Irrigated-tip Ablation Catheter Research Articles

Abstract 17847: Typical Right Atrial Flutter Ablation Using Subclavian Venous Access in Patients With Interrupted or Occluded Inferior Vena Cava

Introduction: Ablation for typical atrial flutter (AFL) traditionally involves vascular access from the femoral vein to facilitate advancing catheters through the Inferior Vena Cava (IVC) to the right atrium (RA). In patients with interrupted or occluded IVC, this procedure is challenging to perform. We report a case series of typical right AFL ablation using subclavian access in interrupted or occluded IVC. Cases: A 63-year-old female with typical AFL refractory to medical therapy was referred for radiofrequency ablation (RFA). She had a history of surgically corrected atrial septal defect at age 4 years with known IVC interruption draining into RA via an azygous venous extension. Another case involved a 41-year-old male with quadriplegia and typical AFL who underwent an attempted RFA from femoral access that was aborted due to massive thrombosis of IVC. Decision making: In both cases, two sheaths were placed into the left subclavian venous system using ultrasound guidance. A coronary sinus catheter and irrigated tip ablation catheter were advanced into the coronary sinus and RA respectively. Additionally, in the second case, an intracardiac echocardiography probe was inserted via separate venous access. Using the electroanatomic mapping system, entrainment and activation mapping confirmed a tricuspid isthmus-dependent AFL. RFA was performed using an open irrigated RFA catheter in a linear fashion resulting in the termination of the tachycardia to sinus rhythm. In the first case, ablation extended from the tricuspid annulus to the os of the hepatic vein at the 06:00 position. Post ablation, hemostasis was achieved using a suture-mediated closure device. At follow-up, both patients were asymptomatic without evidence of AFL on extended-duration cardiac monitoring. Conclusion: In patients with interrupted or occluded IVC, the subclavian veins can be accessed for mapping and ablation of typical AFL when traditional femoral venous access is challenging.

A new workflow including Coherent algorithm in sinus rhythm for the treatment of Ventricular Tachycardia in patients with scar related heart disease

Abstract Funding Acknowledgements Type of funding sources: None. Background Catheter ablation is a well establish therapy in patients with structural heart disease (SHD) and sustain ventricular tachycardia (VT). Scar substrate modification is one of the two endpoint of a VT ablation procedure. Dechanneling is one of the described successful techniques that shown to be effective for substrate modification Aim This is a pilot study aiming to evaluate the feasibility and the acute efficacy of a new mapping approach for VT ablation with the combination of high density (HD) mapping and Coherent mapping algorithm. Methods All enrolled patients underwent radio frequency catheter ablation (RFCA) for drug-refractory VT or VT storm. Before mapping, programmed ventricular stimulation was performed in all patients for the induction of clinical VT or any other ventricular arrhythmias (VA), if VA was inducible, then electrical cardioversion was conducted to restore sinus rhythm. After transseptal puncture, left ventricular (LV) HD mapping was conducted using a 3D mapping system aiming >5000 mapping points during sinus rhythm, intrinsic atrial rhythm, or ventricular pacing with a multielectrode catheter. During HD mapping, all late potentials (LPs) were tagged as double potentials (DP) and all potentials below 0,2 mV were tagged as scar. Then, Coherent mapping was used to visualize electrical propagation through the LV, based on velocity vector identification, highlighting how the electrical signal enters the scar and identifying the "entrance points" (EP). RFCA was delivered in a power-controlled mode on all the individuated EPs using an open, irrigated-tip ablation catheter with contact force sensor. After RFCA, a second remap was conducted to evaluate the LPs abolition. Then, a programmed ventricular stimulation was performed to validate non inducibility of any VAs. Results 10 consecutive patients (age 71,25±10,32 years, 100% male) undergoing RFCA for drug-refractory VT or VT storm (50%). Acute procedural end-point were: abolition of the LPs and non-inducibility of any VA at the end of the procedure. Abolition of LPs was reached in all cases while non inducibility was reached in 9 patients (90%). Mean procedural time was 214±33,81 min, mean mapping time was 89±15,40 min with mean number of acquired points of 5218±359,56. Mean fluoroscopy time and dose were 15±33,81 min and 5218±7149,8 µGm2, respectively. Mean entrance points identified was 2,6±0,84. In 5 patents (50%), after ablation a modification in the refractory period of the left ventricular myocardium was observed. Mean RF time was 1216±565,46 seconds, with mean number of Visitag of 33±29,98. No acute complication were reported. Conclusion High-density mapping in sinus rhythm combined with Coherent algorithm facilitates the understanding of the substrate and provides targets for effective ablation. This approach has been proven safe and with high acute success rates.

