International Journal of Cardiology 190 (2015) 338–343

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International Journal of Cardiology

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Catheter ablation of idiopathic ventricular tachycardia without the useof fluoroscopy☆

Filippo Lamberti a,⁎, Francesca Di Clemente a, Romolo Remoli a, Cesare Bellini a, Antonella De Santis a,Marina Mercurio b, Serena Dottori b, Achille Gaspardone a

a Department of Medicine, Cardiovascular Section, San Eugenio Hospital, Rome, Italyb Biosense Webster Italy, Johnson and Johnson Medical, Milan, Italy

☆ All authors take responsibility for all aspects of the rbias of the data presented and their discussed interpretat⁎ Corresponding author at: UOC di Cardiologia, Ospe

Umanesimo 10, 00144 Roma, Italy.E-mail address: filippo.lamberti@tin.it (F. Lamberti).

http://dx.doi.org/10.1016/j.ijcard.2015.04.1460167-5273/© 2015 Elsevier Ireland Ltd. All rights reserved

a b s t r a c t

a r t i c l e i n f o

Article history:

Received 7 January 2015Received in revised form 17 March 2015Accepted 16 April 2015Available online 17 April 2015

Keywords:Idiopathic ventricular tachycardiaNon-fluoroscopic catheter ablationRadiation riskIntracardiac echocardiographyElectro-anatomical mappingRadiofrequency

Background: Catheter ablation is the treatment of choice for many patients with idiopathic ventricular tachycar-dia (VT). Unfortunately, conventional catheter ablation is guided byfluoroscopy,which is associatedwith a smallbut definite radiation risk for patients and laboratory personnel. The aim of our study is to assess feasibility, suc-cess rate and safety of idiopathic VT ablation procedure performed without the use of fluoroscopy.Methods:Nineteen consecutive patients undergoing idiopathic VT ablation at our institution have been included.The ablation procedures were performed under the guidance of electroanatomical mapping (EAM) system andintracardiac echocardiography (ICE).Results: Nineteen patients (mean age 38.7 years) underwent ablation procedure for idiopathic VT. Twelve (63%)had outflow tract VT, 3 (18%) fascicular tachycardia, 2 (11%) peri-tricuspidal VT, 1 (5%) peri-mitral VT, and 1 (5%)lateral left free-wall VT. The mean procedural time was 170.2 ± 45.7 min. No fluoroscopy was used in anyprocedural phase. Acute success rate was 100%. No complication was documented in any patients. After amean follow up of 18 ± 4 months, recurrences occurred in 2 patients.

Conclusions: In our preliminary experience idiopathic VT ablationwithout the use offluoroscopywas feasible andsafe, using a combination of EAM and ICE. Success rate was excellent with no complication.

© 2015 Elsevier Ireland Ltd. All rights reserved.

1. Introduction

Catheter ablation is the treatment of choice for many patients withidiopathic ventricular tachycardia/premature ventricular contractions(VT/PVC). The success rate for this procedure is greater than 90% formost substrates. Conventional catheter ablation employing fluoroscopyis associatedwith a small but definite radiation risk for patients and lab-oratory personnel [1,2]. These risks are heightened in case of lengthyand multiple ablation procedures (eg, atrial fibrillation) and, in particu-lar, among vulnerable patients such as pediatric, obese, and pregnantpatients [3,4]. For complex/lengthy electrophysiology procedures, 1 hof fluoroscopy is associated with an increase in lifetime risk of fatal ma-lignancy of 0.07% for female and 0.1% formale patients [5]. Although theattributable risk seems small, it is important to recall that fluoroscopyexposure is additive and is not limited to the electrophysiology labora-tory. Emphasizing the importance of minimizing radiation exposureduring cardiac interventions, the American College of Cardiology has

eliability and freedom fromion.dale San Eugenio, P.le dell'

.

