Catheter location, tracking, cardiac chamber geometry creation, and ablation using cutaneous patches

Electroanatomic mapping in athletes: Why and when. An expert opinion paper from the Italian Society of Sports Cardiology

Three-dimensional electroanatomical mapping (EAM) has the potential to identify the pathological substrate underlying ventricular arrhythmias (VAs) in different clinical settings by detecting myocardial areas with abnormally low voltages, which reflect the presence of different cardiomyopathic substrates. In athletes, the added value of EAM may be to enhance the efficacy of third-level diagnostic tests and cardiac magnetic resonance (CMR) in detecting concealed arrhythmogenic cardiomyopathies. Additional benefits of EAM in the athlete include the potential impact on disease risk stratification and the consequent implications for eligibility to competitive sports. This opinion paper of the Italian Society of Sports Cardiology aims to guide general sports medicine physicians and cardiologists on the clinical decision when to eventually perform an EAM study in the athlete, highlighting strengths and weaknesses for each cardiovascular disease at risk of sudden cardiac death during sport. The importance of early (preclinical) diagnosis to prevent the negative effects of exercise on phenotypic expression, disease progression, and worsening of the arrhythmogenic substrate is also addressed.

From near-zero to zero fluoroscopy catheter ablation procedures

AIMS

The use of electroanatomical mapping (EAM) systems can reduce radiation exposure (RX) and it can also completely eliminate the use of RX. Radiation exposure related to conventional radiofrequency ablation procedures can have a stochastic and deterministic effect on health. The main aim of this study was to evaluate the safety and feasibility of an entirely nonfluoroscopic approach to catheter ablation (CA) using EAM CARTO3.

METHODS

In 2011 we started an RX-minimization programme in all procedures using the CARTO system with the deliberate intention to not resort to the aid of RX unless strictly necessary. We divided procedures into two groups (group 1: from 2011 to 2013; group 2: from 2014 to 2017). The only exclusion criteria were the need for transseptal puncture, and nonidiopathic ventricular tachycardia (VT).

RESULTS

From a total of 525 procedures, we performed CA entirely without RX in 78.5% of cases. From 2011 to 2013, we performed CA without RX in 38.5% of cases; from 2014 to 2017, we performed 96.2% of cases with zero RX. The use of RX was significantly reduced in group 2 (group 2: 1.4 ± 19.6 seconds vs group 1: 556.92 ± 520.76 seconds; P < .001). These differences were irrespective of arrhythmia treatment. There were no differences between the two groups in acute success, complications, or duration of procedures.

CONCLUSION

CA of supraventricular tachycardia and VT entirely without RX, guided by the CARTO system, is safe, feasible, and effective. After an adequate learning curve, CA can be performed entirely without RX.

Near zerO fluoroscopic exPosure during catheter ablAtion of supRavenTricular arrhYthmias: the NO-PARTY multicentre randomized trial

AIMS

Aim of this study was to compare a minimally fluoroscopic radiofrequency catheter ablation with conventional fluoroscopy-guided ablation for supraventricular tachycardias (SVTs) in terms of ionizing radiation exposure for patient and operator and to estimate patients' lifetime attributable risks associated with such exposure.

METHODS AND RESULTS

We performed a prospective, multicentre, randomized controlled trial in six electrophysiology (EP) laboratories in Italy. A total of 262 patients undergoing EP studies for SVT were randomized to perform a minimally fluoroscopic approach (MFA) procedure with the EnSiteTMNavXTM navigation system or a conventional approach (ConvA) procedure. The MFA was associated with a significant reduction in patients' radiation dose (0 mSv, iqr 0-0.08 vs. 8.87 mSv, iqr 3.67-22.01; P < 0.00001), total fluoroscopy time (0 s, iqr 0-12 vs. 859 s, iqr 545-1346; P < 0.00001), and operator radiation dose (1.55 vs. 25.33 µS per procedure; P < 0.001). In the MFA group, X-ray was not used at all in 72% (96/134) of cases. The acute success and complication rates were not different between the two groups (P = ns). The reduction in patients' exposure shows a 96% reduction in the estimated risks of cancer incidence and mortality and an important reduction in estimated years of life lost and years of life affected. Based on economic considerations, the benefits of MFA for patients and professionals are likely to justify its additional costs.

CONCLUSION

This is the first multicentre randomized trial showing that a MFA in the ablation of SVTs dramatically reduces patients' exposure, risks of cancer incidence and mortality, and years of life affected and lost, keeping safety and efficacy.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT01132274.