Epicardial ablation of left atrial flutter

Abstract Funding Acknowledgements Type of funding sources: None. Background Left atrial flutter (LAFL) may have epicardial components not accessible to endocardial ablation by radiofrequency (RF) application. Subxiphoid access to the pericardial space has been reported in isolated cases. Purpose to prospectively evaluate the efficacy and safety of subxiphoid access to the pericardial space to map and ablate LAFL refractory to endocardial RF application. Methods Patients with LAFL confirmed by activation and entrainment mapping and refractory to endocardial RF application were consecutively enrolled. An epicardial component of the tachycardia circuit was suspected when parts of the AFL activation, channels of slow conduction or conduction gaps on previous ablation lines intersecting the AFL circuit were not found. Pericardial access was obtained by subxiphoid puncture performed conventionally or facilitated by saline infusion or CO2 insufflation into the pericardial space. Following pericardial access, epicardial mapping and ablation was performed with a conventional RF irrigated tip ablation catheter. All procedures were performed under oral anticoagulation and during following heparin infusion for 350 sec activation clotting time target. Results 15 patients with 18 LAFL were included (61.0 ± 8.8 years, 80% male). 14 patients have had a previous atrial fibrillation (AF) ablation. Epicardial ablation was attempted after a previous LAFL endocardial ablation procedure in 6 patients and during the same endocardial ablation procedure in the last 9 patients. Pericardial access was not achieved in 1 patient due to pericardial adhesions (after prior cardiac surgery). Ablation was successfully performed in 11 patients (73.33%) and failed in 4 patients with perimitral AFL (1 patient also had a peri-left appendage AFL). The successful ablation site was found in the transverse sinus of Theile over the Bachmann bundle in 14 patients with perimitral, septal and anterior-wall LAFL and in the oblique sinus in a posterior-wall LAFL. No patient presented relevant complications except for 2 patients who presented hemopericardium and 1 with delayed cardiac tamponade following accidental RV puncture and who required pericardiocentesis. No patient presented AFL recurrences at 19.8 months (range 6-34 months) follow-up except for 2 patients in whom ablation failed or pericardial access was not achieved. Conclusions Epicardial ablation of LAFL refractory to endocardial ablation is successful in most patients following successful pericardial access. This approach appears associated with low risk of significant complications.

PO-01-041 COMPARISON OF DIFFERENT POWER SETTINGS (40W VS 50W) IN HIGH-POWER SHORT-DURATION RADIOFREQUENCY ABLATION FOR PAROXYSMAL ATRIAL FIBRILLATION: ACUTE AND LONG-TERM CLINICAL OUTCOMES

The REAL-AF registry is a prospective multi-center registry designed to obtain real-world clinical experience of atrial fibrillation (AF) ablations. While pulmonary vein isolation (PVI) can be performed successfully with various power settings, there has been a recent surge of interest in delivering higher power short duration (HPSD) lesions using 40W-50W through the irrigated tip ablation catheters. However, the ideal power setting to deliver HPSD lesions is unknown. Compare the procedural characteristics, safety and long-term all-atrial arrhythmia recurrence between patients undergoing HPSD radiofrequency ablation either using 40W or 50W. We analyzed the data derived from subjects in the Real-AF registry from January 2018 through May 2021. The patients enrolled underwent a first-time catheter ablation for paroxysmal AF with a minimum follow-up of 12 months. The sample of patients was dichotomized in procedures using either HPSD 50 W or HPSD 40 W of power, with a target ablation index (AI) in the anterior wall of 500-550 and posterior wall of 400 for both groups. We used unadjusted bivariate analyses to explore the relationship between power delivery, patient characteristics and procedural and 12-month clinical outcomes. A total of 385 patients were included in the analyses. There were no significant differences in patient characteristics between groups (Table 1). The HPSD 50W group had significantly shorter RF time (18.69 vs. 29.21, p<0.001) and procedural time (77.72 vs. 99.98, p<0.01) when compared to the LPLD group. There were no statistically significant differences between HPSD 50 W and HPSD 40W for first-pass PVI and no clinically significant differences in the target ablation index between the groups. When looking at all -atrial arrhythmia recurrence documented post-blanking period at 12 months, there was no statistically significant relationship (p=0.925) between groups. There was no statistically significant relationship between immediate procedural complications, pericarditis, or complications at 12 months post-ablation (p>0.05). The esophageal temperature measurements were not different between groups. HPSD is a safe and effective way of performing radiofrequency ablation of AF. HPSD using 50W was associated with shorter RF ablation and procedural times when compared to HPSD 40W without increase in complications HPSD 50W and HPSD 40W had similar acute and long-term success rates.

