3D Electroanatomic Mapping System Research Articles

The long-term outcome of pulmonary vein isolation in paroxysmal atrial fibrillation is significantly influenced by diabetes mellitus in general as well as by an antidiabetic therapy

Abstract Introduction Over the last decades pulmonary vein isolation became a cornerstone in the interventional treatment of paroxysmal atrial fibrillation. Postprocedural recurrences of atrial fibrillation are present in patients with and without concomitant cardiovascular diseases. Purpose The aim of this study was to assess the influence of diabetes mellitus and an antidiabetic therapy on the long-term outcome, defined as freedom of atrial fibrillation, of pulmonary vein isolation in patients with paroxysmal atrial fibrillation Methods All patients underwent pulmonary vein isolation using the combination of a radiofrequency ablation catheter, a pulmonary mapping catheter and a 3D electroanatomic mapping system. Every procedure was carried out according to current clinical and scientific standards. Procedural, clinical and follow-up data were stored for later statistical analysis. All patients received 4 follow-ups in total. In the first 12 postprocedural months patients were followed up after 3, 6 and 12 months. Furthermore, there was one long-term follow-up up to 6 years after the procedure. Results A total of n=1282 patients were included in the study. 39.2% of the patients were female and 60,8% were male. At the timepoint of the procedure the mean age was 63.7 years. The mean follow-up time was 2.2 years. For n=1144 of the included patients the presence respectively the absence of diabetes mellitus was documented. 8.0% (n=92) of these patients had the diagnosis of diabetes mellitus, from which 73.9% (n=68) were and 26.1% (n=24) were not under an antidiabetic therapy. Regarding the long-term outcome, patients without diabetes mellitus had significantly better results (log rank p=0.039). The according Kaplan-Meier-Analysis is shown in figure 1. Patients with diabetes mellitus were significantly older (69.5 years) when compared to patients without diabetes mellitus (63.1 years). However, when data was adjusted for age and gender, diabetes mellitus was still an independent, significant predictor of the recurrence of atrial fibrillation after pulmonary vein isolation. In addition, diabetics under an antidiabetic therapy had a significantly better long-term outcome than the untreated ones (log rank p=0.011). Figure 2 shows the according Kaplan-Meier-Analysis. Conclusion Diabetes mellitus has a significant influence on the long-term outcome of pulmonary vein isolation in patients with atrial fibrillation (log rank p=0.039). Patients without diabetes mellitus showed significantly better outcomes when compared to patients with diabetes mellitus also when adjusting the data for age and gender. Furthermore, the presence of an antidiabetic therapy in diabetics influences the long-term outcomes significantly (log rank p=0.011).

Digital health in the EP lab: routine implementation of remote access and technical support for complex ablation procedures

Abstract Background Complex electrophysiological procedures are performed using three-dimensional (3D) electroanatomical mapping (EAM) systems, which are usually operated on site, by field technical engineers (FTE). Due to a lack of skilled personnel, the engineers usually must travel between different hospitals and the procedures have to be planed in advance. Remote access (RA) technologies were recently implemented in clinical practice, aiming to increase the flexibility in the EP lab and maximise healthcare resources use. Methods Electroanatomical mapping was performed remotely by means of an integrated audio-visual solution for RA. The operator and the FTE communicated exclusively using the RA system, while the latter worked only in home office. Consecutive procedures were prospectively enrolled and analysed in terms of indication, procedural characteristics, feasibility and saved travelled time by the FTA. Results Between September 2022 and July 2023, a total of 133 EP procedures were performed in a high volume, tertiary electrophysiological centre in Germany. The mean age was 67 (57.5, 75.5) years. Women represented 39.8% of the population. The median BMI was 26.2 (23.1, 30.3) Kg/m2. A total of 56 (42.1%) patients underwent an atrial fibrillation ablation procedure (37.5% paroxysmal), 22 (16.5%) an atrial tachycardia ablation, 13 (9.8%) cavotricuspid isthmus ablation, 15 (11.3%) supraventricular tachycardia ablation, 14 (10.5%) a premature ventricular contraction ablation, 12 (9%) ventricular tachycardia ablations and 1 patient an electrophysiological diagnostic study. The median time length of procedure was 130 (96.5, 168) minutes. The median number of radiofrequency applications was 63.5 (22.3, 109.5), while the median RF time was 14.2 (6.9, 25.1) minutes. The fluoroscopy time was 9.2 (6.5, 12.6) minutes, with a median radiation dose of 408.5 (233.0, 631.8) cGy x cm2. The median amount of contrast media was 40 (8.75, 50.0) ml and the median amount of heparin administered was 12000 (8000, 16000) UI. Protamine was used in 9 cases, with a median of 7000 (5000, 7000) UI. Except for one supraventricular procedure, where no arrhythmia induction was possible, all procedures were successful. One major complication was observed. In one case, the internet-based headphone connection was not stable. Therefore, the communication was established via a conventional smartphone. No change to on-site support was needed. The travel time reduction was available in 130 cases. In total, 290 travel hours could be saved. Conclusion The routine implementation of RA for complex EP procedures proved to be safe and efficient. This approach has the potential to increase the feasibility in case of emergency procedures, reduce travel times for FTE and streamline healthcare resources allocation.

Pulsed-field ablation for atrial fibrillation without the use of fluoroscopy.

