Electroanatomic Mapping System Research Articles

Unipolar Voltage Mapping to Predict Recovery of Left Ventricular Ejection Fraction in Patients With Recent-Onset Nonischemic Cardiomyopathy.

The ability to predict recovery of left ventricular ejection fraction (LVEF) in response to guideline-directed therapy among patients with nonischemic cardiomyopathy is desired. We sought to determine whether left ventricular endocardial unipolar voltage measured during invasive electroanatomic mapping could be used to predict LVEF recovery among those with recent-onset nonischemic cardiomyopathy. We analyzed the left ventricular voltage maps of patients included in the eMAP trial (Electrogram-Guided Myocardial Advanced Phenotyping; NCT03293381), a prospective, nonrandomized, interventional trial conducted at 2 institutions between 2017 and 2020. Patients had recent-onset nonischemic cardiomyopathy defined by LVEF ≤45% and development of symptoms or signs of heart failure within the past 6 months. Detailed voltage maps of the left ventricular endocardium were generated using the CARTO electroanatomic mapping system. Abnormal unipolar amplitude was defined as <8.27 mV. The primary end point was recovery of LVEF (Recovery) defined by a 1-year LVEF ≥50% or ≥45% with ≥10% increase from baseline. Of the 29 enrolled patients (median age, 49 years [25th percentile, 39; 75th percentile, 59], 8 females [27.6%]), LVEF recovered in 13 (44.8%) by 1-year follow-up. The percentage of total endocardial surface area with unipolar voltage abnormality (AUA) was significantly lower among Recovery patients than No Recovery patients (18.2% [6.4, 22.4] versus 80.0% [29.5, 90.9]; P=0.004). Percent AUA was associated with lower likelihood of Recovery (odds ratio, 0.64 per 10% increase in AUA; 95% CI, 0.47-0.88; P=0.006). A 28% cutoff value for percent AUA was 92% sensitive and 75% specific with an area under the receiver operating characteristic curve of 0.81 (95% CI, 0.63-0.99; P=0.001) for predicting recovery versus no recovery. The majority of patients (12 of 13; 92.3%) with a percent AUA >28% did not recover. Left ventricular unipolar voltage abnormality is a potent predictor of LVEF recovery among patients recently diagnosed with nonischemic cardiomyopathy. Detailed left ventricular unipolar voltage mapping could therefore be used as a valuable prognostic tool in guiding treatment decisions.

Drug therapy and catheter ablation for management of arrhythmias in continuous flow left ventricular assist device's patients. A Clinical Consensus Statement of the European Heart Rhythm Association and the Heart Failure Association of the ESC.

Left ventricular assist devices (LVADs) are an increasingly used strategy for the management of patients with advanced heart failure. Although these devices effectively improve survival, atrial and ventricular arrhythmias are common with a prevalence of 20-50% at one year after LVAD implantation. Arrhythmias predispose these patients to additional risk and are associated with considerable morbidity from recurrent implantable cardioverter-defibrillator (ICD) shocks, progressive failure of the unsupported right ventricle, and herald an increased risk of mortality. Management of patients with arrhythmias and LVAD differs in many aspects from the general population heart failure patients. These include ruling out the reversible causes of arrhythmias that in LVAD patients may include mechanical irritation from the inflow cannula and suction events. For patients with symptomatic arrhythmias refractory to medical treatment, catheter ablation might be relevant. There are specific technical and procedural challenges perceived to be unique to LVAD-related ventricular tachycardia ablation such as vascular and LV access, signal filtering, catheter manoeuvrability within decompressed chambers, and electroanatomic mapping system interference. In some patients, the arrhythmogenic substrate might not be readily accessible by catheter ablation after LVAD implantation. In this regard, the peri-implantation period offers a unique opportunity to surgically address arrhythmogenic substrate and suppress future ventricular tachycardia recurrences. This document aims to address specific aspects of the management of arrhythmias in LVAD patients focusing on anti-arrhythmic drug therapy and ablations.