PO-05-232 SAFETY AND EFFICACY OF ATRIOVENTRICULAR NODAL REENTRY TACHYCARDIA ABLATION USING AN IRRIGATED CONTACT FORCE CATHETER

Atrioventricular Nodal Reentry Tachycardia (AVNRT) ablation is a common procedure in contemporary electrophysiology practice. Traditionally ablation for AVNRT has been performed with non-irrigated catheters, guided by fluoroscopy and intracardiac electrograms. Increasingly electroanatomic mapping systems are utilized to allow for low or zero fluoroscopy procedures. Contact force catheters can provide information on tissue contact and stability that can be helpful in patients with challenging anatomy. Available contact force catheters are irrigated and concern has existed for using irrigated tip ablation catheters for AVNRT ablation due to the potential to create lesions that are too deep and could increase the risk for AV block. To describe the safety and efficacy for the use of irrigated contact force catheters for ablation of AVNRT Review of procedural data from patients undergoing radiofrequency ablation for AVNRT using electroanatomical mapping combined with irrigated contact force catheter. Fifty patients from 4 regions across Australia were included. Procedures were performed by 9 experienced electrophysiologists. No periprocedural complications occurred. Procedural success was achieved in 96%. Median lesion contact force (25-75 centile) was 4.0(2-6)g. Peak power was set at 50W, median baseline irrigation was at 2ml/min and 6ml/min during ablation. Median number of lesions was 9(4.5-17.5); with total ablation time of 203(95-366) seconds. 60% of the cases were performed without fluoroscopy. Ablation of AVNRT using an irrigated contact force catheter on low irrigation setting is safe and effective. Contact force catheters using low irrigation settings may safely improve success rates in AVNRT with challenging anatomy or ablation of other substrate in close proximity to vital structures.

AV-node isolation as an alternative to AV-node ablation in patients undergoing pace & ablate strategy.

Atrioventricular (AV)-node ablation (AVNA) is a common therapy option for rate control strategy of permanent atrial fibrillation (AF). We hypothesized that isolation of the AVnodal isolation(AVNI) is associated with a more frequent preservation of an adequate escape rhythm compared to AVNA. This retrospective study included 20 patients with therapy-refractory AFbeing treated with AVNI and 40 historical AVNA-controls. In AVNI the AV-node region was mapped using a 3D mapping system. Ablation was performed around the previously mapped HIS-cloud regions isolating the atrium from the AV-node. In the AVNI group, ablation was performed with irrigated tip ablation catheter in all cases. The two approaches were compared regarding rate of escape rhythm, delta QRS, and procedural data. The number of patients with adequate escape rhythm in AVNI was significantly superior to AVNA immediately postoperative (90% vs. 40%, p < 0.01) and during follow-up (77% vs. 36%, p < 0.05). The median change in QRS width was 0 ms in AVNI versus +26 ms in AVNA (p < 0.01). Thirty percent new bundle branch blocks in AVNA were observed compared to 0% in AVNI (p < 0.01). In the AVNI group, fluoroscopy time and total dose area product were significantly lower (p < 0.01). The present study suggests that AV-node isolation using 3D navigation mapping system is a feasible and effective alternative to conventional AVNA. The precise application of radiofrequency lesions preserves a stable AV-junctional rhythm.

PO-717-05 PROPHYLACTIC AND PREVENTIVE RADIOFREQUENCY SEPTAL ABLATION TO REDUCE THE POSSIBILITY OF LEFT VENTRICULAR OUTFLOW TRACT OBSTRUCTION POST-MITRAL VALVE REPLACEMENT

The patients who have severe mitral annulus calcification leading severe mitral stenosis often are eldery and have comorbidities which increase surgical risk of stroke, embolization, and bleeding complications. Radiofrequency ablation is another prophylactic and preventive option for reducing the possibility of left ventricular outflow tract obstruction (LVOTO) post-mitral valve replacement patients who are not suitable for surgical myomectomy or alcohol septal ablation. N/A We report on a 78-year-old woman with a history of symptomatic severe mitral valve stenosis with a mean gradient of 20 mmHg. She was not a surgical candidate for mitral valve and preparing for a valve-in-valve percutaneous mitral valve replacement. Computer tomography revealed left ventricular septal bulge appeared to have a significant LVOTO post-valve replacement. However she was not a candidate for surgical myomectomy due to her age and comorbidities, and she also had no anatomical option to consider for alcohol septal ablation. Heart team discussion decided to do radiofrequency ablation (RFA) to reduce the possibility of LVOTO post-valve replacement. RFA was performed in the left ventricular outflow tract (LVOT) using an irrigated-tip ablation catheter; the target site was identified along the LV septal hypertrophy using intracardiac echocardiography (ICE) and electroanatomical CARTO mapping. ICE demonstrated thinning of the ablated regions. The LV electrograms were noted during ablation and the size was decreasing from 0.63 mV to 0.15 mV. After RFA, she underwent minimally invasive open left-atrial transcatheter mitral valve replacement-in-MAC via right minithoracotomy with a 29-mm Edwards Sapien 3 bioprosthetic valve. Transthoracic echocardiography after surgery showed normal left ventricular systolic function with a mean mitral valve pressure gradient of 5.63 mmHg and no paravalvular leakage. The LVOT resting gradient of 17 mmHg. LVOTO could be one of the complications after valve replacement. Radiofrequency septal ablation is a novel prophylactic and preventive procedure in reducing the possibility of the left ventricular outflow tract obstruction post-mitral valve replacement and decreasing the risk of morbid and mortality.View Large Image Figure ViewerDownload Hi-res image Download (PPT)