promoted the ALARA principle: keep fluoroscopic exposure to a level“as low as reasonably achievable” [6]. The advent of electroanatomicmapping (EAM) systems, that are able to map cardiac chambers and si-multaneously visualizemultiple catheters, has allowed to lower the useof fluoroscopy during electrophysiology procedures [7,8]. Further fluo-roscopy reduction, or even elimination, can be obtained combiningthese techniques with other imaging modalities such as intracardiacechocardiography (ICE) or transesophageal echocardiography (TEE).Several authors have reported their experience with ablation of supra-ventricular tachycardia substrates on the right and left sides of theheart without the use of fluoroscopy with a success rate overlappingthat of standard procedures and with a very low incidence of complica-tions [9–12]. Even in more “complex procedures” such as atrial fibrilla-tion ablation (AF) a non-fluoroscopic approach was demonstrated to befeasible and safe, combining ICE and EAM system [13].

In the present study, we report our experience of attempting tocompletely eliminate fluoroscopy during catheter ablation procedurefor idiopathic VT, using EAM in conjunction with ICE.

2. Methods

From January 2011 a “zero-fluoroscopy” catheter ablation programwas started at our center including procedures for supraventricular

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and ventricular arrhythmias. Nineteen consecutive patients with idio-pathic VT/PVC and candidate to catheter ablation were treated with afluoroless approach and included in this report. Written informed con-sent was obtained from patients or their parents. The study protocolconforms to the ethical guidelines of the 1975 Declaration of Helsinkias reflected in a priori approval by the institution's human researchcommittee.

Antiarrhythmic drugs were discontinued before catheter ablationbased on their half-time.

All the procedures were performed under conscious sedation usingbolus of fentanyl and midazolam. Since the beginning of the procedure,X ray apparatus was left off and all of the medical and nursing staff didnot wear lead aprons.

2.1. Catheter positioning and electrophysiological study

After standard femoral access, a 3.5-mm externally irrigated radio-frequency (RF) ablation catheter (Thermocool SF; Biosense-Webster,Inc., Diamond Bar, CA) was advanced into the inferior vena cava (IVC)under EAM system guidance (CARTO 3, Biosense-Webster, Inc.,Diamond Bar, CA). Three dimensional (3D) geometric contours of theIVC were created by sweeping the catheter tip while advancing it upto the initial appearance of atrial electrograms that denoted the junctionbetween the IVC and the right atrium (RA). Any difficulties in catheteradvancementwere overcomewith a geometric acquisition of the trajec-tory of the catheter through the venous system (Fig. 1, panel A). Ulti-mately, the catheter was advanced to the RA in order to delineate itsborder, tagging the areawhere a His deflectionwas recorded and repro-ducing in detail the tricuspidal annulus. In patients with outflow tractVT the coronary sinus (CS) was reconstructed up to its distal portion.Once the 3D shell of the RA was obtained, two quadripolar catheterswere advanced in the RA and positioned respectively in the His bundleregion and in the right ventricle (RV) using the right and left anterioroblique views of the EAM system (Movie 1; Fig. 1, panel B). In thesamemanner, a decapolar deflectable catheter was advanced in the dis-tal CS if required (Movie 2; Fig. 1, panel B). Standard ventricular stimu-lationwas performed to induce VT. Isoproterenol infusion up to 5 γ/minwas used if necessary.

Fig. 1. Panel A shows the anteroposterior view of the 3 D reconstruction the RA and the IVC usvertently engaged (white arrow), are created by sweeping the ablation catheter tip. As the catseptal aspect of the RA is probed, the CS is engaged and then reconstructed up to its distal poPanel B shows the right (on the left) and left (on the right) anterior oblique views of the 3D reHis bundle region (yellow catheter) and in the right ventricle (blue catheter) and the multipomovement, two videos are included as an online supplement (Movies 1 and 2); these videos s

2.2. ICE chamber reconstruction

Then a 10-Fr ICE catheter (Soundstar, Biosense-Webster, Inc., Dia-mond Bar, CA) was inserted through the left femoral vein, advancedup to the RA and then rotated and manipulated in order to visualizemultiple echo sections. Sequential ICE contours of the right and/or theleft ventricle were acquired in order to create a 3D shell of the chambersusing the CartoSound™ module (Biosense-Webster, Inc., Diamond Bar,CA) that allows the integration of ICE and EAM system 3Dmaps. Partic-ularly, when required, detailed imaging of the right ventricular outflowtract (RVOT), pulmonary valve, aortic root, aortic valve and left ventric-ular outflow tract (LVOT)was obtained. The origin of the coronary arter-ies was marked on the reconstructed 3D echo shell when necessary.

