Open-irrigated Tip Research Articles

Local impedance technology for effective PVI with a novel ablation catheter: results from a large, international, multicenter registry

Abstract Funding Acknowledgements Type of funding sources: None. Background Highly localized impedance (LI) measurements in combination with a catheter-tissue contact force (CF) during atrial fibrillation (AF) ablation may improve tissue characterization and lesion prediction during pulmonary vein isolation (PVI). Purpose This analysis explores the relationship between LI parameters, ablation spot locations and procedural success during ablation of PVs in a large population of consecutive AF patients. Methods Two-hundred twelve consecutive patients from 16 European centers undergoing de novo AF radiofrequency (RF) catheter ablation with a novel open-irrigated tip catheter enabled by CF and LI measurement capabilities (Stablepoint) were included. Ablation was guided by the magnitude and time-course of LI drop during RF delivery. The interlesion distance between each ablation spot was set ≤6 mm. First pass isolation (FPI) was defined as successful PVI at or before completion of the first encircling lesion set regardless of visual gaps. Procedural endpoint was the achievement of the PVI as assessed by entrance and exit block. Data are reported as mean±SD. Results A total of 13891 ablation spots performed around PVs were analyzed (baseline LI=161.2±19 Ω; LI drop=21.9±9 Ω; LI drop rate=3.1±2 Ω/s; RF Delivery time=9.2±4 s; CF=12.5±7 g). LI drop was predicted by baseline LI (r=0.56, 95%CI:0.55 to 0.57, p<0.0001). A total of 80 PV gaps were detected, mostly at the right pairs of the PV (63.7%, p=0.013). The FPI rate per vein was 93.3% resulting from 180 patients (84.9%) with FPI. PV gaps were located at anterior (31.3%), posterior (31%), and carina (16%) sites after the FPI evaluation. At successful ablation spots, both baseline LI and LI drop were larger than at PV gap spots (161.4Ω vs 153.0Ω, p<0.0001 for baseline LI; 22.1Ω vs 14.4Ω, p<0.0001 for LI drop), whereas RF delivery time was shorter (9.1s at successful ablation spots vs 10.1s at PV gap spots, p<0.0001). CF values seem to be higher at successful ablation spot that at PV gap spots (12.5g vs 11.4g, p=0.0592). On the basis of the receiver-operating characteristic curve (ROC) analysis, the best LI drop that predicts successful ablation spots was >20Ω (Sensitivity=56.8%, Specificity=93.2%, PPV=99.7%, Area under the ROC curve=0.7841, p<0.0001). Optimal LI drops were identified by left atrial region and were >21Ω at anterior sites and >18Ω at posterior sites. No steam pops or complications were reported during the procedures. All PVs were successfully isolated in all study patients Conclusions In a large, international population of consecutive de novo AF cases, an ablation strategy guided by LI and CF information results in a very high first pass isolation rate. LI drop is predictive of PV segment isolation. A regional approach to RF ablation guided by LI information may be useful in patients with AF.

Very long term outcomes of atrial fibrillation ablation

Little is known about the very long term durability of atrial fibrillation (AF) ablation. The purpose of this study was to evaluate very long term AF ablation outcomes. We followed 5200 patients undergoing 7145 ablation procedures. We evaluated outcomes after single and multiple ablation procedures for paroxysmal (PAF; 33.6%), persistent (PeAF; 56.4%), and long-standing (LsAF; 9.9%) AF. We compared 3 ablation eras by initial ablation catheter: early (101 patients) using solid big tip (SBT) catheters (October 2003 to December 2005), intermediate (2143 patients) using open irrigated tip (OIT) catheters (December 2005 to August 2016), and contemporary (2956 patients) using contact force (CF) catheters (March 2014 to December 2021). AF freedom at 5, 10, and 15 years was as follows: initial ablation: PAF 67.8%, 56.3%, 47.6%; PeAF 46.6%, 35.6%, 26.5%; and LsAF 30.4%, 18.0%, 3.4%; final ablation: PAF 80.3%, 72.6%, 62.5%; PeAF 60.1%, 50.2%, 42.5%; and LsAF 43.4%, 32.0%, 20.6%. For PAF and PeAF, CF ablation procedures were better than OIT ablation procedures (P < .0001) and both were better than SBT ablation procedures (P < .001). LsAF had no outcome improvement over the eras. The 8-year success rate after final ablation for CF, OIT, and SBT catheter eras was as follows: PAF 79.1%, 71.8%, 60.0%; PeAF 55.9%, 50.7%, 38.0%; and LsAF 42.7%, 36.2%, 31.8%. Highest AF recurrence was in the first 2 years, with a 2- to 15-year recurrence of 2%/yr. Success predictors after initial and final ablation procedures were younger age, smaller left atrium, shorter AF duration, male sex, less persistent AF, lower CHA2DS2-VASc score, fewer drugs failed, and more recent catheter era. After year 2, there is 2%/yr recurrence rate for all AF types. Ablation success is best in the CF catheter era, intermediate in the OIT era, and worst in the SBT era. Over the ablation eras, outcomes improved for PAF and PeAF but not for LsAF. We should follow patients indefinitely after ablation. We need an understanding of how to better ablate more persistent AF.