Radiofrequency ablation in Brugada syndrome.

Radiofrequency ablation in Brugada syndrome.

B-AB04-03 RADIOFREQUENCY ENERGY APPLICATIONS TO TREAT INCOMPLETE LEFT ATRIAL APPENDAGE CLOSURE IN WATCHMAN PATIENTS WITH PERI- OR POST-PROCEDURAL EVIDENCE OF A SIGNIFICANT RESIDUAL LEAK

Incomplete left atrial appendage closure (LAA) due to significant residual leaks may be observed either acutely and/or chronically after Watchman implantation. Endothelial denudation by means of radiofrequency energy (RF) applications has been proven to prevent recanalization of intracranial aneurysms after coil embolization, thereby favoring complete sealing. In vitro and in vivo experiments have demonstrated that endothelial denudation promotes collagen deposition and tissue retraction. To evaluate the safety and efficacy of RF delivery targeting the atrial side of a significant residual leak in patients with acute and chronic evidence of incomplete percutaneous LAA occlusion. Forty-three patients (mean age: 75±7 yrs; CHA2DS2-VASc: 4.6±1.4; HAS-BLED: 4.0±1.1) with a significant residual LAA leak after Watchman implantation were enrolled. All had transesophageal echocardiographic (TEE) evidence of a leak ≥ 4mm after Watchman deployment and received multiple RFAs targeting the atrial side of the leak. Peri-Watchman ablation was performed under TEE/ICE guidance using a 3.5mm open irrigated-tip ablation catheter. Follow-up TEE was performed approximately 45 days after the procedure. Incomplete LAA occlusion was documented acutely after Watchman deployment in 19 (44.2%) patients, 4 (9.3%) of whom had a Watchman FLX implanted. In the remaining 24 (55.8%) patients, a significant residual leak was documented at the time of a routine follow-up TEE. The median leak size was 5mm (range: 4-7). On average, 18±7 RF applications per patient (mean max contact force: 16±3g, mean power: 44±2W, RF time: 5.1±2.5min) were performed targeting the atrial edge of the leak. Post-RF median leak size was 0 mm [0-2]. No peri-procedural complications were observed. Follow-up TEE revealed complete LAA sealing in 23 (53.5%) cases and a negligible residual leak (1-2mm) in 15 (34.9%). No device dislodgments or thromboses were documented. RF applications targeting the atrial edge of a significant peri-Watchman leak may promote LAA sealing via tissue remodeling, without increasing complications.

AV-node isolation in atrial fibrillation vs AV-node ablation by pace and ablate strategy

Abstract Funding Acknowledgements Type of funding sources: None. Introduction AV-node ablation (AVNA) is a common therapy option for rate control strategy of permanent atrial fibrillation. However, this therapy has numerous side-effects as bundle branch blocks and absence of escape rhythm. We have invented a new technique that isolates the AV node instead of ablation. Methods Our study includes 60 patients with 40 being treated with AVNA and 20 being treated with AV-node isolation (AVNI). In AVNI patient´s AV-node region was mapped using 3D navigation system. Ablation was performed around the previously mapped HIS-cloud regions isolating the atrium from the AV-node. In all cases in AVNI group ablation was performed with irrigated tip ablation catheter. Procedure time, ablation points, fluoroscopy time and total DAP, escape rhythm and delta QRS among other data were measured and compared in these two methods. Statistical analysis was performed by SPSS software 27.0. Results No complications appeared in this study. In the AVNI group more ablation points were used (p &amp;lt; 0.01) but there was no significant difference in total procedure time (p = 0.730). With AVNI highly significantly less fluoroscopy time (1.4 vs. 4.7 minutes) and total DAP (40.75 vs. 382.85 µGym²) was achieved (p &amp;lt; 0.01). Moreover, the median change in QRS width was 0 ms in the AVNI group vs. 26 ms in the AVNA group (p &amp;lt; 0.01). Immediately postoperative the escape rhythm of the AVNI group was significantly higher than in the AVNA group (MRang = 37.38 vs. MRang = 27.06, p = 0.023). Conclusion AV-node isolation using 3D navigation mapping system is a safe and effective alternative to classic AVNA procedure with less radiation exposure and potential preservation of escape rhythm, which is a major benefit in case of a pacemaker failure. Figure 1. 3D Navigation pictures after successful AVNI with NavX-System (left panel) and CARTO 3-System (right panel). His cloud with yellow points. The Tricuspid annulus could be defined with different color (green on the left panel) or with the tag points (white points on the right panel). Modified left lateral to posterior view. Abstract Figure.