3D localization of electrophysiology catheters from a single x-ray cone-beam projection

PURPOSE

X-ray images allow the visualization of percutaneous devices such as catheters in real time but inherently lack depth information. The provision of 3D localization of these devices from cone beam x-ray projections would be advantageous for interventions such as electrophysiology (EP), whereby the operator needs to return a device to the same anatomical locations during the procedure. A method to achieve real-time 3D single view localization (SVL) of an object of known geometry from a single x-ray image is presented. svl exploits the change in the magnification of an object as its distance from the x-ray source is varied. The x-ray projection of an object of interest is compared to a synthetic x-ray projection of a model of said object as its pose is varied.

METHODS

svl was tested with a 3 mm spherical marker and an electrophysiology catheter. The effect of x-ray acquisition parameters on svl was investigated. An independent reference localization method was developed to compare results when imaging a catheter translated via a computer controlled three-axes stage. svl was also performed on clinical fluoroscopy image sequences. A commercial navigation system was used in some clinical image sequences for comparison.

RESULTS

svl estimates exhibited little change as x-ray acquisition parameters were varied. The reproducibility of catheter position estimates in phantoms denoted by the standard deviations, (σ(x), σ(y), σ(z)) = (0.099 mm,  0.093 mm,  2.2 mm), where x and y are parallel to the detector plane and z is the distance from the x-ray source. Position estimates (x, y, z) exhibited a 4% systematic error (underestimation) when compared to the reference method. The authors demonstrated that EP catheters can be tracked in clinical fluoroscopic images.

CONCLUSIONS

It has been shown that EP catheters can be localized in real time in phantoms and clinical images at fluoroscopic exposure rates. Further work is required to characterize performance in clinical images as well as the sensitivity to clinical image quality.

ELECTROLOC: A SIMPLE, FAST AND ACCURATE SYSTEM FOR LOCALIZATION OF ENDOCARDIAL CATHETERS

Accurate positioning of endocardial catheters inside cardiovascular structures is crucial in electrophysiology (EP) procedures. Improvements in cardiac mapping are required for a better understanding and treatment of arrhythmias. The proposed Electroloc system is a simple, fast and accurate method for endocardial catheters localization. The key features of Electroloc are the use of conventional EP catheters and the simple data processing for providing localization. Electroloc is able to locate any conventional EP mapping catheter with respect to a noncontact EP catheter used as reference, by sequentially passing a sub-threshold current between the mapping electrode (ME) of the mapping catheter and each electrode of the reference catheter. This creates different potential gradients across the reference catheter used to compute two spatial coordinates (horizontal and vertical coordinates) intended for positioning the ME in the cardiac chamber. In vitro experiments demonstrated that Electroloc is a reliable and sensitive system for localizing the ME with a spatial resolution of 2 mm in the vertical localization and of 5 mm in the horizontal localization. Further studies will be required to improve Electroloc accuracy and to extend its sensitivity range.

A new electrophysiology era: zero fluoroscopy

Catheter ablations are traditionally performed under fluoroscopic guidance. Besides other peri-interventional risks, radiation exposure should be considered for its stochastic and deterministic effects on health. These effects are cumulative and lifelong and raise great concerns especially in the younger population. A document of the American College of Cardiology recommends that all catheterization laboratories adopt the principles of 'ALARA' (radiation doses 'As Low As Reasonably Achievable'), making radiation reduction an ethical issue. In electrophysiology, thanks to the recent development of electroanatomic navigation systems, we are witnessing the birth of a new era in which almost all arrhythmias may be treated without the use of fluoroscopy. In the present review, we start by describing risks to health due to radiation exposure for conventional transcatheter ablations and we continue by reporting the current state of art of the zero fluoroscopy approach.

Use of a novel endoscopic catheter for direct visualization and ablation in an ovine model of chronic myocardial infarction

BACKGROUND

Defining the arrhythmogenic substrate is essential for successful ablation of scar-related ventricular tachycardia. The visual characteristics of endocardial ischemic scar have not been described in vivo. The goal of this study was (1) to quantify the visual characteristics of normal tissue, scar border zone, and dense scar in vivo with the use of a novel endoscopic catheter that allows direct endocardial visualization and (2) to correlate visual attributes of myocardial scar with bipolar voltage.