2.3. Mapping and ablation

The 3D ICE shells of the ventricles were used for catheter manipula-tion in order to create a 3D electro-anatomic activation map focused onthe area of interest (Fig. 2). In case of outflow tract VT, EAMof both LVOTand RVOTwas performed. Moreover, in this setting, intracardiac signalsfrom the distal CS were always recorded. Left ventricle (LV) wasmapped, when required, with retrograde trans-aortic approach. In de-tail 3D shell of the aorta was obtained while advancing the ablationcatheter in the vessel from the femoral artery. Once the catheterreached the aortic arch, its distal portionwas looped and then advancedin the aortic root, to avoid the engagement of the left main coronary ar-tery. Moreover, at this point, the direct visualization of the catheter en-abled by ICE was used in order to safely cross the valve [14].

The electro-anatomic activation map was obtained annotating theearliest local activation during PVC or VT. Maximum voltage value ofsurface ECG was selected as reference. Local earliest activation com-bined with sharp negative deflection (QS) in the unipolar derivationand optimal pacemapping (12/12 leads)was used to guide the ablation.Abnormal Purkinje potentials (PP) in sinus rhythmor during ventriculartachycardia were used to guide the ablation of fascicular VT (Fig. 3); ifidiopathic left ventricular tachycardia (ILVT) was not inducible or sus-tainable, a linear lesion was created at the level of the posterior fascicle[15] or, if necessary, left posterior fascicle block was targeted [16].

ing the CARTO 3 system. Geometric contours of the IVC, including various branches inad-heter is manipulated in the RA and SVC, the RA geometry becomes evident. As the lowerrtion. Yellow tag points represent the area where the His bundle deflection is recorded.construction of the RA, with the two quadripolar catheters positioned respectively in thelar catheter (red catheter) in the coronary sinus. To better appreciate real-time catheterhow the diagnostic catheters positioning.

Fig. 2.Mapping and ablation of left ventricle outflow tract tachycardia, performed using the 3D echo-based reconstruction in a right anterior oblique view as catheter manipulation guid-ance, instead of fluoroscopy. The Soundstar catheter tip (ICE) is located in the right atrium. The echo reconstruction of the right ventricle (RV) is showed as mesh, while that of the leftventricle (LV) is visualized in transparency. The activation electroanatomic map was performed during ventricular tachycardia, only in the area of interest. The earliest activationsite (asterisk on the endocardial recordings) was located just below the aortic cusp, where the tip of the ablation catheter is located. Red dots refer to ablation points. Ao= aorticroot; PA = pulmonary artery.

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The RF generator (Stockert, Biosense Webster) was set to deliver RFenergy up to 35W; the temperature was not permitted to exceed 41 °C.Energy was titrated to achieve an impedance drop of 10–15 Ω. RF wasdelivered during VT or PVC. After ablation, a complete ventricular stim-ulation protocol in basal condition and during and after intravenousisoproterenol (up to 5 γ/min) was performed in order to assess PVC/VT induction.

3. Results

3.1. Patient characteristics

In this study 19 patients (11 males, mean age 38.7 yrs, range 16–81 yrs) with idiopathic VT candidate to catheter ablation, were treatedwith fluoroless approach. Clinical data are reported in Table 1.