Procedural outcomes of fluoroscopy-less catheter ablation for atrial fibrillation

Abstract Background Radiofrequency catheter ablation is superior therapy to antiarrhythmic drugs for maintaining sinus rhythm in atrial fibrillation (AF) patients. Traditional fluoroscopy-guided AF ablation poses risks of prolonged radiation exposure for both patients and medical staff. Recent advancements in fluoroscopy-less catheter ablation techniques offer potential solutions, but comprehensive data on their effectiveness and safety are lacking. Purpose To evaluate the procedural outcomes and safety of fluoroscopy-less catheter ablation for AF compared to fluoroscopy-guided ablation. Methods Retrospective observational study of consecutive AF ablations (N=881) conducted at a university teaching hospital (Hamilton Health Sciences, Hamilton, Ontario) from November 2017 to September 2022. An electro-anatomical mapping system and ICE was used in all cases. Baseline characteristics and procedural outcomes between the fluoroscopy-less and fluoroscopy-guided groups were compared. Cases that used &amp;lt;60 seconds of fluoroscopy (occasionally used by operators during the placement of an esophageal probe) were included in the fluoroscopy-less group (N= 68). Results Mean age of individuals was 60.6 ± 11 years, 71.7% were male, 72.6% had paroxysmal AF, mean CHA2DS2-VASc score was 1.6 ± 1.4, 11.1% had prior heart failure, and mean left ventricular ejection fraction was 57.5 ± 15%. There were no significant differences in patient baseline characteristics between the fluoroscopy-less and fluoroscopy groups. Total procedure and fluoroscopy times were lower in the fluoroscopy-less group compared to the fluoroscopy-guided group (169.3 ±42 minutes vs. 192.1 ±54 minutes, p&amp;lt;0.0001 and 0.024 ±0.10 vs. 10.0 ±7.4 minutes , p&amp;lt;0.0001). Fluoroscopy-less AF ablation remained an independent predictor of lower procedure times following adjusting for the use of general anesthesia, high-power short-duration, presence of trainees, AF pattern, redo cases, and type of mapping system. Complication rates were similar between fluoroscopy-less and fluoroscopy-guided ablation (1.9% vs. 3.8%, p=0.11). Conclusion Fluoroscopy-less catheter ablation for AF appears to have similar procedural outcomes and safety than fluoroscopy-guided AF ablation.

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.

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).

Participation of epicardial connection in transverse conduction across the crista terminalis in patients with upper and lower loop reentry atrial tachycardias

Abstract Background The crista terminalis (CT) sometimes serves as a partial or complete conduction barrier, which is rate- and site-dependent. The basis, location and extent of the transverse conduction across the CT have been controversial. The pseudo-focal activation pattern indicates passive activation from the anatomically opposite chamber or structure. We previously reported cases of transverse CT conduction exhibiting a pseudo-focal activation pattern, indicating the CT conduction utilizing an epicardial connection (EC) in patients with upper loop reentry (ULR) atrial tachycardia (AT). Purpose This study aimed to investigate the prevalence and characteristics of transverse CT conduction using a high-resolution electroanatomical mapping system during CT-dependent AT and to compare between the ULR and lower loop reentry (LLR) ATs. Methods A total of 119 consecutive patients with macroreentrant AT were studied. The diagnosis of ULR/LLR AT was made based on endocardial activation mapping and entrainment pacing obtained from various sites around the superior/inferior vena cava. Transverse CT conduction utilizing an EC was defined as follows; (1) a centrifugal activation pattern with the earliest activation (EA) site &amp;gt;5 mm away from the CT, (2) later activation observed between the EA and the CT, and (3) the EA site exhibiting a pseudo-focal activation pattern (multiple breakthroughs or a small r wave on unipolar electrogram). Results Eighteen (15.1%) of the 119 patients were diagnosed with CT-dependent AT (15 men; median age, 71.5 years; AT cycle length, 265 ms; left atrial diameter, 42.5 mm; left ventricular ejection fraction, 49%). The 18 patients were divided into 2 groups: 9 patients with ULR and 9 with LLR AT. There were no significant differences in clinical characteristics (sex, history of cardiac surgery and organic heat disease) between ULR and LLR groups. Transverse CT conduction utilizing EC was more frequently observed in the ULR group than in the LLR group [77.8% (7/9) vs 22.2% (2/9), P=0.05]. In all patients with transverse CT conduction utilizing EC, scars extended along the CT. AT cycle length was significantly longer in the ULR group than in the LLR group (295 vs 235 ms, p=0.001). All ATs were successfully eliminated by radiofrequency ablation at the breakthrough sites and/or along the CT in ULR patients or by cavotricuspid isthmus ablation in LLR patients. Conclusions Half (9/18) of the patients with CT-dependent AT exhibited transverse CT conduction with a pseudo-focal activation pattern, suggesting the existence of an EC between the sinus venosus and the right auricle. The high prevalence of the pseudo-focal pattern in patients with the ULR compared to those with the LLR may provide insights into mechanisms.Figure1Figure2