METHODS AND RESULTS

Percutaneous transient balloon occlusion (150 minutes) of the mid left anterior descending coronary artery was performed in an ovine model. Animals survived for 41.5±0.7 days. Detailed bipolar voltage maps of the left ventricle were acquired with the use of NavX. Video snapshots of the endocardium were acquired at sites distributed throughout the left ventricle. Visual tissue characteristics of normal (>1.5 mV), border (0.5-1.5 mV), and dense scar (<0.5 mV) were quantified with the use of image processing. Radiofrequency lesions (10-20 W, 30 seconds) were delivered under direct visualization. Mean white-threshold pixel area was lowest in normal tissue (189 969±41 478 pixels(2)), intermediate in scar border zone (255 979±36 016 pixels(2)), and highest in dense scar (324 452±30 152 pixels(2); P<0.0001 for all pairwise comparisons). Tissue whiteness, characteristic of scar, was inversely correlated with bipolar voltage (P<0.0001). During radiofrequency lesions, there was a significant increase in white-thresholded pixel area of the visual field after ablation (average increase, 85 381±52 618 pixels(2); P<0.001).

CONCLUSIONS

Visual characteristics of chronic infarct scar in vivo observed with the use of a novel endoscopic catheter correlate with bipolar electrogram voltage. Irrigated radiofrequency lesions in normal endocardial tissue and postinfarction zone can be visualized and quantified with the use of image processing. This technology shows promise for visually based delivery of radiofrequency lesions for the treatment of scar-based ventricular tachycardia.

Retrograde fast pathway ablation with the EnSite NavX mapping system for slow-fast atrioventricular node reentrant tachycardia and a prolonged PR interval during sinus rhythm

An 84-year-old male had experienced palpitations. He was transported to our hospital for treatment of palpitations. A 12-lead electrocardiogram (ECG) showed regular tachycardia with a wide QRS complex of 153 bpm, and the P wave was not clear. The ECG after the tachycardia stopped showed a sinus rhythm, and there was a prolonged PR interval of 312 ms and complete right bundle branch block. We recorded a prolonged AH interval (235 ms) in electrophysiology study (EPS). As for the St-A interval (185 ms) by consecutive pacing from the right ventricular apex, it was short in comparison with the anterograde conduction. As a result of detailed EPS, we diagnosed the tachycardia as slow-fast atrioventricular nodal reentrant tachycardia. The anterograde conduction depended on the slow pathway (SP), and the fast pathway (FP) was considered to have only retrograde conduction. It was thought that a complete atrioventricular block been caused by the SP ablation. Therefore we carried out FP ablation with three-dimensional computed tomography and the EnSite NavX mapping system (St. Jude Medical, St Paul, MN, USA), which was superior in space resolution power, and were able to effect a radical cure without complications.

Right ventricular substrate mapping using the Ensite Navx system: Accuracy of high-density voltage map obtained by automatic point acquisition during geometry reconstruction

BACKGROUND

Contact point-to-point electroanatomic mapping (Pt-Map) is a validated tool to evaluate right ventricular (RV) substrate. When using the EnSite NavX system (St. Jude Medical, St Paul, Minnesota), geometry reconstruction by dragging the mapping catheter (Geo-Map) allows for quicker acquisition of a large number of points and better definition of anatomy, but it is not validated for substrate mapping.

OBJECTIVE

This study evaluates the feasibility and accuracy of Geo-Map.

METHODS

Thirteen patients (mean age 38 +/- 12 years) with RV arrhythmias and an apparently normal heart underwent cardiac magnetic resonance imaging (MRI), Pt-Map, and Geo-Map. The 2 maps were compared in terms of mapping procedural time, radiation time, and total number of points acquired. We finally compared the number and characteristics of low-potential areas on each patient's Pt-Map, Geo-Map, and cardiac MRI.

RESULTS

Geo-Map required significantly shorter mapping and radiation times in comparison to Pt-Map (12.4 +/- 4.6 vs. 31.9 +/- 10.1 and 5.8 +/- 2.1 vs. 12.1 +/- 3.9, P <.001). Furthermore, Geo-Map was based on a significantly higher density of points in comparison to Pt-Map (802 +/- 205 vs. 194 +/- 38, P <.001). Taking into consideration the total number of RV regions analyzed, the Pt-Map and Geo-Map disagreed in 2 of 65 (3%) regions (P = NS), which only Geo-Map identified as low-potential areas and indeed corresponded to wall motion abnormalities on MRI.