The VT/PVC types were: RVOT PVC/VT in 8 (42%) patients, LVOT VT/PVC in 4 (21%) patients, ILVT in 3 (16%) patients, peri-tricuspidal PVC/VT in 2 (11%) patients, peri-mitral PVC/VT in 1 (5%) patient and lateralleft free-wall VT in the remaining patient (5%).

In detail, out of the 8 RVOT VT/PVC the ablation site was localized atthe antero-septal (leftward) sub-valvular region of the RVOT in 6 pa-tients, at the anterior region in 1 patient and at the posterior region inthe last patient. Out of the 4 LVOT VT/PVC, 2 were localized atthe left aortic cusp (Fig. 4), 1 at the right aortic cusp and 1 just belowthe aortic valve. The two peri-tricuspidal PVC/VT were localized at thepostero-septal (5 o'clock) and antero-lateral (11 o'clock) aspect of thetricuspidal area, respectively.

3.2. Procedural data

The mean procedural time was 170.2 ± 45.7 min. Other proceduralparameters and further details can be found in Table 2. A mean of 55 ±10 ICE contours was acquired to obtain the 3D echo map, requiring a

mean time of 16.5 ± 7 min. Activation mapping times were mainly in-fluenced by the frequency of PVC or by VT inducibility.

All the diagnostic, ICE and ablation catheters were easily maneu-vered and positioned, without the use of fluoroscopy. Retrogradetransaortic approach was also fluoroless performed, without any diffi-culties or inadvertent engagement of the left main coronary artery,guided by the pre-acquired 3D echo shell of the ascending aorta andby the real-time visualization of the ablation catheter both virtualwith the EAM system and direct with the ICE [14]. Indeed, no fluorosco-py was used in any procedural phase.

Acute procedural success was obtained in all the patients. No com-plication was documented in any patient.

3.3. Follow-up

After a mean follow-up of 18 ± 4 months the success rate was 89%(17/19). Recurrences were documented in 1 patient with peri-tricuspid PVC/VT and in 1 patient with ILVT. This latter patient was sub-mitted to a new fluoroless procedure in which posterior fascicle block-ade was targeted due to non-sustainable VT. After six months offollow-up no recurrences were documented in this patient.

4. Discussion

4.1. Main findings

The present study demonstrates the safety and the feasibility ofperforming all of the various phases of an idiopathic VT ablation proce-dure without the use of fluoroscopy: (1) EAM system-guided catheteradvancement and positioning within the heart, (2) ICE reconstructionof the ventricles, and (3) VT mapping and ablation. With our non-fluoroscopic approach we were able to reduce radiation to 0 in all theprocedures for different substrates of idiopathic VT. These results wereachievedwith an excellent acute success rate andwithout complications.

Fig. 3. A screenshot from the Carto 3/CartoSound working station during idiopathic fascicular left ventricular tachycardia ablation. On the right panel, the activation map of theleft ventricular uppermid-septum performed during fascicular tachycardia is superimposed on the intracardiac echocardiography (ICE) based 3D reconstruction of the left ventricle. Theultrasonic fan shows the real time ICE images of the section of aortic root (Ao), pulmonary artery (PA) and RVOT. Ablation points aremarked in red and the corresponding electrograms aredisplayed on the left panel (white electrograms), showing a sharp Purkinje potential (arrows) before the ventricular electrogram and a diastolic potential (asterisks) after the ventricularelectrocardiogram. Blue tags indicate the left anterior fascicle.

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4.2. Previous studies

Radiation exposure has become an important issue in interventionalprocedures. In fact, the American College of Cardiology recommendsthat all catheterization laboratories adopt the principles of “ALARA”(radiation doses “as low as reasonably achievable”) [6]. These guidelines

Table 1Patients clinical data.