Pulsed-field ablation (PFA) and fluoroless ablation (FA) are emerging techniques in contemporary in electrophysiology. With widespread use of 3D electroanatomic mapping systems and advanced intracardiac echo (ICE) imaging, fluoroless ablation has become more widely adopted. However, with the importance of tissue contact for lesion durability, initial PFA has been used with fluoroscopic guidance, but both ICE and electroanatomic mapping make fluoroless PFA feasible. The objective of this study is to demonstrate that PFA can be done safely and effectively without fluoroscopy. At a single center, consecutive patients undergoing ablation with a pentaspline PFA catheter using a fluoroless approach are described. The standard 3D anatomic map settings were adjusted with changes in interior and exterior projection, respiratory compensation, and interpolation. In addition, projection map lesions were used to confirm adequate circumferential ablation lesions. ICE was used extensively for wire guidance and evaluation of contact with tissue. Beginning on March 15, 2024, 50 consecutive subjects (19 female/31 male) aged 68.0 (± 13.7) underwent PFA ablation. The average CHA2DS2-VA2Sc score was 3.0 (± 1.9). The average LVEF was 57.3% (± 10.0) and the average LA size was 3.9cm (± 1.2). Projection lesions were placed with every application of PFA. An average of 41.7 (± 8.5) PFA applications were placed. In 100% (50/50) of subjects, acute isolation of the pulmonary veins was achieved. Eighteen subjects also underwent concomitant posterior wall isolation and in 100% of these subjects, posterior isolation was achieved. There were zero complications in this cohort. In 50/50 subjects (100%), fluoroscopy was not used. In comparison to the control cohort, the LA dwell time of the ablation catheter was similar (p = 0.34). In comparison to the traditional PFA with fluoroscopy, this proof-of-concept study shows fluoroless PFA ablation can be performed safely and with similar acute success rates as with use of fluoroscopy.

Cardioneural ablation-the first case series without the use of fluoroscopy.

Cardioneural ablation (CNA) and fluoroless ablation (FA) are emerging procedures and movements in contemporary in electrophysiology. Ablation of ganglionated plexus (GP) inputs in the atrium has been successfully targeted as a treatment for symptomatic bradyarrhythmias due to increased parasympathetic tone. As most of these patients are young, avoidance of ionizing radiation is of critical importance to limit potential long term deleterious effects. With widespread use of 3D electroanatomic mapping systems and advanced intracardiac echo (ICE) imaging, fluoroless ablation has become more widely adopted. However, fluoroless CNA has not been widely performed. The objective of this study is to demonstrate that CNA can be done safely and effectively without fluoroscopy. At a single-center, consecutive patients undergoing CNA with a fluoroless approach are described. GP mapping and ablation were performed in both atria. From the right atrium (RA), the right atrium-superior vena cava (RA-SVC GP), the posteromedial ganglionated plexus (PMLGP), which can be accessed from the right atrium-coronary sinus ostium, and the Vein of Marshall GP (VOM-GP) were evaluated. From the left atrium (LA), the superior left atrial ganglionated plexus (LSGP), the left inferior ganglionated plexus (LIGP), the right anterior ganglionated plexus (RAGP), and the right inferior ganglionated plexus (RIGP) were targeted. Over the study period, beginning on January 31, 2021, 30 consecutive subjects (15 females/15 males) aged 42.9 ± 13.6years underwent GP ablation. The average subject had 9.5 (± 9.2) episodes of syncope prior to ablation. The average CHADS2-VA2SC score was zero. The average LVEF was 64.8% (± 4.9). Two of the subjects had concomitant ablations, six failed prior medical therapy, and one had a prior pacemaker placed. All of the procedures were done without fluoroscopy. The average follow-up was 604 (± 366) days. There were 8 patients that did not improve symptomatically postfirst ablation. Four of the eight underwent repeat ablation and have subsequently improved. 26/30 patients symptomatically improved after the 1st or 2nd ablation. There were no complications noted. In comparison to the traditional CNA with fluoroscopy, this proof of concept study reveals fluoroless GP ablation can be performed safely. In addition, the durability and success rate are comparable to other studies of CNA. Given the young age of the cohort and the longitudinal risks of ionizing radiation, fluoroless CNA is a feasible procedure for this patient population.

Left atrial remodeling and voltage-guided ablation outcome in persistent atrial fibrillation patients according to CHA2DS2-VASc score

BackgroundCHA2DS2-VASc score-related differences have been reported in atrial fibrotic remodeling and prognosis of atrial fibrillation (AF) patients after ablation. There are currently no data on the efficacy of low voltage zone (LVZ)-guided ablation in persistent AF patients according to CHA2DS2-VASc score. We assessed in a cohort of persistent AF patients the extent of LVZ, the regional distribution of LA voltage and the outcome of LA voltage-guided substrate ablation in addition to PVI according to CHA2DS2-VASc score.Methods138 consecutive persistent AF patients undergoing a first voltage-guided catheter ablation were enrolled. 58 patients with CHAD2DS2-VASc score ≥ 3 and 80 patients with CHAD2DS2-VASc score ≤ 2 were included. LA voltage maps were obtained using 3D-electroanatomical mapping system in sinus rhythm. LVZ was defined as < 0.5 mV.ResultsIn the high CHAD2DS2-VASc score group, LA voltage was lower (1.5 [1.1–2.5] vs. 2.3 [1.5–2.8] mV, p = 0.02) and LVZs were more frequently identified (40% vs. 18%), p < 0.01). Female with CHA2DS2-VASc score ≥ 3 (p = 0.031), LA indexed volume (p = 0.009) and P-wave duration ≥ 150 ms (p = 0.001) were predictors of LVZ. After a 36-month follow-up, atrial arrhythmia-free survival was similar between the two groups (logrank test, P = 0.676).ConclusionsAF patients with CHAD2DS2-VASc score ≥ 3 display more LA substrate remodeling with lower voltage and more LVZs compared with those with CHAD2DS2-VASc score ≤ 2. Despite this atrial remodeling, they had similar and favorable 36 months results after one single procedure. Unlike male with CHAD2DS2-VASc score ≥ 3, female with CHAD2DS2-VASc score ≥ 3 was predictor of LVZ occurrence.

