seconds of fluoroscopy was needed to assess proper position of the guide-wire in the femoral vein. No serious procedure-related complications were recorded and no differences in arrhythmia-free survival at 12 months were found between the groups. Conclusion: RFA using ICE imaging and the CARTO 3 mapping system with contact force measurement is capable of eliminating fluoroscopy in patients undergoing PVI. Exclusion of fluoroscopic imaging does not seem to compromise patient safety and does not affect overall procedure duration, RF application time, or mid-term efficacy. (PACE 2015; 38:797–806) atrial fibrillation, radiation, zero fluoroscopy, pulmonary vein isolation, contact force, catheter ablation

Introduction Radiofrequency (RF) ablation (RFA) of atrial fibrillation (AF) requires experience with transseptal (TS) punctures, careful manipulation of catheters, and mapping of the left atrium (LA). Conventionally, these steps are fluoroscopyguided, which exposes both patients and medical

This study was partially funded by the Faculty of Health and Social Studies, University of South Bohemia in Ceske Budejovice (BOV 2012_001). Conflict of Interest: None declared. The study was registered at www.ablace.cz under No cz100220141204. Address for reprints: Alan Bulava, M.D., Ph.D., Department of Cardiology, Budweis Hospital, Bozeny Nemcove 54, 370 01 Budweis, Czech Republic. Fax: 420-387874325; e-mail: [email protected] Received December 5, 2014; revised March 2, 2015; accepted March 13, 2014. doi: 10.1111/pace.12634

staff to significant and potentially dangerous ionizing radiation.1–5 Prolonged radiation exposure is known to increase the incidence of dermatitis, cataracts, malignancies, and congenital defects. For instance, the lifetime age- and sexaveraged risk for a fatal malignancy resulting from RFA requiring 60 minutes of fluoroscopy has been reported to range from 0.03% to 0.23%.6,7 Electrophysiology (EP) staff is at a particularly high risk of radiation-related complications due to the cumulative effect of ionizing radiation. Recent advances in RFA technologies and techniques have led to significant reductions in radiation exposure.8,9 A policy to minimize X-ray exposure during interventional procedures (known as ALARA, i.e., “as low as reasonably achievable”) has recently been adopted by occupational health groups.10,11 There is evidence that the catheter ablation of paroxysmal AF is safely feasible using a combination of intracardiac echocardiography (ICE) and Ensite NavX electroanatomical mapping system (St. Jude Medical, St. Paul, MN, USA).12

©2015 Wiley Periodicals, Inc. PACE, Vol. 38

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However, a prospective, randomized trial to compare standard and zero-fluoro approach has not been performed yet. Moreover, a few years ago the investigators did not have the advantage of recent technology developments in 3D mapping systems, such as contact force measurement. To overcome these limitations, we conducted a single center, prospective, randomized trial in patients undergoing a RFA for paroxysmal AF, in which we assessed the feasibility, safety, and efficacy of fluoroscopy elimination during RFA using ICE imaging and the CARTO 3 mapping system (Biosense Webster Inc., Diamond Bar, CA, USA) with contact force measurement. Methods Eighty consecutive patients with documented paroxysmal AF and no previous ablations were randomized between September and November 2013 into two groups. A simple envelope method was used for 1:1 treatment assignment. Paroxysmal type of AF was defined based on the expert consensus13 and the arrhythmia was verified either on a 12-lead electrocardiogram (ECG) or on Holter recording. The only exclusion criterion was unwillingness to participate in the study. In one group with standard care (X+), navigation techniques for all guide wires, introducer sheaths, and catheters were the same as those described in the “Fluoroless Catheter Manipulation” section (see below), except for the fact that the advancement of catheters, wires, and sheaths (including TS) and manipulation in the vasculature and in the heart were monitored using X-ray imaging whenever felt by the operator as needed, but still in accordance with the ALARA principle. TS puncture itself was achieved in the similar fashion using a standard technique as described in the “Fluoroless TS Puncture” section (see below), but the manipulation with the sheath was continuously visualized using X-ray. Positioning of the TS sheath and the puncture itself was performed under ICE guidance. Left atrial 3D geometry reconstruction and pulmonary vein (PV) isolation in the X+ group was performed same way as described in the “Fluoroless Reconstruction of Left Atrial Geometry” section and the “Catheter Ablation” section, respectively, but whenever the operators felt any manipulation difficulties, they might use X-ray imaging on top of 3D CARTO catheter visualization for assistance. Catheters and all other disposables used in both groups were the same. In the X− group, fluoroscopy was not used at all and the medical staff did not wear lead aprons during the procedure. Detailed description of the X– procedures follows. Anticoagulation was discontinued 5 days prior to the procedure and the period was bridged by the low-molecular-weight heparin. All patients underwent transesophageal