CONCLUSION

Voltage maps obtained through RV geometry acquisition have accuracy comparable to that of conventional point-by-point mapping in detecting low-voltage areas, have a good correlation with MRI wall motion abnormalities, and allow a significant reduction in procedural time and x-ray exposure.

Computed tomography model-based treatment of atrial fibrillation and atrial macro-re-entrant tachycardia

Aims

Accurate orientation within true three-dimensional (3D) anatomies is essential for the successful radiofrequency (RF) catheter ablation of atrial fibrillation (AF) and atrial macro-re-entrant tachycardia (MRT). In this prospective study, ablation of AF and MRT was performed exclusively using a pre-acquired and integrated computed tomography (CT) image for anatomical 3D orientation without electro-anatomic reconstruction of the left atrium (LA).

Methods and results

Fifty-four consecutive patients suffering from AF (n = 36) and/or MRT (n = 18) underwent RF catheter ablation. A 3D CT image was registered into the NavX-Ensite system without reconstruction of the atrial chamber anatomy. The quality of CT alignment was assessed and validated according to fluoroscopy information, electrogram characteristics, and tactile feedback at 31 pre-defined LA control points. The ablation of AF as well as mapping and ablation of MRT was performed within the 3D CT anatomy. In all patients, mapping and ablation could be performed without the reconstruction of the respective atrial chamber anatomy. The overall CT alignment was highly accurate with true surface contact in 90% (84%; 100%) of the control points. Complete isolation of all pulmonary vein (PV) funnels was achieved in 35 of 36 patients (97%) with AF. In patients with persistent AF (n = 11), additional isolation of the posterior LA (box lesion) and the placement of a mitral isthmus line were performed. The MRT mechanisms were as follows: around a PV ostium (n = 6), perimitral (n = 4), through LA roof (n = 5), septal (n = 2), and around left atrial appendage (n = 1). After a follow-up of 122 ± 33 days, 22/25 (88%) patients with paroxysmal AF, 8/11 (73%) with persistent AF, and 16/18 (89%) with MRT remained free from arrhythmia recurrences.

Conclusion

For patients with AF and MRT, our study shows the feasibility of successful placement of complex linear ablation line concepts guided by an integrated 3D image anatomy alone rather than catheter-based virtual chamber surface reconstructions.

Use of three-dimensional catheter guidance and trans-esophageal echocardiography to eliminate fluoroscopy in catheter ablation of left-sided accessory pathways

BACKGROUND

Newer technologies such as three-dimensional mapping and echocardiography can decrease x-ray exposure during catheter ablation. Many right-sided tachycardias can now be ablated without fluoroscopy. Left-sided tachycardias, however, have not yet been ablated using a zero fluoroscopy approach.

OBJECTIVE

This study sought to examine the utility of trans-esophageal echocardiography (TEE) in providing adequate imaging as an alternative to fluoroscopy for transseptal puncture. When combined with NavX guidance (St. Jude Medical, St. Paul, MN, USA), fluoroscopy may not be necessary.

METHODS

Ten pediatric patients with supraventricular tachycardia (SVT) had accessory pathways mapped to the left side. Right atrial and coronary sinus geometries were created using NavX. Once a left-sided pathway was confirmed, a transseptal puncture was performed. A guide wire was placed in the SVC and confirmed by TEE. A transseptal sheath and dilator were advanced over the wire and positioned with TEE guidance so that the tip of the dilator was tenting the fossa ovalis. A transseptal needle was advanced across the fossa. Left atrial location of the needle tip was confirmed on TEE by saline contrast injection. The sheath and dilator were advanced over the needle with continuous pressure monitoring and TEE. Once the sheath was appropriately positioned, the ablation was completed using NavX guidance.

RESULTS

All patients had acutely successful ablations and none required the use of fluoroscopy. Number of cryo lesions ranged from five to 19, with a mean of 9. Mean procedure time was 4.4 hours, with a range of 3.2 hours to 7.2 hours. There were no complications. One patient had recurrence.

CONCLUSIONS

Three-dimensional mapping combined with TEE shows potential for eliminating fluoroscopy use during catheter ablation.

Small or large isolation areas around the pulmonary veins for the treatment of atrial fibrillation? Results from a prospective randomized study

BACKGROUND

Pulmonary vein (PV) isolation is a promising new treatment for atrial fibrillation (AF). We hypothesized that isolation of large areas around both ipsilateral PVs with verification of conduction block is more effective than the isolation of each individual PV.