Characterization of patients with extensive left atrial myopathy referred for atrial fibrillation ablation: incidence, predictors, and outcomes.

Although atrial fibrosis has a relevant impact on ablation success rate, experimental studies have reported that extensive fibrosis may be accompanied by a reduced burden secondary to a prominent depression of atrial excitability. We aimed to identify clinical and echocardiographic factors associated with extensive left atrial myopathy (ELAM), to analyze the predictive ability of established scores (AF score, APPLE, and DR-FLASH) and assess outcomes in terms of AF recurrence, left atrial flutter, and post-procedural heart failure admissions. A total of 950 consecutive patients undergoing the first AF ablation were included. A 3D electroanatomical mapping system (CARTO3, Biosense Webster) was created using a multipolar mapping catheter (PentaRay, Biosense Webster). ELAM was defined as ≥ 50% low voltage area. A subanalysis with four groups was also created (< 10%; 10-20%; 10-20%; and > 30%). Logistic regressions, Cox proportional hazards models, and log-rank test were used to test the predictors independently associated with the presence of ELAM and AF recurrence. The model was prospectively validated in a cohort of 150 patients obtaining an excellent ability for prediction AUC 0.90 (CI 95% 0.84-0.96). Overall, 78 (8.42%) presented ELAM. Age, female sex, persistent AF, first-degree AV block, and E/e' were significant predictors. The model incorporating these factors outperformed the existing scores (AUC = 0.87). During a mean follow-up of 20months (IQR 9 to 36), patients with ELAM presented a higher rate of AF recurrence (42.02% vs 26.01%, p = 0.030), left atrial flutter (26.03% vs 8.02%, p < 0.001), and post-procedural heart failure admissions (12.01% vs 0.61%, p < 0.001) than non-ELAM patients. This study reveals the incidence and clinical factors associated with ELAM in AF, highlighting age, female, persistent AF, first-degree AV block, and E/e'. Importantly, the presence of ELAM is associated with poorer outcomes in terms of recurrence and HF admission.

Intracardiac Echocardiography: An Invaluable Tool in Electrophysiological Interventions for Atrial Fibrillation and Supraventricular Tachycardia.

Researchers have investigated ways to develop optimal imaging techniques to increase the safety and effectiveness of electrophysiological (EP) procedures. Intracardiac echocardiography (ICE) is an advanced imaging tool that can directly visualize cardiac anatomical structures in high resolution, assess tissue heterogeneity and arrhythmogenic substrates, locate intracardiac catheters, monitor catheter-tissue contact and ablation injury in real-time, excluding intracardiac thrombi, and quickly detect procedural complications. Additionally, real-time imaging via ICE can be integrated with a three-dimensional (3D) electroanatomical mapping (EAM) system to reconstruct cardiac anatomy. This technique also promotes the development of zero-radiation EP procedures. Many EP studies and procedures have implemented ICE because it has several advantages over fluoroscopy and transesophageal echocardiography (TEE). ICE-guided EP procedures can be performed under conscious sedation; esophageal intubation and additional anesthesiologists are not required. Atrial fibrillation (AF) and supraventricular tachycardias (SVT) are the most common tachyarrhythmias in clinical settings. A comprehensive understanding of critical anatomical structures, such as the atrial septum, fossa ovalis (FO), and great heart vessels, is needed for the successful catheter ablation of these arrhythmias.

Stereotactic arrhythmia radioablation for refractory ventricular tachycardia. A retrospective analysis and optimisation of the planning phase

Abstract Introduction Stereotactic arrhythmia radioablation (STAR) is used as a rescue treatment for refractory ventricular tachycardia (VT). However, the planning phase to accurately delineate the clinical target volume (CTV) still suffers from limitations due to the incompatibility of data formats between 3D electro-anatomical mapping systems (EAM) used for VT ablation and STAR planning software. The concordance between the CTVs as defined by the planning software (CTVSTAR) and the CTV based on EAM data (CTVEAM) remains unknown. Purpose Within the STOPSTORM European consortium, we compared the concordance between CTVSTAR and CTVEAM in our series of 13 patients (pts) treated by STAR for refractory VT. We also evaluated need for redo ablation of VT after STAR. Method Using the software Slicer3D, two protocols were retrospectively compared: Protocol 1 comprised the manual contouring of the CTVSTAR based on 4D-CT SCAN drawn side-by-side using EAM (Carto3, Biosense Webster) screenshots and diagnostic reports. Protocol 2 comprised semiautomatic segmentation of CTVEAM based on 4D-CT SCAN using imported EAMs annotated with landmarks for VT substrate delimitation. The delineation of CTVEAM included 3 steps: (1) semiautomatic segmentation of ventricular myocardium (VM), the blood-pool of the concerned ventricle and at least 2 additional cardiac cavities; (2) 3D-alignment of EAM with the segmented cavities; and (3), 3D-delineation of CTVSTAR identified as the transmural section of VM segment surrounding the EAM’s VT substrate delimited by STAR tags (Figure 1). Volume overlap (Dice coefficient, 100% meaning complete overlap) and volume absolute difference (VAD, 0% meaning similar volumes) between CTVs were compared. The following cumulative averages were computed over time: redo ablation (RedoA) and CTV. Results Figure 1 illustrates the last treated patient (#13) in whom the delineated volumes, CTVSTAR (red) and CTVEAM (blue), displayed good matching (Dice 72% and VAD 4. Figure 2 shows the comparison between CTVSTAR and CTVEAM for the 13 pts (65±7 yo) treated with STAR, resulting in a mean Dice of 47±17% and mean VAD of 40±51%. Figure 3 shows the cumulative RedoA and the cumulative averaged CTVSTAR and CTVEAM over time. Interestingly, the need for redo ablation decreased with increasing CTVs. Conclusion Our study demonstrates the efficacy of STAR treatment for refractory VT. Our confidence in STAR led to higher CTVs and lower RedoA over time. The high variability of CTV delineation using two different protocols suggests that STAR planning phase can be optimised by appointing intraprocedural anatomical landmarks to the VT substrate.