Pre-procedural arrhythmia burden and the outcome of catheter ablation of idiopathic premature ventricular complexes.

Radiofrequency catheter ablation of idiopathic premature ventricular complexes (PVCs) is an effective method for eliminating symptoms and preventing/reversing arrhythmia-induced cardiomyopathy. One reason for procedural failure is low PVC frequency during the procedure. We aimed to investigate the relation between pre-procedural PVC burden and outcome of idiopathic PVC catheter ablation. Patients who underwent idiopathic PVC ablation between 2013 and 2019 at two tertiary referral centers were retrospectively included. All procedures were performed using irrigated-tip ablation catheters and a 3D electro-anatomical mapping system. Sustained ablation success was defined as a ≥80% reduction of pre-procedural PVC burden determined by 24h-Holter at follow-up. Overall, 254 patients (median age 54 years [IQR 42-64]; 47% male) were enrolled. The median pre-ablation PVC-burden was 22% (IQR 11-31%), which was reduced to a post-ablation PVC burden of 0.3% (IQR 0-4%) after a median of 90 days. Sustained ablation success was achieved in 182 patients (72%). Pre-procedural PVC burden did not differ between patients with sustained ablation success and recurrence during follow-up (median 21%vs. 22%, p=.76). When assessed in pre-ablation PVC-burden groups of ≤5%, 6-15%, 16-30%, and ≥31%, sustained ablation success was achieved in 67%, 75%, 71%, and 72%, respectively, with no significant difference (p=.89). Sustained ablation outcome for PVC-burden ≤5% versus >5% showed no difference either (67%vs. 72%, p=.52). Pre-procedural Holter-determined PVC burden does not predict the outcome of idiopathic PVC ablation. Thus, catheter ablation may be a reasonable first choice also for patients with symptomatic yet rare PVCs.

Impact of contact force sensing technology on outcome of catheter ablation of idiopathic pre-mature ventricular contractions originating from the outflow tracts.

Catheter ablation of frequent idiopathic pre-mature ventricular contractions (PVC) is increasingly performed. While potential benefits of contact force (CF)-sensing technology for atrial fibrillation ablation have been assessed in several studies, the impact of CF-sensing on ventricular arrhythmia ablation remains unknown. This study aimed to compare outcomes of idiopathic outflow tract PVC ablation when using standard ablation catheters as opposed to CF-sensing catheters. In a retrospective multi-centre study, unselected patients undergoing catheter ablation of idiopathic outflow tract PVCs between 2013 and 2016 were enrolled. All procedures were performed using irrigated-tip ablation catheters and a 3D electro-anatomical mapping system. Sustained ablation success was defined as a ≥80% reduction of pre-procedural PVC burden determined by 24 h Holter ECG during follow-up. Overall, 218 patients were enrolled (median age 52 years, 51% males). Baseline and procedural data were similar in the standard ablation (24%) and the CF-sensing group (76%). Overall, the median PVC burden decreased from 21% (IQR 10-30%) before ablation to 0.2% (IQR 0-3.0%) after a median follow-up of 2.3 months (IQR 1.4-3.9 months). The rates of both acute (91% vs. 91%, P = 0.94) and sustained success (79% vs. 74%, P = 0.44) were similar in the standard ablation and the CF-sensing groups. No differences were observed in subgroups according to arrhythmia origin from the RVOT (65%) or LVOT (35%). Complications were rare (1.8%) and evenly distributed between the two groups. The use of CF-sensing technology is not associated with increased success rate nor decreased complication rate in idiopathic outflow tract PVC ablation.