METHODS AND RESULTS

A total of 110 patients, 67 with paroxysmal AF and 43 with persistent AF, were randomly assigned to undergo either isolation of each individual PV or isolation of large areas around both ipsilateral PVs. The isolation of each individual PV was an electrophysiologically guided, ostial segmental ablation with a 64-pole basket catheter or a 20-pole circular mapping catheter (group I). Isolation of large areas was performed around the 2 ipsilateral veins with a nonfluoroscopic navigation system and a circular 20-pole mapping catheter for verification of conduction block (group II). In both groups, an irrigated-tip ablation catheter (25 to 35 W) was used to achieve complete isolation. Procedure and ablation times were longer in group II, whereas fluoroscopic time was significantly shorter (P < or = 0.001). After a follow-up period of 15+/-4 months, 27 patients in group I (49%) and 37 patients in group II (67%) remained free of symptoms of AF and had no AF or atrial flutter during repetitive Holter monitoring without antiarrhythmic drug treatment after a single procedure (P < or = 0.05).

CONCLUSIONS

The rate of success was significantly higher and fluoroscopy times were significantly lower in the group with large isolation areas around both ipsilateral PVs than in those who underwent individual PV isolation.

Catheter motion during atrial ablation due to the beating heart and respiration: Impact on accuracy and spatial referencing in three-dimensional mapping

BACKGROUND

The accuracy of three-dimensional mapping systems is affected by cardiac contraction and respiration.

OBJECTIVE

The study sought to determine relative motion of cardiac and thoracic structures to assess positional errors and guide the choice of an optimized spatial reference.

METHODS

Motion of catheters placed at the coronary sinus (CS), pulmonary vein (PV) ostia, left atrial (LA) isthmus and roof, cavotricuspid isthmus (CTI), and right atrial appendage (RAA) were recorded for 30 patients using Ensite-NavX. The right subclavian vein, left brachiocephalic vein, azygos vein, pulmonary arteries, and a static reference were included. The displacement from a mean position was calculated for each pair of sites. Respiration effects were assessed by the shift of the motion curve during in- and expiration phases.

RESULTS

The PVs showed a mean interpair displacement of 4.1 +/- 0.2 mm and a shift of 5.0 +/- 0.5 mm. Proximal CS references for all LA structures (4.0 +/- 1.1 mm) were superior to the static reference (4.9 +/- 0.7 mm; P = .01). In addition, the shift due to respiration was less pronounced at 3.5 +/- 0.8 mm versus 4.9 +/- 0.5 mm (P = .004), respectively. Motion of extracardiac vessels was influenced by a mean shift of 6.8 +/- 1 mm. The remote subclavian and brachiocephalic veins were more affected (7.6 +/- 0.7 mm) than the pulmonary arteries (5.9 +/- 0.4 mm; P = .002). For the CTI, a minimized mean displacement of less than 4.6 +/- 2.0 mm relative to the proximal CS, RAA, and azygos vein was found.

CONCLUSION

Respiration is the major source of relative motion, which increases with distance from the heart. For LA procedures, a proximal CS reference position is superior to a static reference position.

Elimination of Fluoroscopy Use in a Pediatric Electrophysiology Laboratory Utilizing Three-Dimensional Mapping

OBJECTIVES

The aim of this study was to quantify fluoroscopy use in catheter ablation procedures using a three-dimensional mapping system as the primary source of catheter guidance.

BACKGROUND

Three-dimensional mapping allows continuous visualization of the location of mapping and ablation catheter electrodes. It has been shown to decrease fluoroscopy times. However, the extent to which it can decrease fluoroscopy time has not been completely defined.

METHODS

Thirty patients (mean age 12.9 years; range 4-27 years) with reentrant supraventricular tachycardia underwent catheter ablation using standard protocols. Mapping was performed using the EnSite system (St. Jude Medical, St Paul, MN, USA) in the NavX mode (NavX). Eighteen patients had AVNRT, 12 had AVRT. Fluoroscopy times were compared to an age-matched and rhythm-matched control population.

RESULTS

Procedural success was achieved in 30 of 30 patients (100%). Mean procedure time was 3.27 hours (range 1.83-5.8 hours). Mean fluoroscopy time was 1.05 minutes (range 0-14.8 minutes). Twenty-four of 30 (80%) received no fluoroscopy. Mean fluoroscopy time for the control group was 21.37 minutes (range 5.13-77.13 minutes). Thus fluoroscopy time was 95% less in the study group compared to control (1.05 +/- 2.96 vs 21.37 +/- 18.35 minutes, P < 0.001).