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echocardiography (TEE) and cardiac computed tomography (CT) with contrast one day before the procedure. The X– procedures were performed by a single operator (AB), while X+ procedures were carried out by all three experienced operators (AB, ME, and JH). The study was approved by the Institutional Ethics Committee. All patients signed an informed written consent and data were collected according to institutional guidelines corresponding with guiding principles of the Declaration of Helsinki. A Web-based secured registry was used to collect the data prospectively. The primary endpoint of the study was twofold: feasibility and safety (i.e., absence of any procedure-related adverse events), and acute and mid-term efficacy, i.e., achievement of PV isolation and arrhythmia-free survival at 12 months. Fluoroless Catheter Manipulation The procedure was performed via both left and right femoral veins. A deca-polar coronary sinus (CS) catheter (Dynamic XT, Boston Scientific, Marlborough, MA, USA) was carefully advanced through the inferior vena cava (IVC), R using a long 23-cm 7F insertion sheath (Avanti +, Cordis Corporation, Bridgewater, NJ, USA), until electrical potentials appeared on the distal poles, which indicated placement close to the junction of the IVC and the right atrium (RA). Any difficulties in catheter advancement were overcome by pulling back, providing slight rotation with a small bend, followed by continued insertion of the catheter. Similarly, a 10F ICE probe (Acunav, Biosense Webster, Inc.) was carefully placed in the RA under ultrasound visualization of the venous lumen until a typical “parking” position image, showing the cavotricuspid isthmus (CTI) and transverse section of the aortic root. To prevent inadvertent engagement of the ICE probe in the contralateral iliac vein or any of the side branches, instead of continuing up the IVC, we also used a long sheath, which was introduced R over the long wire (23 cm, 11 F Avanti +, Cordis Corporation, Bridgewater, NJ, USA). After bending, the CS catheter was maneuvered across the CTI and visualized with ICE. Then, visualization of the CS ostium was attempted (Fig. 1) and the CS catheter was rotated using a “cross-torque-back-and-forth” movement so that the tip became visible, on the ICE, in the CS ostium. Simultaneously, an A to V ratio >1, seen on the local electrocardiogram, on the distal bipole, was verified on the recording system (BARD Electrophysiology, Lowell, MA, USA). If necessary, the curve was slightly released and the catheter was advanced distally. When this maneuver was not feasible, positioning the CS catheter was postponed until LA geometry was

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of the LA was reconstructed using a 3.5-mm R Smart TouchTM irrigated-tip ThermoCool catheter (Biosense Webster Inc.). The point-bypoint acquisition method was used starting on the posterior wall of the LA and tagging the ostia of the PVs and mitral annulus using ICE imaging. At least 120 points were acquired in each patient before the geometry of the LA was integrated with the preprocedural CT image. To ensure a safe and reliable reconstruction of the left atrial anatomy, only points with visible, tactile contacts were acquired (Fig. 3). Catheter Ablation

Figure 1. Visualization of the coronary sinus (CS) ostium (marked with the ellipse) on intracardiac echocardiography. CS catheter (white arrow) is introduced into the proximal portion of the coronary sinus. For the purpose of clarity, the shaft of the CS catheter was outlined with yellow dots. Eustachian ridge is also visible (red arrow).

ascertained using the CARTO 3 system (version 3.2.3 with added SW modules: Version 3 Base [MEM], VisiTag, CartoMerge, and SmartTouch, see below). Fluoroless TS Puncture After administration of intravenous heparin, a 0.035´´ guide-wire for the TS sheath was advanced from the right femoral vein until it was observed to enter the RA—superior vena cava (SVC) junction on the ICE (Fig. 2A). A steerable TS sheath (8F, Channel, Boston Scientific, Marlborough, MA, USA) was introduced over the wire and its position in the SVC was verified using a small puff of physiological solution (Fig. 2B). Following this step, the TS sheath was pulled back (Fig. 2C), while rotating in a counter-cockwise direction, until the tip of the sheath was visible against the interatrial septum in the plane of the left PVs (Fig. 2D). After appropriate tenting was observed, the TS needle was advanced with a rapid movement from the dilator, and penetration across the septum was visualized by a small puff of the physiological solution (Fig. 2E). The dilator together with the TS sheath itself was thereafter carefully advanced over the needle into the LA under continuous ICE guidance (Fig. 2F). These steps were repeated for the second TS puncture. Fluoroless Reconstruction of Left Atrial Geometry After obtaining LA access, a PV mapping R catheter (LASSO , Biosense Webster Inc.) was advanced to the left superior PV and the anatomy