Termination without global capture: electrocardiographic and anatomical characteristics using 3D-electroanatomical mapping system in reentrant ventricular tachycardia

Abstract Background Termination without global capture (TWGC) is the phenomenon which a pacing stimulus applied during ventricular tachycardia (VT) terminates the tachycardia without generating a QRS complex, and is considered as an indicator for the critical component of the circuit. The details of the electrocardiographic and anatomical characteristics of the site using a 3D-electroanatomical mapping system (3D-EAM) remain unknown. Purpose This study aimed to retrospectively analyze the cases that showed TWGC during VT mapping and ablation, and to investigate the electrocardiographic characteristics and relationship with the substrate identified by 3D-EAM. Methods Of 632 cases of VT associated with structural heart disease from July, 2019 to July, 2023 at a university hospital and a university medical center, cases with TWGC were analyzed. Results TWGC was observed in 10 patients (median age 61 years, 9 males, 5 ischemic cardiomyopathy, median LVEF 31%) at least once (12 times) in 11 locations. Local capture was observed in 6. The QRS morphology generated by continued pacing after TWGC matched the clinical VT in only 5 VTs (42%). Five showed decremental conduction of stimulus to QRS interval following the TWGC. In 11 locations, 4 corresponded to scar area (&amp;lt;0.1 mV) in the voltage map, 6 to border zone (0.1-1.5 mV), and 1 had no information on 3D-EAM. Of 12 times of TWGC, 3 were at the entrance, 1 at the central isthmus, and 1 at the exit. Acute elimination of clinical VT was successful in 7 of 10. Conclusions More than half of the sites with TWGC were located at the border zone in 3D-EAM. TWGC also occurred in the central or exit area, and local capture was observed frequently.Termination without global capture

Feasibility and safety of cavotricuspid isthmus ablation using exclusive intracardiac echocardiography guidance: a proof-of-concept, observational trial

Abstract Introduction Catheter ablation is the preferred treatment for typical atrial flutter (AFl), although it can pose challenges due to anatomical abnormalities. The integration of 3D electroanatomical mapping systems (EAMS) has notably diminished the need for fluoroscopy in AFl ablation procedures. Intracardiac echocardiography (ICE) has also demonstrated advantages in reducing radiation exposure during AFl ablation. Nevertheless, there is a lack of evidence on the feasibility of ICE-guided, zero-fluoroscopy AFl ablation without the use of EAMS. Methods In this prospective study, we enrolled 80 patients with CTI-dependent AFl. The initial 40 patients underwent ablation guided by standard fluoroscopy along with ICE (Standard ICE group), whereas the remaining 40 patients underwent zero-fluoroscopy ablation exclusively using ICE (Zero ICE group). Procedure outcomes, including acute success, procedural duration, fluoroscopy duration, radiation dose, and any associated complications, were compared between the groups. Results Both groups achieved a 100% acute success rate. In the Zero ICE group, the zero-fluoroscopy approach was successfully executed in 39 out of 40 cases (97.5%). There were no significant differences in procedure time (55.5 (46.5; 66.8) min vs. 51.5 (44.0; 65.5), p=0.50) and puncture to first ablation time (18 (13.5; 23) min vs. 19 (15; 23.5) min, p=0.50) between the groups. The Zero ICE group had significantly lower fluoroscopy time (57 (36.3; 90) sec vs. 0 (0; 0) sec, p&amp;lt;0.001) and dose (3.17 (2.27; 5.63) mGy vs. 0 (0; 0) mGy, p&amp;lt;0.001 compared to the Standard ICE group. Total ablation time was longer in the Standard ICE group (597 (447; 908) sec vs. 430 (260; 750), p=0.02), but total ablation energy (22458 (14836; 31116) Ws vs. 17043 (10533; 29302) Ws, p=0.10) did not differ significantly. First-pass bidirectional conduction block of the CTI and acute reconnection rates were comparable between the groups. No complications or recurrences were noted during the follow-up period. Conclusion ICE-guided, zero-fluoroscopy CTI ablation for AFl using only ICE is feasible and safe. This method effectively eliminates radiation exposure without compromising procedural duration, total ablation time, or acute success rates.isthmus ablation by ICE

Real-world multicenter registry on a novel focal lattice tip catheter toggling between pulsed electric field and radiofrequency for atrial tachyarrhythmia ablation