CONCLUSIONS

NavX was used to effectively guide catheters during ablation procedures resulting in a significant decrease in fluoroscopy use. In 80% of the procedures, no fluoroscopy was used. Further advances in the technology may permit additional decreases in x-ray exposure for the 20% of patients who required it.

Nonfluoroscopic Catheter Navigation for Radiofrequency Catheter Ablation of Supraventricular Tachycardia in Children

BACKGROUND

Radiofrequency catheter ablation (RCA) of supraventricular tachycardia (SVT) in children is highly successful but requires exposure to radiation. Nonfluoroscopic mapping systems may significantly reduce fluoroscopy time.

METHODS

Forty consecutive pediatric patients who underwent RCA for accessory pathways (AP) or AV nodal reentrant tachycardia (AVNRT) with use of a nonfluoroscopic navigation system (Ensite NavX) (group A) were compared retrospectively to 40 consecutive patients with similar diagnoses who underwent RCA with fluoroscopic guidance only (group B).

RESULTS

Group A (mean age 12.1+/-2.9 years, mean weight 47+/-13.9 kg) consisted of 11 patients (27.7%) with AVNRT and 29 (72.5%) with AP. Group B (mean age 10.9+/-3.1 years, mean weight 47.1+/-17.1 kg) consisted of 7 patients (17.5%) with AVNRT and 33 (82.5%) with AP. There were no significant differences in AP location, patients with congenital heart disease, and number of radiofrequency lesions. Fluoroscopy time was significantly shorter in group A than in group B (10.4+/-6.1, range 3.1-28.8 minutes, vs 24.9+/-16.0, range 4.4-82.0 minutes, P<0.0001). Procedure duration was also significantly shorter in group A than in group B (170+/-68.5, range 90-420 minutes, vs 218+/-69.3, range 90-360 minutes, P<0.0001). Initial success was 95% in group A and 100% in group B. Tachycardia recurrences occurred in two patients in group A (5%) and six patients in group B (15%). Final success, including repeat ablations for recurrences or failures, was 100% in both groups.

CONCLUSIONS

The use of a nonfluoroscopic system for catheter navigation significantly reduced fluoroscopy exposure and total procedure duration of RCA of common SVT substrates in children.

Electrical isolation of pulmonary veins in patients with atrial fibrillation: reduction of fluoroscopy exposure and procedure duration by the use of a non-fluoroscopic navigation system (NavX®)

AIMS

The aim of the study was to investigate the feasibility of performing segmental pulmonary vein (PV) isolation guided by the NavX (Endocardial Solutions, St Jude Medical, Inc., St Paul, MN, USA) system without the three-dimensional (3D) geometric reconstruction option and whether the use of NavX system will reduce the radiation exposure and procedure duration.

METHODS AND RESULTS

The study included 64 patients with symptomatic paroxysmal or permanent atrial fibrillation, in whom PV isolation was performed using fluoroscopic guidance (n=32) or the NavX system (n=32). Pulmonary vein mapping with a circular mapping catheter allowed the identification and localization of myocardial connections between the PV and the left atrium. PV isolation was performed by radiofrequency ablation of these connections at the atrial aspect of the PV ostium. Primary success rate for isolated PVs did not differ significantly in patients ablated under fluoroscopic guidance vs. those ablated under guidance of NavX system [100/107 PVs (93.5%) vs. 120/124 PV (96.8%; P=n.s.)]. Compared with fluoroscopy guided procedures, NavX-guided procedures showed a significant reduction in the fluoroscopy time (75.8+/-24.5 vs. 38.9+/-19.3 min, P<0.05), total X-ray exposure (93.2+/-51.6 vs. 56.6+/-37.9 Gy cm(2), P=0.03), and total procedural time (237.7+/-65.4 vs. 188.6+/-62.7 min, P=0.01). The mean follow-up was 9.5+/-3.0 months. One patient in each group was lost to follow-up. Seven-day Holter monitoring showed that 23 of 31 patients (74.2%) in the NavX-guided group and 21 of 31 patients (67.7%) in the fluoroscopy-guided group were in sinus rhythm (P=0.57).

CONCLUSION

The 3D visualization of the catheters by NavX system allows a rapid and precise visualization of the mapping and ablation catheters at the PV ostia and markedly reduces fluoroscopy time, total X-ray exposure, and procedural duration during PV isolation compared with ablation performed under fluoroscopy guidance.