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After the anatomy of LA had been reconstructed, we commenced RF applications using VisiTag software. A RF generator (Stockert, Biosense Webster) was set up to deliver RF energy up to 35 W with a maximum temperature limit of 43°C. All PVs were isolated using wide circumferential lesions. Isolation of the PVs was confirmed using LASSO mapping catheter demonstrating both entry and exit block. Furthermore, rapid atrial pacing, up to 300 beats/min, was used to test noninducibility after achievement of PV isolation. If sustained AF (i.e., lasting > 60 seconds) was induced, the circumferential lesions were complemented with linear lesions connecting the contralateral superior and inferior PVs, with the aim of isolating the posterior wall of the LA (“box” lesion), and a linear lesion extending from the left inferior PV toward the mitral annulus.14 All endocardial ablation points were acquired automatically using the CARTO 3 VisiTagTM module. Catheter position stability was set for a minimum time of 8 seconds with a maximum movement range of 2 mm and a minimum force of 5 grams over 60% of time (Fig. 4). PV isolation and completeness of the linear lines were evaluated and verified using standard criteria (i.e., entry and exit block for PVs and box-lesion, counter-clockwise radiation of the activation wavefront when pacing above the mitral isthmus line and vice versa when pacing beneath the line). CTI ablation was performed in patients with ECG documentation typical for right atrial flutter prior to the procedure or in patients in whom typical flutter was induced during incremental atrial pacing at the end of the procedure. During CTI ablation, ICE and CARTO 3 guidance were also used to navigate the ablation catheter. Follow-Up Patients had follow-up visits at 1 month, 3 months, 6 months, and 12 months after the index procedure and were asked to undergo another (control) TEE examination at 3 months to detect

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Figure 2. (A) Visualization of the guide-wire (white arrow) for the transseptal sheath in the SVC. The ICE probe was retroflexed and slightly bent to the right. (B) Small puffs of saline solution via the dilator of the TS sheath produced bubbles and confirmed the proper position of the sheath in the superior vena cava. (C) After confirmation of proper position of the TS sheath in the SVC, the sheath was pulled back with a counterclockwise rotation and the tip of the dilator was followed, using ICE, along the SVC until it was close to the IAS. (D) TS sheath was subsequently maneuvered in a posterior direction so that it was visible against the IAS in the plane of the left pulmonary veins. Orifice of the LSPV is visible). (E) Further advancement of the TS sheath against the IAS produced tenting. The septum was punctured with the TSN. The tip of needle was visualized as a hyperechogenic structure (white arrow) and its correct position was additionally ascertained using a small puff of physiological solution producing “bubbles” in the LA (yellow arrow). (F) The dilator and thereafter the TS sheath itself were carefully advanced over the TSN into LA under continuous ICE visualization. IAS = interatrial septum; ICE = intracardiac echocardiography; LA = left atrium; LSPV = left superior pulmonary vein; SVC = superior vena cava; TS = transseptal ; TSN = transseptal needle.

eventual PV stenosis (defined as pulsed-wave Doppler velocity ࣙ100 cm/s). A 7-day ECG Holter was performed ±20 days before each scheduled follow-up visit except for the first one. Success was

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defined as the absence of both symptomatic and asymptomatic AF and/or any other supraventricular arrhythmias lasting more than 30 seconds on any of the 7-day Holter monitors during the entire

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Figure 3. Left atrial geometry was reconstructed in detail. The points were acquired only when the contact force sensor indicated a tactile force of at least 5 grams but not exceeding 30 grams (red circle). The green vector at the tip of the SmartTouch catheter (red arrow) indicates stable contact with the posterior wall. The stable contact results in green color of the vector tip (see also Fig. 4).

Figure 4. An example of catheter ablation of the right superior pulmonary vein. The vector of contact force (red arrow) indicates a stable contact of 9 grams (white arrow). All ablation points on the left CARTO panel were taken automatically (so called VisiTag points) using predefined criteria, which in our case meant that the system depicted ablation point only when the ablation catheter stayed on place for at least 8 seconds with a maximum movement range (instability) of 2 mm and a minimum force of 5 grams over 60% of ablation time. Points are color coded (yellow arrow) according to the force-time integral (FTI). Majority of VisiTag ablation points in this particular case show FTI of at least 350 grams. FTI = force-time integral.

follow-up. Both patients and those physicians, who performed follow-up, were blinded to the treatment assignment.