Abstract Background Pulsed field ablation (PFA) has emerged as a novel non-thermal energy source for cardiac tissue ablation. A novel focal 9mm lattice tip catheter, namely Sphere-9 (Affera Inc), has recently received regulatory approval; the technology is part of a technology that allows the delivery of either pulsed electric field or radiofrequency energy and incorporates a proprietary 3D electroanatomical mapping system. Purpose To describe the first real-world, multicenter experience with the AfferaTM system. Methods Consecutive AF patients undergoing first-time or redo atrial tachyarrhythmia ablation with the AfferaTM system in two different centres between August and November 2023 were prospectively enrolled. PFA was always used to ablate the posterior left atrium, whereas anterior applications were performed using either radiofrequency energy (RF/PF strategy) or PFA (PF/PF strategy) based on operator's discretion. Data on first-pass pulmonary vein isolation (PVI) and posterior wall isolation (PWI), as well as success rate of extrapulmonary ablation were reported. Primary safety endpoint included any technology-related periprocedural complications. Results 46 patients (mean age: 67±10; 41.3% males, 60.8% non-paroxysmal AF) were included. 5 (10.8%) patients were in atrial flutter (AFlu) at the beginning of the procedure, whereas AF was the rhythm at presentation in 19 (41.3%) others. First-time PVI was performed in 37 (80.4%) patients, 68.4% of whom received concomitant PWI. PVI was performed with PFA-only in 27% of them. First-pass isolation was achieved in 97.3% and 100% of PVI and PWI cases, respectively. Additional lesions included an anterior or posterior mitral line (6 and 15 patients), CTI (4 patients) or substrate ablation in 3 patients. Evidence of first-pass line block was documented in 96.4% of patients. The remaining 9 (19.6%) patients had already undergone a previous ablation; remapping showed 27.7% of PVs requiring reisolation. PWI was performed in 88.9% of them, for the first time (75%) or due to reconnection (25%). Additional lesions included an anterior or posterior mitral line (3 and 3 patients) or CTI in 2 patients. Evidence of first-pass line block was documented in 100% of patients. In 3 AFlu patients, the arrhythmia was mapped and termination was achieved while performing an AML (2 patients) and CTI (1 patient). Procedural duration was 96.5±15.6 min for first time and 97.8±12.6 min for redo procedures. Mean left atrial dwelling and fluoroscopy times were 75.4±17.6 min and 7.36±2.1 min, respectively. No technology-related complications were documented. Conclusions AF ablation with the focal 9-mm lattice tip catheter Sphere-9 confirmed high efficacy and safety in a real-world population.

Left ventricular wall thickening predicts left atrial low voltage areas in patients undergoing catheter ablation for atrial fibrillation

Abstract Background The success rate of circumferential pulmonary vein isolation (CPVI) remains suboptimal in patients with paroxysmal and persistent atrial fibrillation; moreover, the detection of low voltage areas (LVA) in the left atrium does predict an even higher recurrence rate of atrial tachyarrhythmias after the procedure. Left ventricular wall thickening (LVWT) is known to correlate with left atrial volume; however, no data is available whether LVWT is predictive of the presence of left atrial LVA. Purpose The aim of this study was to investigate whether LVWT is predictive of left atrial LVA and to verify that the presence of LVA confer a higher arrhythmia recurrence rate after catheter ablation for atrial fibrillation. Methods A total of 374 patients who undervent CPVI with the use of 3D electroanatomical mapping system as a primary procedure were enrolled in the study. Transthoracic echocardiography was performed in all patients prior the procedure with measurement of the thickness of the septum and the posterior wall. Patients were classified based on LVWT as normal (females:≤9mm, males:≤10mm), borderline (females:10-11mm, males: 11-12mm) and increased (females:≥12mm, males:≥13mm). A detailed left atrial voltage map was obtained in all patients prior to ablation with the identification of LVA (bipolar voltage &amp;lt;0.5mV with an area &amp;gt;5cm2). Arrhythmia recurrence was defined as documented atrial fibrillation or atrial tachycardia lasting for at least 30 seconds. Results Among 374 patients (mean age: 59.0±10.2 years, 131 females) 94, 195 and 85 were considered to be normal, borderline and increased based on LVWT, respectively. LVA were found in 29.9% (112/374) of patients. According to LVWT, LVA were detected in 16.0% (15/94), 31.3% (61/195) and 42.4% (36/85) in patients with normal, borderline and increased wall thickness, respectively, p=0.005. Patients with left atrial LVA had a higher [60.7% (68/112)] arrhythmia recurrence compared to those without low voltage areas [35.1% (92/262)] during a mean follow-up of 2.1±1.9 years, p&amp;lt;0.0001. Conclusions Left ventricular wall thickening predicts the presence of left atrial low voltage areas in patients undergoing catheter ablation for atrial fibrillation. Low voltage areas confer a higher arrhyhtmia recurrence rate during follow-up.

Use of three-dimensional electroanatomic mapping for epicardial access: needle tracking, electrographic characteristics, and clinical application.

Pericardiocentesis is usually completed under fluoroscopy. The electroanatomic mapping (EAM) system allows visualizing puncture needle tip (NT) while displaying the electrogram recorded from NT, making it possible to obtain epicardial access (EA) independent of fluoroscopy. This study was designed to establish and validate a technique by which EA is obtained under guidance of three-dimensional (3D) EAM combined with NT electrogram. 3D shell of the heart was generated, and the NT was made trackable in the EAM system. Unipolar NT electrogram was continuously monitored. Penetration into pericardial sac was determined by an increase in NT potential amplitude and an injury current. A long guidewire of which the tip was also visible in the EAM system was advanced to confirm EA. Epicardial access was successfully obtained without complication in 13 pigs and 22 patients. In the animals, NT potential amplitude was 3.2 ± 1.0 mV when it was located in mediastinum, 5.2 ± 1.6 mV when in contact with fibrous pericardium, and 9.8 ± 2.8 mV after penetrating into pericardial sac (all P ≤ 0.001). In human subjects, it measured 1.54 ± 0.40 mV, 3.61 ± 1.08 mV, and 7.15 ± 2.88 mV, respectively (all P < 0.001). Fluoroscopy time decreased in every 4-5 cases (64 ± 15, 23 ± 17, and 0 s for animals 1-4, 5-8, 9-13, respectively, P = 0.01; 44 ± 23, 31 ± 18, 4±7 s for patients 1-7, 8-14, 15-22, respectively, P < 0.001). In five pigs and seven patients, EA was obtained without X-ray exposure. By tracking NT in the 3D EAM system and continuously monitoring the NT electrogram, it is feasible and safe to obtain EA with minimum or no fluoroscopic guidance.