235Anatomic guided ablation of the right ganglionated plexus is enough for cardiac autonomic denervation in patients with significant bradyarrhythmias

Abstract Background In patients with significant bradyarrhytmias, cardiac denervation is an alternative therapeutic approach. Previous reports proposed different methods (as high frequency ednocardial stimulation of ganglionated plexus and specific atrial electrogram identification) and targets (right and left atrial ganglionated plexus) for adequate denervation. There is no consensus on the best way to perform these procedures, in spite the right atrial ganglia plexus (GP) ablation seeming to be the most contributive to its success. Purpose To assess the results of a purely anatomic approach for ablation of just the right atrial plexus in patients with severe vagal bradyarrhytmias. Methods We enrolled patients referred for ablation of cardiac parasympathetic ganglia, with or without atrial fibrillation ablation. We performed eletroanatomic mapping of the right and left atria and used an irrigated tip catheter for ablation, aiming at the anterior right GP at the right pulmonary veins antrum along with ablation at the superior vena cava junction and the inferior right GP at the posterior aspect of the right inferior pulmonary vein along with ablation of the right aspect of the interatrial septum, between the posterior wall and coronary sinus ostium (Figure 1). We assessed the PW and Wenckenback cycle lengths (CL) pre and post procedure in patients with sinus arrest or AV block, respectively, and the patients had new 24h holter readings at least 30 days from the index procedure. Results We enrolled 12 patients: 9 males (75%), median age of 49,5 years (IQR 36-61,75). All patients had structurally normal hearts. 7 patients had only ablation of the parasympathetic ganglia and 5 patients had simultaneous pulmonary vein isolation for previously documented atrial fibrillation. 7 patients (58,3%) had sinus bradycardia (2 patients had sinus arrest with pauses of 8 and 13 seconds), 2 patients with cardioinhibitory syncope (with pauses of 23 and 28 seconds) and 3 patients had transient high degree AV block. The ablation procedure led to a median sinus rate acceleration of 15 bpm (IQR 3-29), a median decrease of 320 ms in PW (IQR 23,75-609,5) in patients with sinus arrest and a decrease of 80 ms in wenckenback CL (IQR 60-200) in patients with AV block. With a median follow up of 133,50 days (IQR 36-61,75), no patient had recurrence of symptoms or conduction disturbances. Conclusions In selected patients with severe functional paroxysmal bradyarrhytmias, cardiac denervation using an ablation strategy purely based on anatomic aspects and targeting only the right GP, seems to be an effective therapeutic approach. Abstract Figure 1: Abl of right ganglionated plex

Effect of Renal Denervation and Catheter Ablation vs Catheter Ablation Alone on Atrial Fibrillation Recurrence Among Patients With Paroxysmal Atrial Fibrillation and Hypertension

Renal denervation can reduce cardiac sympathetic activity that may result in an antiarrhythmic effect on atrial fibrillation. To determine whether renal denervation when added to pulmonary vein isolation enhances long-term antiarrhythmic efficacy. The Evaluate Renal Denervation in Addition to Catheter Ablation to Eliminate Atrial Fibrillation (ERADICATE-AF) trial was an investigator-initiated, multicenter, single-blind, randomized clinical trial conducted at 5 referral centers for catheter ablation of atrial fibrillation in the Russian Federation, Poland, and Germany. A total of 302 patients with hypertension despite taking at least 1 antihypertensive medication, paroxysmal atrial fibrillation, and plans for ablation were enrolled from April 2013 to March 2018. Follow-up concluded in March 2019. Patients were randomized to either pulmonary vein isolation alone (n = 148) or pulmonary vein isolation plus renal denervation (n = 154). Complete pulmonary vein isolation to v an end point of elimination of all pulmonary vein potentials; renal denervation using an irrigated-tip ablation catheter delivering radiofrequency energy to discrete sites in a spiral pattern from distal to proximal in both renal arteries. The primary end point was freedom from atrial fibrillation, atrial flutter, or atrial tachycardia at 12 months. Secondary end points included procedural complications within 30 days and blood pressure control at 6 and 12 months. Of the 302 randomized patients (median age, 60 years [interquartile range, 55-65 years]; 182 men [60.3%]), 283 (93.7%) completed the trial. All successfully underwent their assigned procedures. Freedom from atrial fibrillation, flutter, or tachycardia at 12 months was observed in 84 of 148 (56.5%) of those undergoing pulmonary vein isolation alone and in 111 of 154 (72.1%) of those undergoing pulmonary vein isolation plus renal denervation (hazard ratio, 0.57; 95% CI, 0.38 to 0.85; P = .006). Of 5 prespecified secondary end points, 4 are reported and 3 differed between groups. Mean systolic blood pressure from baseline to 12 months decreased from 151 mm Hg to 147 mm Hg in the isolation-only group and from 150 mm Hg to 135 mm Hg in the renal denervation group (between-group difference, -13 mm Hg; 95% CI, -15 to -11 mm Hg; P < .001). Procedural complications occurred in 7 patients (4.7%) in the isolation-only group and 7 (4.5%) of the renal denervation group. Among patients with paroxysmal atrial fibrillation and hypertension, renal denervation added to catheter ablation, compared with catheter ablation alone, significantly increased the likelihood of freedom from atrial fibrillation at 12 months. The lack of a formal sham-control renal denervation procedure should be considered in interpreting the results of this trial. ClinicalTrials.gov Identifier: NCT01873352.