Voltage-Guided and Non-Voltage-Guided Superior Vena Cava Isolation in Patients With Atrial Fibrillation.

In addition to the pulmonary vein, the superior vena cava (SVC) is an important focus of atrial fibrillation (AF). However, SVC isolation may cause serious complications, and appropriate settings and techniques for SVC isolation are lacking. This study enrolled 86 consecutive patients with AF who underwent SVC isolation. Voltage mapping using a multi-electrode catheter and ablation were performed under the guidance of an electro-anatomical mapping system. The lines encircling the SVC were divided into eight anatomic segments on the SVC geometry, and each segment was subjected to voltage-guided (VG) ablation in decreasing order of voltage (starting from the segment with the highest voltage). Non-VG (NVG) ablation was performed anatomically from the anterior wall toward the septum with one-round cautery. A total of 86 cases (66 males, mean age 69 [60, 74], mean CHA2DS2 VASc score 2 [1, 3], 58 paroxysmal AF) with AF were included for ablation. Electrical SVC isolation was successfully achieved in all patients. The length of the myocardial sleeves, as measured from the SVC-RA junction to the end of the local signal, was 37 [28, 45]mm. Major axis of the RA-SVC junction was 15 [13, 17] and minor axis of the RA-SVC junction was 11 [9, 13]. The number of ablation points with VG SVC isolation was fewer than that for NVG SVC isolation (8 [5, 11.5] vs. 11.5 [8.8, 13.3]; p=0.001). The procedure time of VG SVC isolation was greater than that of NVG SVC isolation (259s [154, 379] vs. 167s [115, 222]; p=0.012). There were no significant differences in the complication rates. VG SVC isolation reduced the number of ablation points compared with NVG SVC isolation.

Pulsed Field Ablation to Treat Paroxysmal Atrial Fibrillation: Safety and Effectiveness in the AdmIRE Pivotal Trial.