The Fluoroless Future in Electrophysiology: A State-of-the-Art Review.

Fluoroscopy has always been the cornerstone imaging method of interventional cardiology procedures. However, radiation exposure is linked to an increased risk of malignancies and multiorgan diseases. The medical team is even more exposed to X-rays, and a higher incidence of malignancies was reported in this professional group. In the last years, X-ray exposure has increased rapidly, involving, above all, the medical team and young patients and forcing alternative fluoroless imaging methods. In cardiac electrophysiology (EP) and pacing, the advent of 3D electroanatomic mapping systems with dedicated catheters has allowed real-time, high-density reconstruction of both heart anatomy and electrical activity, significantly reducing the use of fluoroscopy. In addition, the diffusion of intracardiac echocardiography has provided high anatomical resolution of moving cardiac structures, providing intraprocedural guidance for more complex catheter ablation procedures. These methods have largely demonstrated safety and effectiveness, allowing for a dramatic reduction in X-ray delivery in most arrhythmias' ablations. However, some technical concerns, as well as higher costs, currently do not allow their spread out in EP labs and limit their use to only procedures that are considered highly complex and time-consuming and in young patients. In this review, we aim to update the current employment of fluoroless imaging in different EP procedures, focusing on its strengths and weaknesses.

Catheter ablation of supraventricular tachycardia and atrial flutter with no or minimal use of fluoroscopy: the initial experience of a single Bulgarian center

Introduction: Catheter ablation (CA) is an established therapy for most arrhythmias. Non-&amp;#64258; uoroscopic three-dimensional (3D) electroanatomic mapping systems allow ablation of supraventricular tachycardia (SVT) and atrial &amp;#64258; utter (AFL) with zero or near-zero &amp;#64258; uoroscopy (ZF/NZF). The current study aims to report our initial experience with ZF/NZF in SVT or AFL CA. Material and methods: We conducted a single-center prospective registry enrolling consecutive patients referred for CA of SVT or AFL. ZF/NZF CA was attempted in all patients using a commercially available 3D mapping&amp;nbsp;system. Fluoroscopy use was allowed at any point of the procedure. Procedural characteristics and long-term outcome were analyzed. The learning curve effect was also studied. Results: Sixty-three patients (age 53.5 &amp;plusmn; 14.1, 57% males) with SVT or AFL were enrolled. According to arrhythmia type typical AVNRT was diagnosed in 36 (57.1%) cases, right atrial &amp;#64258; utter in 25 (39.7%) cases, left-sided accessory pathway in 1 (1.6%) and focal right atrial tachycardia in 1 (1.6%) case. Three patients (4.8%) had two arrhythmia substrates. The procedure was performed with ZF in 49/63 cases (77.8%), while NZF was necessary in 14 (22.2%) patients with a &amp;#64258; uoroscopy time of 220 &amp;plusmn; 169 sec and a dose-area product of 7556 &amp;plusmn; 5886 mGy*cm2. Median procedural time was 88 (IQR 25-75 percentile 71.5-116) min with 22 (IQR 25-75 percentile 16-31) min of mapping time. Acute procedural success was accomplished in all patients with no periprocedural complications. Over a follow-up of 12 &amp;plusmn; 3 months, all patients remained arrhythmia-free. There was a learning curve effect with a signi&amp;#64257; cant reduction of procedural time (P = 0.025) and a signi&amp;#64257; cant difference (P = 0.019) in the rate of &amp;#64258; uoroscopy use among different periods of the study duration. Conclusion: ZF/NZF CA of SVT and AFL is associated with high ef&amp;#64257; cacy and safety. Entirely &amp;#64258; uoroless CA can be performed in the vast majority of patients. It is a feasible approach associated with a detectable learning curve effect.&amp;nbsp;

Digital health in the EP lab: Initial experience using remote access and technical support for complex ablation procedures