Pts Age Sex Comorbidities EF % VT/PVC Drugs

1 67 M Hypertension 58 LVOT None2 81 M Hypertension, dyslipidemia 61 RVOT Sotalol3 60 M None 58 PTVT Amiodarone4 41 M None 55 RVOT Propafenone5 39 F None 51 RVOT None6 48 M None 66 LVOT Flecainide7 43 F None 58 LFWVT Propafenone8 20 M None 68 ILVT Betablocker9 38 F None 55 ILVT Betablocker10 36 F None 60 RVOT Betablocker11 20 M None 66 ILVT Betablocker12 41 M None 55 LVOT Propafenone13 26 F None 64 RVOT Amiodarone14 28 F None 66 RVOT Flecainide15 17 M None 58 PMTV Betablocker16 16 M None 66 RVOT Flecainide17 22 F None 52 LVOT Flecainide18 42 F None 66 RVOT Betablocker19 51 M Hypertension 64 PTVT None

ILVT= idiopathic left VT; LFWVT= left free wall VT; LVOT= left ventricle outflow tract;PMVT=peri-mitral VT; PTVT=peri-tricuspidal VT; RVOT= right ventricle outflow tract.

are intended for the protection of both the patient and the staff. Conse-quently there is increasing interest in methods to minimize radiationexposure during catheter procedures. Many authors have shown thatwe have the technology to achieve this aim at least in supraventriculararrhythmias including AF ablation [9,10,12,17]. On the other side, toour knowledge, there is just one study focused on fluoroscopy reductionduring idiopathic VT ablation procedures [13], enrolling a pediatricpopulation only. Using the Ensite NavX system, the authors showed asignificant reduction in radiation exposure, but fluoroscopy was notcompletely avoided.

4.3. Present study

Our experience suggests that a total fluoroless approach to idiopath-ic VT ablation is feasible in a wide variety of location of arrhythmia ori-gin, using a combination of the EAM system and ICE. The CARTO 3system allowed us to advance the various catheters through the vascu-lar system, once the 3D contours of the IVC and RA have been createdwith the ablation catheter (Fig. 1). It also provided us the possibility tovisualize the ICE catheter and, by this, tomove it in the cardiac chambers(RA and RV) without fluoroscopy. The true adjunctive chapter of theprocedure is the creation of a 3D echo reconstruction of the cardiacstructures from the sequentially acquired contours of the 2D echo slices,by the CartoSoundmodule. Although this step claims for a possible pro-longation of the procedural time if compared to standard approach [18],there are many advantages in utilizing this technique. In fact, it allows:1) a real time and direct visualization of the ablation catheter, its tissuecontact and stability; 2) structural and functional detailed real time im-aging of all the cardiac and some extracardiac structures; 3) a 3D

Fig. 4.Mapping and ablation of a LVOT VT. Electroanatomic activation map of the aortic cusps during ventricular tachycardia (VT). Ablation catheter tip (arrow) is placed on the earliestactivation point (red according to the color code). Local electrogram shows a presystolic potential (asterisk) on the bipolar recording while a QS morphology is showed on the unipolarrecordings. A decapolar catheter (the blue one) is located distally in the coronary sinus (CS). The echo fan clearly shows the real time position of the ablation catheter tip in the aortic root(Ao). The CartoSound system allows the automatic detection of the ablation catheter tip depicted by green contours (star). PA = pulmonary artery.

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chamber reconstruction used for merging, avoiding preliminary imag-ing such as computer tomography and consequently further X-ray ex-posure; and 4) early identification of complication such as pericardialeffusion or tamponade.

In our experience, also, the frequency or inducibility of PVC/VT rep-resented one of themain difficulties encountered during idiopathic ven-tricular arrhythmia ablation procedures. On the contrary catheter

Table 2Procedure data.