Evidence from clinical trials of early pulsed field ablation (PFA) systems in treating atrial fibrillation has demonstrated their promising potential to reduce complications associated with conventional thermal modalities while maintaining efficacy. However, the lack of a fully integrated mapping system, a staple technology of most modern electrophysiology procedures, poses limitations in lesion creation and workflow options. A novel variable-loop PFA catheter integrated with an electroanatomic mapping system has been developed that allows for real-time nonfluoroscopic procedural guidance and lesion indexing as well as feedback of tissue-to-catheter proximity. AdmIRE (Assessment of Safety and Effectiveness in Treatment Management of Atrial Fibrillation With the Bosense-Webster Irreversible Electroporation Ablation System), a multicenter, single-arm, Food and Drug Administration investigational device exemption study, evaluated the long-term safety and effectiveness of this integrated PFA system in a large United States-based drug-refractory symptomatic paroxysmal atrial fibrillation patient population. Using the PFA catheter with a compatible electroanatomic mapping system, patients with drug-refractory symptomatic paroxysmal atrial fibrillation underwent pulmonary vein isolation. The primary safety end point was primary adverse event within 7 days of ablation. The primary effectiveness end point was a composite end point that included 12-month freedom from documented atrial tachyarrhythmia (ie, atrial fibrillation, atrial tachycardia, atrial flutter) episodes, failure to achieve pulmonary vein isolation, use of a nonstudy catheter for pulmonary vein isolation, repeat procedure (except for one redo during blanking), taking a new or previously failed class I or III antiarrhythmic drug at higher dose after blanking, or direct current cardioversion after blanking. At 30 centers, 277 patients with paroxysmal atrial fibrillation (61.5±10.3 years of age; 64.3% male) in the pivotal cohort underwent PFA. More than 25% of the procedures were performed without fluoroscopy. Median (Q1, Q3) pulmonary vein isolation procedure, fluoroscopy, and transpired PFA application times were 81.0 (61.0, 112.0), 7.1 (0.00, 14.3), and 31.0 (24.8, 40.9) minutes, respectively. The primary adverse event rate was 2.9% (8 of 272), with the most common complication being pericardial tamponade. The 12-month primary effectiveness end point was 74.6%. The 1-year freedom from atrial fibrillation, atrial tachycardia, or atrial flutter recurrence rate after blanking was 75.4%. Substantial improvements in quality of life were observed as early as 3 months after the procedure, concurrent with a reduction in multiple health care use measures. AdmIRE confirmed the safety and effectiveness of the variable-loop PFA catheter, with short procedure and PFA application times and low fluoroscopy exposure. URL: https://www.clinicaltrials.gov; Unique identifier: NCT05293639.

Invasive management of atrial tachycardias using a novel lattice-tip catheter combining high-density mapping and dual ablation properties: initial real-world experience.

Invasive management of atrial tachycardias(ATs) requires proper diagnosis of the mechanism followed by elimination of the responsible substrate. A novel lattice-tip catheter with both high-density mapping and dual ablation properties(radiofrequency-RF/pulsed field ablation-PFA) has been recently introduced for catheter ablation of atrial fibrillation. We present the first study to assess its performance in the management of ATs (diagnostic and therapeutic). Patients with documented ATs were selected. Activation mapping was used for the establishment of the AT mechanism. Confirmation with entrainment was performed, whenever appropriate. Accuracy of the activation mapping in diagnosis, acute ablation efficacy, and procedural characteristics were the study endpoints. Twenty patients were included (12 cavotricuspid isthmus-dependent atrial flutters, 5 mitral flutters, 2 roof flutters, and 2 focal ATs). Proper diagnosis was established by activation mapping in all cases. The mean mapping time was 7.85 ± 3.06 min with 296.82 ± 150.9 mean mapping points/minute. The mean ablation time was 54.25 ± 42.97 s. Conversion to sinus rhythm during ablation was achieved in all cases with the exception of a roof flutter that converted to mitral flutter and a case of a parahisian AT in which ablation was not attempted. Patients that received ablation did not experience any arrhythmia recurrence in a mean follow up of 4.14 ± 0.91months. No major or minor complications occurred. The lattice-tip catheter and its dedicated electroanatomical mapping system provided sufficiently detailed activation mapping for the diagnosis of the AT mechanism. The delivered lesions were highly effective acutely, with no adverse events. However, limitations exist and should be acknowledged.

Personalized computational electro-mechanics simulations to optimize cardiac resynchronization therapy.

In this study, we present a computational framework designed to evaluate virtual scenarios of cardiac resynchronization therapy (CRT) and compare their effectiveness based on relevant clinical biomarkers. Our approach involves electro-mechanical numerical simulations personalized, for patients with left bundle branch block, by means of a calibration obtained using data from Electro-Anatomical Mapping System (EAMS) measures acquired by cardiologists during the CRT procedure, as well as ventricular pressures and volumes, both obtained pre-implantation. We validate the calibration by using EAMS data coming from right pacing conditions. Three patients with fibrosis and three without are considered to explore various conditions. Our virtual scenarios consist of personalized numerical experiments, incorporating different positions of the left electrode along reconstructed epicardial veins; different locations of the right electrode; different ventriculo-ventricular delays. The aim is to offer a comprehensive tool capable of optimizing CRT efficiency for individual patients. We provide preliminary answers on optimal electrode placement and delay, by computing some relevant biomarkers such as , ejection fraction, stroke work. From our numerical experiments, we found that the latest activated segment during sinus rhythm is an effective choice for the non-fibrotic cases for the location of the left electrode. Also, our results showed that the activation of the right electrode before the left one seems to improve the CRT performance for the non-fibrotic cases. Last, we found that the CRT performance seems to improve by positioning the right electrode halfway between the base and the apex. This work is on the line of computational works for the study of CRT and introduces new features in the field, such as the presence of the epicardial veins and the movement of the right electrode. All these studies from the different research groups can in future synergistically flow together in the development of a tool which clinicians could use during the procedure to have quantitative information about the patient's propagation in different scenarios.