Abstract Aims/Objectives Three-D electroanatomical mapping (EAM) systems are a prerequisite for treatment of complex arrhythmias. Until date, the EAM system is operated by qualified staff or a field technical engineer (FTE) from the control room. Novel technology allows for remote access (RA) of the EAM from anywhere in the world. RA increases the flexibility of the EP lab, reduces travel time for the FTE and overcomes hospital access limitations e. g. during the COVID-19 pandemic. We report on the safety and feasibility of remote operation of the EAM for complex ablation procedures. Methods RA mapping was achieved by combining the EAM software with an integrated audiovisual solution for remote support. Communication between the operator and the remote support was achieved using internet-based headphones in the RA group. The 3D EAM system was controlled exclusively from home office. In the conventional group (CG), EAM was exclusively controlled from the control room in the EP lab. Ablation procedures were performed as per institutional standard. Results We investigated 50 RA assisted consecutive electrophysiological procedures from 09/2022 to 02/2023 in our University Heart Center. We compared a group of patients undergoing ablation procedures with RA assistance (28/50 (56%) patients were male, median age: 66.5 yrs [IQR 56, 76], BMI: 25.2 kg/m2 [IQR 22, 30]) with a control group (31/50 (62%) male, median age: 66.5 yrs [IQR 54, 78], BMI 28.2 kg/m2 [IQR 24, 30], p &amp;gt; 0.05 for all). Ablation procedures were matched in both groups: 20 pulmonary vein isolations (3 paroxysmal, 17 persistent atrial fibrillation ), 4 cavotricuspidal isthmus ablations, 13 ablations of atrial tachycardia, 1 premature ventricular complex ablation, 3 of ventricular tachycardia, 2 AV reentry tachycardia and 7 AV-node reentry tachycardia cases. In the RA group, the 3D EAM system was controlled exclusively from home office in all patients. In one patient, the internet based headphone connection was instable. Therefore, the communication was established via a conventional smartphone. No other technical issue was noted. No switch to in house support was required. There were no major complications observed. Procedural data (total procedure time median 100 min [IQR 76, 120] vs. control group 86 min [IQR 60, 110], total fluoroscopy time (median 9.1 min [IQR 6, 13] vs. control group 8.7 min [IQR 5, 12], p &amp;gt; 0.05) were comparable to previous procedures without RA. Due to RA travel time could be reduced by 139 hr in total in comparison to the control group. Conclusions RA for EAM of any arrhythmia is feasible and safe in this single center study. Procedural data were comparable to previous procedures. In the future, this new solution might have a great impact on facilitating EP procedures.Table procedural data

The zero fluoroscopic approach to avnrt ablation significantly reduces radiation without compromising safety, efficacy or procedure time compared to a conventional or minimal fluoroscopic approach

Abstract Introduction In 2020, we showed that ablation of AVNRT (induced under conventional fluroscopy) with a 3D electro-anatomical mapping system (EAMS) (minimal X-RAY group) significantly reduces radiation exposure without compromising safety, efficacy and procedure time compared to a procedure performed entirely under conventional fluoroscopy (X-RAY group). Purpose The objective of this study was to determine whether the direct use of EAMS in selected patients with a high probability of induction of AVNRT could reduce radiation exposure to near zero without compromising the safety, efficacy and duration of the procedure (EAMS group) Methods We compare the 136 patients in the X-RAY group, the 141 patients in the minimal X-RAY group with 39 patients included in the EAMS group (included between July 2020 and December 2022). All procedures were performed at a single centre in Belgium using the same 3D electroanatomical mapping system. In the EAMS group, fluoroscopy had to be used to guide catheter progression for only 5 patients. We compared radiation dose, acute success, complication rates and procedure duration. Results AVNRT induction was achieved in 38 of 39 patients in the EAMS group. Only one patient was not inducible, but the slow pathway ablation was performed on the basis of the arrythmic ECG recording which was highly suggestive of AVNRT; the success of the ablation could therefore not be validated acutely. Radiation dose in the EAMS group was significantly lower compared to the minimal X-RAY group and X-RAY group (8,5 vs 1179 and 2686 mgray.cm2, p &amp;lt;0,0001) and fluroscopic time was obviously shorter (0,02 vs 2,5 and 8,6 minutes, p&amp;lt;0,0001). Procedural time (74,3 vs 70 and 69 mon, p = NS) and success rate (97,5% vs 99 and 98%, p = NS) were not significantly different in the three groups. No serious complications were observed in any group. No minimal complication were reported in the zero-fluoroscopy group. Conclusion AVRNT catheter ablation using a zero-fluoroscopic approach with EAMS significantly reduces radiation exposure without compromising safety, efficacy or procedure time.

Integration of electro-anatomical maps in the planning phase of stereotactic arrhythmia radioablation for refractory ventricular tachycardia

Abstract Introduction Despite the efficacy of stereotactic arrhythmia radioablation (STAR) for the treatment of refractory ventricular tachycardia (VT), the planning phase to precisely delineate the arrhythmogenic substrate still suffers from limitations due to the incompatibility of data formats between 3D electro-anatomical mapping systems (EAM) and STAR planning software (CyberKnife). Purpose Within the STOPSTORM European consortium, we present a workflow to integrate all 3D EAM data (e.g. voltage, activation time, anatomical tags) into the STAR planning software using the open source software Slicer3D to improve targeting of the arrhythmogenic substrate. Method Two protocols were compared retrospectively. Protocol 1 (STAR gold-standard) comprised the manual contouring of the clinical target volume (CTV) on planning 4D-CAT SCAN drawn side-by-side using EAM (Carto3, Biosense Webster) screen-shots and diagnostic reports. Protocol 2 comprised semiautomatic segmentation of CTV on planning 4D-CAT SCAN using imported EAMs annotated with landmarks for VT target delimitation. The semiautomatic segmentation of CTVs included three steps: (1) semiautomatic segmentation of ventricular myocardium (VM), the blood-pool of the concerned ventricle and at least two additional cardiac cavities; (2) 3D alignment of EAM with the segmented cavities; and (3), 3D delineation of CTV identified as the transmural section of VM segment surrounding the EAM’s VT target delimited by the annotated landmarks. The volume overlap (Dice coefficient) and the absolute difference of the CTVs obtained with the two protocols were compared. Both measurements were expressed in percentage as follows: Dice coefficient 0% means no overlap and 100% complete overlap; absolute difference of volumes 0% means no difference and 100% means that one CTV was twice the size of the CTV generated by the other protocol. Results Both protocols were applied to four patients (65.5 ± 8.5 yo) with refractory VT successfully treated with STAR. Figure 1 shows an example (Patient 1) of the CTV contouring using the CARTO EAMs aligned with the CT images in Slicer3D. Figure 2 illustrates significant mismatch between the segmented CTVs of the two protocols. The median volume overlap of the CTVs was 44%, while the median volume absolute difference was 35%. Table 1 reports detailed results. Conclusion Our study reveals a high variability of CTV delineation for STAR using two different protocols. The intraprocedural assignment of anatomical landmarks for VT target delimitation on EAM appears promising to improve CTV delineation. Further research is needed to evaluate the correlation between STAR outcome and CTV delineation accuracy.