Pts VT IVC-RAgeometry(min)

Catheterpositioning(min)

ICEmapping(min)

VTmapping(min)

1 LVOT 3 5 28 232 RVOT 7 1.5 12 343 PTVT 7 2 10 324 RVOT 5 2 8 255 RVOT 6.5 3 24.5 156 LVOT 4.5 3 12.5 18.57 LFWVT 4 1.5 32.5 88 ILVT 6.5 3 18.5 239 ILVT 7 3 22 2510 RVOT 4 1 14 2611 ILVT 8.5 1.5 12 1812 LVOT 9 4.5 26 1213 RVOT 4 1 11 3314 RVOT 4 2 9.5 2515 PMTV 8 2 17.5 716 RVOT 6.5 1 12 2717 LVOT 5 3 18.5 1718 RVOT 7 2.5 10 2119 PTVT 7 2 15 8Tot 5.9 ± 1.7 2.3 ± 1.1 16.5 ± 7 20.9 ± 8.2

ILVT= idiopathic left VT; LFWVT= left free wall VT; LVOT= left ventricle outflow tract;PMVT=peri-mitral VT; PTVT=peri-tricuspidal VT; RVOT= right ventricle outflow tract.

navigation for mapping and ablation of different arrhythmogenic sub-strates did not present any particular difficulties once the anatomicshell was available, even when a retrograde transaortic approachhas been required. In fact, the reliablemodel of 3D echo chamber recon-struction is useful to know the anatomy in advance, so that the operatorcould be more confident in manipulating catheters without direct fluo-roscopy visualization. It could be one of the possible explanations of thetotal elimination of fluoroscopy reported in our study, in contrast toOzyilmaz et al. [19], that obtained only a reduction of fluoroscopy in id-iopathic VT ablation, using the Ensite NavX system. Indeed, until today,this EAM system has not allowed 3D ICE reconstruction and integrationof explored chamber with the relative activation map.

4.4. Clinical significance

This series demonstrates the feasibility, safety and efficacy offluoroless idiopathic VT ablation procedures. We believe that this ap-proach should be considered for all the EP procedures and mandatoryfor certain vulnerable patient populations such as children andpregnantwomen. In addition, there are increasing data that obese patients mayrepresent a similarly vulnerable population in which to consider afluoroless procedure [4]. If it can be reasonably argued that the radiationexposure of the patient during a single conventional procedure is notthat high, it should be considered that the patient could also be exposedto radiation outside EP laboratory and that the physician, nursing, andtechnical staff are exposed to X-rays on a daily basis. Unfortunately,the radiation risk is cumulative and lifelong, leading to potentialnegative effects such as cataracts, reproductive system damage andma-lignancies [20–22]. In addition, there are occupational health implica-tions related to the impact of the lead apparel worn to reduce thisexposure. For the procedures performed in our series, the physician,

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nursing, and technical staff did not wear any lead apparel—a fact thatcertainly was qualitatively a more pleasant experience for everyone.

The increased cost of the fluoroless procedure compared with theconventional one is probably the main reason why navigation systemsare not routinely used. It is true that the financial cost must be anywaybalanced against the benefits of their use.

5. Limitations

This study presents several limitations. It is not a randomized trialand the population size is small. It therefore does not have the statisticalpower to conclude safety or efficacy of this new approach. In any case itis noteworthy that therewere nomajor complications experienced dur-ing this study. Moreover we do not have a control population. We didnot use catheterswith contact force sensors thatmay increase the safetyof their manipulation without fluoroscopy, even if a direct visualizationof the ablation catheter by ICE provided us some information about tis-sue contact. None of the patients in this study required a transseptalpuncture and/or epicardial approach, a situation that for sure requiresX-ray visualization during epicardial puncture and for the assessmentof the coronary artery tree. Moreover, none of the ablation site wasclose to the coronary ostia, a situation that may require coronary angi-ography. Finally, all of the procedures in this series were performed bya single experienced operator. Additional experienceswithmultiple op-erators are necessary to assess the global clinical safety, efficacy, andfeasibility of fluoroless idiopathic VT ablation.

6. Conclusion

Idiopathic VT ablation can be performed without the use of fluoros-copy. This not only has important clinical implications for pediatric,pregnant and obese patients but also raises the issue of whether weshould be striving for themost literal adaptation of the policy of ALARA.

Supplementary data to this article can be found online at http://dx.doi.org/10.1016/j.ijcard.2015.04.146.

Conflict of interest

None.

Acknowledgment

None.

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