Impact of effective refractory period personalization on arrhythmia vulnerability in patient-specific atrial computer models.

The effective refractory period (ERP) is one of the main electrophysiological properties governing arrhythmia, yet ERP personalization is rarely performed when creating patient-specific computer models of the atria to inform clinical decision-making. This study evaluates the impact of integrating clinical ERP measurements into personalized in silico models on arrhythmia vulnerability. Clinical ERP measurements were obtained in seven patients from multiple locations in the atria. Atrial geometries from the electroanatomical mapping system were used to generate personalized anatomical atrial models. The Courtemanche M. et al. cellular model was adjusted to reproduce patient-specific ERP. Four modeling approaches were compared: homogeneous (A), heterogeneous (B), regional (C), and continuous (D) ERP distributions. Non-personalized approaches (A and B) were based on literature data, while personalized approaches (C and D) were based on patient measurements. Modeling effects were assessed on arrhythmia vulnerability and tachycardia cycle length, with sensitivity analysis on ERP measurement uncertainty. Mean vulnerability was 3.4 ± 4.0%, 7.7 ± 3.4%, 9.0 ± 5.1%, and 7.0 ± 3.6% for scenarios A-D, respectively. Mean tachycardia cycle length was 167.1 ± 12.6 ms, 158.4 ± 27.5 ms, 265.2 ± 39.9 ms, and 285.9 ± 77.3 ms for scenarios A-D, respectively. Incorporating perturbations to the measured ERP in the range of 2, 5, 10, 20, and 50 ms changed the vulnerability of the model to 5.8 ± 2.7%, 6.1 ± 3.5%, 6.9 ± 3.7%, 5.2 ± 3.5%, and 9.7 ± 10.0%, respectively. Increased ERP dispersion had a greater effect on re-entry dynamics than on vulnerability. Inducibility was higher in personalized scenarios compared with scenarios with uniformly reduced ERP; however, this effect was reversed when incorporating fibrosis informed by low-voltage areas. Effective refractory period measurement uncertainty up to 20 ms slightly influenced vulnerability. Electrophysiological personalization of atrial in silico models appears essential and requires confirmation in larger cohorts.

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.

Zero-fluoroscopy catheter ablation of premature ventricular contractions: comparative outcomes from the right ventricular outflow tract and other ventricular sites.

The three-dimensional electroanatomic mapping (EAM) system allows performing catheter ablation (CA) without fluoroscopy in patients with premature ventricular contractions (PVCs). The right ventricle outflow tract (RVOT) location is favorable for performing zero-fluoroscopy CA. Non-RVOT zero-fluoroscopy CA is a challenging procedure. The study aimed to evaluate the efficacy and safety of zero-fluoroscopy CA using the EAM in patients with PVCs from RVOT and non-RVOT. Completely zero-fluoroscopy CA of PVCs guided by EAM was performed in 107 patients with PVCs. 54 patients underwent zero-fluoroscopy RVOT CA. The remaining 53 patients underwent zero-fluoroscopy non-RVOT CA. Demographic and clinical baseline characteristics, procedure parameters, and follow-up were obtained from medical records. Primary outcomes were the acute and the permanent success rate (12-month follow-up), complications, and procedure time. There were no significant differences between groups regarding baseline characteristics. Acute procedural success was achieved in 52 patients (94,44%) in the RVOT zero-fluoroscopy CA group and in 45 patients (86,54%) in the non-RVOT zero-fluoroscopy CA group (ns). A long-term success rate was achieved in 50 patients (90,74%) in the RVOT zero-fluoroscopy CA group and in 44 patients (84,62%) in the non-RVOT zero-fluoroscopy CA group (ns). The median procedure time was 80.5 minutes in the RVOT group and 90 minutes in the non-RVOT group (ns). There were two complications in the non-RVOT group (ns). There were no differences in procedure time efficacy and safety zero-fluoroscopy ablation between RVOT and non-RVOT locations. Non-fluoroscopy CA of PVCs is a feasible, safe, and efficient procedure.