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Statistical Analysis Continuous variables are expressed as mean ± standard deviation. Categorical variables are

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Table I. Clinical and Demographical Data

N Age (years) Males/females Structural heart disease BMI Hypertension Prior stroke No of failed AA drugs LA diameter (mm) LA volume (CARTO) (ml) LV ejection fraction (%)

X− Group

X+ Group

P

40 61.6 ± 9.9 27 (67.5%)/13 (32.5%) 4 (10%) 29.7 ± 8.4 15 (37.5%) 0 (0%) 0.64 ± 0.48 43.0 ± 5.7 112 ± 28 66 ± 6

40 60.2 ± 11.1 25 (50%)/25 (50%) 5 (12.5%) 28.3 ± 3.5 15 (37.5%) 0 (0%) 0.65 ± 0.48 42.2 ± 7.2 103 ± 28 65 ± 7

NS NS NS NS NS NS NS NS NS NS

AA = antiarrhythmic; BMI = body mass index; LA = left atrium; LV = left ventricle.

presented as absolute numbers and frequencies. Differences between continuous variables were assessed using the Student’s t-test or MannWhitney U test, depending on the normality of data. Comparisons between categorical data were assessed using the χ 2 test (Pearson’s or Fisher’s exact test, as appropriate). In all analysis, P < 0.05 was considered statistically significant. Results Eighty patients were randomized into two groups—40 patients in the standard AF ablation group using fluoroscopy (X+) and 40 patients in the zero-fluoroscopy group (X–). Clinical data for both patient groups are presented in Table I. Only four (10%) and five (12.5%) patients in the X− and X+ group, respectively, had structural heart disease. Zero fluoroscopy time was achieved in 39 (97.5%) of the 40 patients in the X− group. One patient required 8 seconds of fluoroscopy to confirm appropriate sheath placement in the left groin after the patient complained of pain, despite repeated injections of local anesthetics, during sheath introduction. In 18 (45%) of 40 patients in the X− group, it was possible to advance the CS catheter to the CS prior to the TS puncture with only ICE and electrical signal guidance (Fig. 1). In the remaining 22 patients, the CS catheter was appropriately placed (without fluoroscopy) using reconstructed LA geometry displayed on the CARTO 3 system. The CS catheter was directly visualized and subsequently maneuvered with the “cross-torqueback-and fourth” technique across the CTI to the CS. The placement of all catheters in the X+ group was uneventful. The double TS puncture was also

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accomplished successfully in both groups using ICE guidance and without acute complications. Acute PV isolation was ultimately achieved in all 80 patients, encircling both ipsilateral veins with a common wide circumferential ablation lesion. In four (10%) and two (5%) patients in the X− and X+ group, respectively, an episode of sustained AF was inducible with incremental pacing after PV isolation. In these patients, a mitral isthmus line and lines connecting both superior and inferior PVs were added. Block of conduction through the mitral isthmus was achieved in all six patients, while accomplishing complete posterior LA wall isolation failed in one patient in the X– group. A CTI ablation was performed on six (15%) patients in each group and bidirectional conduction block was achieved in all of them. The total procedure duration and RF application time in the X− and X+ groups were comparable (Table II). X-ray time and radiation dose were extremely low in the X− group compared to the standard procedure (5.6 ± 33 mGy/cm2 vs 3062 ± 1585 mGy/cm2 , P < 0.000001). There were no major procedure-related complications in any of the patients during the in-hospital stay and further follow-up. Minor complications included only larger femoral hematomas (exceeding human palm in area) in three patients of both groups, but none of the patients required surgery or any other intervention. The second control TEE examination was refused by some patients in both groups; therefore, only 36 and 33 patients in the X− and X+ groups, respectively, were available for detection of potential complications after catheter ablation. No significant PV narrowing was detected in any of the patients.

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Table II. Procedural Data

N PVI only PVI + CTI ablation PVI + LA lines PVI + CTI ablation + LA lines RF application time (seconds) X-ray time (minutes) Radiation dose (mGy/cm2 ) Procedural time (minutes)

X− Group

X+ Group

P

40 30 (75%) 6 (15%) 4 (10%) 0 (0%) 1785 ± 548 0.003 ± 0.016 5.6 ± 33 92.5 ± 22.9

40 33 (82.5%) 5 (12.5%) 1 (2.5%) 1 (2.5%) 1755 ± 450 3.0 ± 1.4 3062 ± 1585 99.9 ± 15.9

NS NS NS NS NS

Catheter Ablation of Atrial Fibrillation Using Zero-Fluoroscopy Technique: A Randomized Trial.

Recent advances in 3D mapping systems, such as simultaneous visualization of multiple catheters and contact force measurement, have allowed a signific...
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