Cardioneuroablation for symptomatic bradyarrhythmia: for whom it fails?

Abstract Background Cardioneuroablation (CNA) has been proposed as a new therapeutic approach in selected patients with symptomatic functional bradyarrhythmia including recurrent neurally-mediated syncope. Purpose In patients after CNA, we investigated the potential predictors of the recurrence of clinically significant bradyarrhythmia. Methods A retrospective study included 187 consecutive patients (age: 40±12 years; 57 % of males; predominant AV nodal phenotype of the disorder in 37 % of patients; post-atropine sinus rate acceleration by 72±31 %) who underwent their first CNA at our centre from 2014 to 2022 and were followed for the minimum of 3 months. Biatrial radiofrequency ablation was performed under general anaesthesia by irrigated-tip catheter at empirical sites of ganglionated plexi (GP) with the navigation by 3D electroanatomic mapping system and intracardiac echocardiography. Anterior right GP and posteromedial left GP were always targeted to modulate the innervation of both sinoatrial and atrioventricular nodes, irrespective of the clinical manifestation of the disease. The loss of responsiveness of both nodes to extracardiac vagus nerve stimulation (frequently bilateral) was the procedural endpoint. The association of baseline, procedural, and early follow-up characteristics with the recurrence of clinically significant bradyarrhythmia was analyzed. Results CNA with the procedural duration of 154±32 min and radiofrequency time of 14±7 min resulted acutely in sinus rate acceleration by 27±13 bpm, shortening of AH interval by 16±28 ms, an increase of Wenckebach point by 26±28 bpm, shortening of AV node effective refractory period by 114±128 ms, and sinus node recovery time by 462±867 ms. At the 3-month visit, the sinus rate was still significantly higher (83±14 bpm) than at baseline (61±13 bpm); with acceleration by 23±14 bpm. During a median follow up of 33 months (IQR: 18-48 months), recurrence of clinically significant bradyarrhythmia was documented in 18 (10 %) patients. Re-CNA was performed in 11 patients and was scheduled in 3 patients. In 6 (3 %) patients, a pacemaker was finally implanted. Compared to the rest of the population, patients with bradyarrhythmia recurrence were non-significantly younger (36±12 vs. 40±12 years, P=0.16) and had non-significantly less acceleration of sinus rate at the 3-month post-CNA visit (by 18±11 vs. 23±13 bpm, P=0.10) suggesting a trend to more pronounced reinnervation of the sinus node. Conclusion Long-term clinical efficacy of CNA is reasonably high. We did not identify practically useful predictors of CNA failure. This investigation was significantly limited by the low rate of clinical events.

Feasibility and safety of cavotricuspid isthmus ablation using exclusive intracardiac echocardiography guidance: a proof-of-concept, observational trial.

Catheter ablation is the preferred treatment for typical atrial flutter (AFl), but it can be challenging due to anatomical abnormalities. The use of 3D electroanatomical mapping systems (EAMS) has reduced fluoroscopy exposure during AFl ablation. Intracardiac echocardiography (ICE) has also shown benefits in reducing radiation exposure during AFl ablation. However, there is a lack of evidence on the feasibility of ICE-guided, zero-fluoroscopy AFl ablation without the use of EAMS. In this prospective study, we enrolled 80 patients with CTI-dependent AFl. The first 40 patients underwent standard fluoroscopy + ICE-guided ablation (Standard ICE group), while the other 40 patients underwent zero-fluoroscopy ablation using only ICE (Zero ICE group). Procedure outcomes, including acute success, procedure time, fluoroscopy time, radiation dose, and complications, were compared between the groups. The acute success rate was 100% in both groups. Out of the 40 cases, the zero-fluoroscopy strategy was successfully implemented in 39 cases (97.5%) in the Zero ICE group. There were no significant differences in procedure time [55.5 (46.5; 66.8) min vs. 51.5 (44.0; 65.5), p = 0.50] and puncture to first ablation time [18 (13.5; 23) min vs. 19 (15; 23.5) min, p = 0.50] between the groups. The Zero ICE group had significantly lower fluoroscopy time [57 (36.3; 90) sec vs. 0 (0; 0) sec, p < 0.001] and dose [3.17 (2.27; 5.63) mGy vs. 0 (0; 0) mGy, p < 0.001] compared to the Standard ICE group. Total ablation time was longer in the Standard ICE group [597 (447; 908) sec vs. 430 (260; 750), p = 0.02], but total ablation energy [22,458 (14,836; 31,116) Ws vs. 17,043 (10,533; 29,302) Ws, p = 0.10] did not differ significantly. First-pass bidirectional conduction block of the CTI and acute reconnection rates were similar between the groups. No complications or recurrences were observed during the follow-up period. Our study suggests that zero-fluoroscopy CTI ablation guided solely by ICE for AFl is feasible and safe. Further investigation is warranted for broader validation.