Intermittent hypoxia by obstructive sleep apnea is significantly associated with electro-anatomical remodeling of the left atrium preceding structural remodeling in patients with atrial fibrillation

BackgroundObstructive sleep apnea (OSA) is one of the risk factors for atrial fibrillation (AF). However, the mechanism underlying the atrial structural and electro-anatomical remodeling by OSA has not yet been clearly elucidated. MethodsThis study was conducted in 83 patients who had undergone catheter ablation for AF (49 with OSA and 34 Controls without OSA). The left atrial (LA) maps were created in all the patients using a three-dimensional electro-anatomical mapping system. The LA with a bipolar voltage of <0.5 mV was defined as the low voltage area (LVA); %LVA was defined as the ratio of the LVA to the total surface area of the LA. ResultsThe LVA and %LVA were significantly greater in the OSA group as compared with the Control group, however, there was no difference in the LA area. The 3 % oxygen desaturation index (ODI) was significantly correlated with the %LVA (r = 0.268, P = 0.014), but not with the LA area. Multiple regression analysis with adjustments identified 3 %ODI ≥30 (3.088, 1.078–8.851, P = 0.036) as being significantly associated with the %LVA. ConclusionsIn patients with AF complicated by OSA, significant increase of the LVA, but not of the LA area, was observed. The intermittent hypoxia severity was significantly associated with the LVA. These results suggest that intermittent hypoxia by OSA might be one of the mechanisms of electro-anatomical remodeling of the LA, possibly preceding structural remodeling represented by LA enlargement, in patients with AF.

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.

Initial experience with zero-fluoroscopy pulmonary vein isolation in patients with atrial fibrillation: single-center observational trial

Pulmonary vein isolation (PVI) stands as a widely practiced cardiac ablation procedure on a global scale, conventionally guided by fluoroscopy. The concurrent application of electroanatomical mapping systems (EAMS) and intracardiac echocardiography offers a means to curtail radiation exposure. This study aimed to compare procedural outcomes between conventional and our initial zero-fluoroscopy cases in patients with paroxysmal or persistent atrial fibrillation (AF), undergoing point-by-point PVI. Our prospective observational study included 100 consecutive patients with AF who underwent point-by-point radiofrequency PVI. The standard technique was used in the first 50 cases (Standard group), while the fluoroless technique was used in the subsequent 50 patients (Zero group). The zero-fluoroscopy approach exhibited significantly shorter procedural time (59.6 ± 10.7 min vs. 74.6 ± 13.2 min, p < 0.0001), attributed to a reduced access time (17 [16; 20] min vs. 31 [23; 34.5] min, p < 0.001). Comparable results were found for the number of RF applications, total ablation energy, and left atrial dwelling time. In the Zero group, all procedures were achieved without fluoroscopy, resulting in significantly lower fluoroscopy time (0 [0; 0] sec vs. 132 [100; 160] sec, p < 0.0001) and dose (0 [0; 0] mGy vs. 4.8 [4.1; 8.2] mGy, p < 0.0001). The acute success rate was 100%, with no major complications. Zero-fluoroscopy PVI is feasible, safe, and associated with shorter procedure times compared to the standard approach, even in cases without prior experience in zero-fluoroscopy PVI.

VARIPULSE: A step-by-step guide to pulmonary vein isolation.