Long-term outcomes after low power, slower movement versus high power, faster movement irrigated-tip catheter ablation for atrial fibrillation

High power, shorter duration (HPSD) ablation strategies have been advocated to increase efficacy and minimize posterior wall deep tissue thermal injury during atrial fibrillation (AF) ablation. The purpose of this study was to determine the long-term outcomes of arrhythmia-free survival from AF and atrial flutter (AFL) between HPSD and low power, longer duration (LPLD) ablation strategies. Of a total of 1333 first time AF ablation procedures with 3 years of follow-up, propensity-matched populations for baseline risk factors were created, comprising 402 patients treated with LPLD ablation (30 W for 5 seconds: posterior wall; 30 W for 10-20 seconds: anterior wall) and 402 patients treated with HPSD ablation (50 W for 2-3 seconds: posterior wall; 50 W for 5-15 seconds: anterior wall). AF/AFL outcomes after a 90-day blanking period were assessed. HPSD ablation was associated with shorter procedure and fluoroscopy times (P < .0001 for both). The recurrence of AF at 1 year (12.9% vs 16.2%; P = .19) and 3 years (26.5% vs 30.7%; P= .23) was similar between LPLD and HPSD groups. AFL was higher at 1 year (7.2% vs 11.2%; P = .03) and 3 years (16.1% vs 21.8%; P= .06; P = .04 after multivariate adjustment) with HPSD ablation. Patients who underwent an LPLD approach had lower rates of need for repeat ablation (21% vs 30%; P = .002). Long-term freedom from AF rates were not significantly different between both approaches. An HPSD ablation strategy compared with an LPLD approach was associated with an increased risk of AFL and need for repeat ablation but with lowered procedure times.

Efficacy and safety of catheter ablation of atrioventricular nodal re-entrant tachycardia by means of flexible-tip irrigated catheters.

Irrigated-tip ablation catheters increase safety and efficacy of ablation procedures, but their use in atrioventricular nodal re-entrant tachycardia (AVNRT) ablation has not been systematically evaluated. The aim of this study is to evaluate the safety and efficacy of radiofrequency (RF) catheter ablation of AVNRT by means of the novel flexible-tip open-irrigated catheter FlexAbility™ and a 3D electroanatomic mapping (EAM) system. This is a single-center and single-operator study on 80 patients referred for AVNRT catheter ablation. Outcome included acute and long-term procedural success as well as complications reported over a median follow-up of 19months (interquartile range 6-24months). Acute success was achieved in all 80 patients. One procedure-related major complication, involving the vascular access, occurred. Mean fluoroscopy time was 106 ± 71s. One patient (1.2%) suffered long-term AVNRT recurrence. Five patients (6.2%) underwent ablation for AVNRT combined with ablation for other clinical arrhythmias. Irrigated RF ablation of AVNRT by means of the novel flexible-tip open-irrigated catheter associated to 3D EAM system is effective and safe. Success rates are comparable to those of other techniques. Complication rate is very low.

Coupled Beats After AV Node Ablation: What is the Mechanism?

An 83 year old lady was highly symptomatic from paroxysmal Atrial Fibrillation (AF) despite numerous antiarrhythmic and rate-limiting medications. Given her preserved left ventricular function, a pace and ablate strategy was pursued. Ablation of the AV node proved challenging requiring 2 procedures with apparently stable AV block and regular escape at 40bpm after the first sitting. Persistent Right Bundle Branch Block (RBBB) was created prior to AV node block at the first sitting. Two irrigated-tip ablation catheters (Coolflex, medium curve, St Jude’s Medical, MN, USA) were placed on either side of the interventricular septum but with the intention to ablate the AV node from the left. Identification of the His bundle from the left proved difficult as the patient was now in AF. Instead the left bundle was targeted and complete AV block achieved by combined Right Bundle Branch (RBB) and Left Bundle Branch (LBB) ablation.

Early and Delayed Alteration of Atrial Electrograms Around Single Radiofrequency Ablation Lesion.

Purpose: The acute effect of radiofrequency (RF) ablation includes local necrosis and oedema. We investigated the spatiotemporal change of atrial electrograms in the area surrounding the site of single standardized pulse of RF energy.Methods: The study enrolled 12 patients (45–67 years, 10 males) with paroxysmal atrial fibrillation (AF) undergoing ablation procedure with irrigated-tip ablation catheter and 3D navigation. The high-density mapping/remapping (129 ± 63 points) within the circular area with radius of ~10 mm, centered at the pre-specified posterior left pulmonary vein antrum ablation site was performed at baseline, immediately after single RF energy delivery (25 W, 30 s, 20 ml/min) and after 30 min waiting period. Bipolar voltages of atrial electrograms (A-EGM-biV) were averaged within the central and 12 adjacent left atrium segments and their relative change was studied.Results: After the ablation, overall A-EGM-biV within the mapping zone (3.51 ± 1.89 mV at baseline) reduced to 2.83 ± 1.77 mV (immediately) and to 2.68 ± 1.58 mV (after 30 min waiting period). In per-segment pair-wise comparison, we observed highly significant change in A-EGM-biV that extended up to the distance of 8.8 mm from the lesion core. The maximum early A-EGM-biV attenuation by 39–49% (P < 0.001) was registered in segments adjacent to pulmonary vein ostia. The subsequent (delayed) A-EGM-biV reduction by 17–24% (P < 0.05) was observed in opposite direction from the lesion center.Conclusions: Significant alteration of atrial electrograms was detectable rather distant from the central lesion. Spatiotemporal development of ablation lesion was eccentric/asymmetric. While acute A-EGM-biV reduction can be attributed predominantly to direct thermal injury, delayed effects are probably due to oedema progression.

Clinical Impact of Saline Volume Infused Through Irrigated-Tip Ablation Catheter in Low Acuity Paroxysmal Atrial Fibrillation Ablation Patients.

Radio-Frequency ablation (RFA) to achieve pulmonary vein isolation (PVI) remains mainstay therapy for symptomatic paroxysmal atrial fibrillation (PAF). The clinical consequences of large saline infusions during AF ablation have not been systematically studied. We utilized the differential flow-rates of the two commercially available ablation catheters (AC): 'ThermoCool' (TCAC) and 'Surround Flow' (SFAC) from Biosense-Webster to evaluate the clinical impact of the saline infused in the immediate post-ablation period. Consecutive charts of PAF patients between 18 and 81 years who underwent RFA procedure at a tertiary care hospital were reviewed. Forty-seven patients were included in the study (33Males, 65±11years, LVEF 58±7% and left atrial diameter 44±7.5mm, 23TCAC-use). The saline volume infused through the AC was significantly higher with TCAC vs SFAC use (1277±316vs697±299 ml; p<0.001), with no difference in volume infused from other sources, total procedure or RFA times (p>0.05). This led to significant increase in post-ablation weight gain (96±23 vs 97.5±24kg; p=0.002), furosemide usage (39% vs 0%; p=0.0006), urine production (120±79 vs 63±31ml/hr; p=0.003) and post-RFA potassium reduction (4.4±0.42 vs 4±0.32mmol/l; p<0.001) with TCAC use. Significant post-RFA reduction in magnesium, calcium and creatinine, associated hyperchloremic metabolic acidosis and a modest QTc prolongation were also observed with use of both ACs albeit only moderate to weakly correlated with saline volume infused through the AC. No clinical adverse outcomes were encountered. Higher saline-volume infusing AC use in PAF ablation causes significant post-ablation weight gain despite higher furosemide use, larger urine production and associated post-RFA potassium reduction without increasing morbidity in lower acuity patients. Furthermore, an array of post-ablation electrolyte disturbances causes a modest and clinically insignificant QTc prolongation.

Persistent left superior vena cava as an arrhythmogenic source in atrial fibrillation: results from a multicenter experience.

Persistent left superior vena cava (PLSVC) is one of the most frequently reported congenital anomalies and may be an important source of trigger of atrial fibrillation (AF). This was a multicenter retrospective experience including 28 patients with PLSVC who were referred for catheter ablation for drug-refractory symptomatic AF. Pulmonary vein and PLSVC isolation were performed (3.5-mm open irrigated tip ablation catheter at maximum power of 20W, maximum temperature 43°C with flow rate of 17ml/min). Clinical outcomes such as complications and long-term freedom from AF were measured. The mean age of the population was 61 ± 8years, 21% were females, and AF duration was 60 ± 33months. Sixty-one percent paroxysmal AF (17/28), 25% (7/28) persistent AF, and 14% (4/28) had long-standing persistent AF. There were no major complications that required any intervention. PLSVC isolation was achieved in 96% (27/28). Freedom from AF at 1year without antiarrhythmic drugs was seen in 75% (21/28) of patients. In PLSVC patients with AF, segmental isolation of PLSVC appears to be feasible and safe and can translate into favorable clinical outcomes.