The VARIPULSE™ variable-loop circular catheter (VLCC) is a bidirectional, multielectrode catheter that can perform electrophysiological mapping and deliver pulsed field energy through the TRUPULSE™ Generator for the treatment of atrial fibrillation. This ablation system, including the CARTO 3™ three-dimensional electroanatomical mapping system, represents a fully integrated system. Pulsed field ablation (PFA) is a novel, primarily cardiac tissue-selective ablation technology with a minimal thermal effect, potentially eliminating the collateral tissue damage associated with radiofrequency ablation or cryoablation. Integration of a mapping system may lead to shorter fluoroscopy times and improve the usability of the system, allowing tracking of energy density and placement to confirm no areas around the vein are left untreated. This step-by-step review covers patient selection, mapping, the step-by-step ablation workflow, details on catheter repositioning and ensuring contact, considerations for ablation of specific anatomical variations, and discussion of ablation without fluoroscopy based on our initial clinical experience. The VLCC is part of the fully integrated PFA system designed for pulmonary vein isolation, using mapping to guide catheter placement and lesion set creation. The current workflow, which is based on our initial clinical experience, may be further refined as the PFA system is used in real-world settings.

Comparison between Remotely Supported Nurse-led Electro-Anatomic Mapping and Standard Onsite Engineer Support for Electrophysiological Procedures.

Catheter ablations of complex cardiac arrhythmias are currently guided by electro-anatomic mapping systems. The aim of this study was to compare two different approaches: remotely supported nurse-led electro-anatomic mapping with standard onsite engineer support. In this retrospective observational study, 166 patients with complex and non-complex procedures were included. 82 patients benefited from electro-anatomic mapping with remotely supported nurse-led mapping (mean age: 62±16years), while the approach for 84 patients was with standard onsite engineer support (mean age: 56±19 years). Procedural characteristics, acute results and complication rates were compared between both groups and showed similar results.Complex and non-complex procedures were conducted in both groups, including left atrial and ventricular procedures. As ventricular tachycardia and accessory pathway ablations were more frequently conducted with standard onsite engineer support, we separately analyzed the largest subgroup, 105 patients with atrial fibrillation, left atrial flutter and left atrial tachycardia. Patients in this subgroup had comparable baseline characteristics, procedure times and procedural success. Nevertheless, there were longer ablation times and more utilization of fluoroscopy in the onsite group, most likely due to more complex procedures. Our results underline the practicality of remotely supported nurse-led electro-anatomic mapping. The latter approach proved to be a safe alternative to onsite engineer support. Due to its advantages, particularly for insular settings, it will likely play a greater role in the future.

Longitudinal reduction in fluoroscopy with continued use of 3-dimensional electroanatomic mapping systems in catheter ablation of supraventricular tachycardia – then and now

BackgroundCatheter ablation is a first-line treatment for symptomatic, recurrent supraventricular tachycardia (SVT). This study aims to demonstrate if 3D-electroanatomic mapping (EAM) during SVT ablation reduces fluoroscopy time (FT) and determine if further reductions in FT are observed longitudinally. MethodsAll cases of SVT ablation between May 2011–May 2022 at a single tertiary centre were prospectively recruited. FT between the cohorts with and without EAM were compared. Within the EAM subset, the trend of FT across the years was analysed. ResultsThere were 1758 cases included, 563 without EAM, 1195 with EAM. EAM was associated with a longer procedure time (mean + 8.8 min, p = 0.001), but with mean reductions in FT and dose area product (DAP) by 19.6 min and 18 621 mGy*cm2 respectively (p < 0.001). There was comparable efficacy without any increase in complication rates. Over time (2011–2022), further reduction in FT of 0.9 min year on year was observed (p = 0.001). Between 2011 and 2017, there was a significant reduction in FT of 1.1 min year on year (p = 0.019), which was not observed from 2017 onwards (p = 0.061). The greatest reduction in FT was after the first year of adoption. ConclusionEAM in SVT ablation reduces fluoroscopy use. FT was initially observed to reduce further over time before plateauing, likely due to increased operator experience. While there is increased interest in zero fluoroscopy SVT ablation, complementary use of fluoroscopy may still be necessary in complex cases.

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.