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.

P5691Independent assessment if an image-processing service for the treatment of patients with ventricular tachycardias

Abstract Background/Introduction Substrate-based radiofrequency ablation (RFA) in combination with pre-procedural computed tomography (CT) or cardiac Magnetic Resonance Imaging (cMRI) emerged as a promising approach to treat ventricular tachycardias (VT). However, image-processing and 3D reconstruction of the relevant structures to embed them into a 3D electroanatomical mapping (EAM) system is time consuming and requires highly experienced personal and a dedicated software. Purpose The aim of the study was to present the first independent experience with a commercially available service of a internet platform in patients referred for RFA of VTs. Methods Seven consecutive patients (pts) with ischemic cardiomyopathy (ICM), non- ischemic cardiomyopathy (NICM) and dilated cardiomyopathy (DCM) referred for VT RFA underwent contrast-enhanced dual-energy CT. The anonymized DICOM dataset was uploaded to the internet platform. After processing by the specialists, the dataset was downloaded and exported in a format compatible with the 3D EAM System. The EAM was performed in sinus rhythm using a 3.5mm open-irrigated tip catheter or a magnetic remote 3.5mm open-irrigated tip catheter in combination with the remote magnetic navigation-system. A multipolar high-density mapping catheter was used in 6 pts. Scar was defined as bipolar voltage &lt;0.5 mV, and scar border zone ≥0.5mV and &lt;1.5 mV. Results of the internet platform-derived wall thinning (WT), scars and the defined substrate based on 3d EAM voltage maps were transferred into a 17-segment model, and the filling of every single segment was rated as 0%, 25%, 50%, 75% and 100%. For analysis, agreement of the filling (percentage) of the individual segments was quantified. Results Mean age was 67±8 year, BMI was 28±5 kg/m2 and 86% were males. File transfers and image processing was feasible in all patients. Agreement between the defined substrate (&lt;0,5mV) and WT of 4mm was very good (≥90%) in 3 pts, good (≥75% &amp; &lt;90%) in one patient, moderate (≥50% &amp; &lt;75%) in one patient and poor (&lt;50%) in one patient. Patient #1 #2 #3 #4 #5 #6 #7 Sex male male male female male male male Age 63y 56y 71y 65y 60y 69y 81y BMI 31kg/m2 32kg/m2 19kg/m2 25kg/m2 28kg/m2 34kg/m2 29kg/m2 LVEF 25% 60% 25% 25% 25% 31% 34% EDVI 123ml/m2 184ml/m2 69ml/m2 114ml/m2 142ml/m2 105ml/m2 75ml/m2 Catheter multipolar high-density + 3.5mm open-irrigated tip 3.5mm open-irrigated tip multipolar high-density + 3.5mm open-irrigated tip multipolar high-density + 3.5mm open-irrigated tip multipolar high-density + magnetic remote 3.5mm open-irrigated tip multipolar high-density + magnetic remote 3.5mm open-irrigated tip multipolar high-density + magnetic remote 3.5mm open-irrigated tip Quality 98% 96% 91% 66% 89% no match 53% Quality = Percentage match between defined substrate and WT. Superimpose – wall thinning and FAM Conclusion(s) Integration of substrate-based segmentation using the service of the internet platform is feasible in daily practice. Agreement between voltage-map based substrate definition and internet platform-based WT was satisfactory in the majority of patients.

Updated results on catheter ablation of ventricular arrhythmias arising from the papillary muscles of the left ventricle.

BackgroundCatheter ablation of ventricular arrhythmias (VAs) arising from the left ventricle`s (LV) papillary muscles (PM) is challenging. In this study we present results of catheter ablation using multiple energy sources and image‐based approaches.MethodsFifty‐three patients (49 ± 17 years old; 34% females; median LV ejection fraction 53 ± 11%) underwent catheter cryoablation or radiofrequency (RF) ablation with non‐contact force sensing (Non‐CFS) catheters and cardiac computed tomography integration (CTII) into the electroanatomical mapping system or contact force sensing RF (CFS RF) ablation catheters and intracardiac echo‐facilitated 3D electroanatomical mapping. Ventricular arrhythmias foci were mapped at either the anterolateral (ALPM) or posteromedial papillary muscles (PMPM). Ablation was performed using an 8‐mm cryoablation catheter (CRYO); a Non‐CFS 4‐mm open‐irrigated RF catheter; or a CFS RF 3.5‐mm open‐irrigated tip catheter, via transmitral or transaortic approach.ResultsAcute success rate was 83% for Non‐CFS RF/CTII; 100% for CRYO/CTII (n = 16) and CFS RF/ICE3D (n = 14) (P = 0.03). Catheter stability was achieved in all patients treated with Cryo/CTII. VA recurrence at 12 months follow‐up was 48% (n = 11) for Non‐CFS RF/CTII; 19% (n = 3) for CRYO/CTII; and 7% (n = 1) for CFS RF/ICE3D (P = 0.02).ConclusionsNon‐CFS/CTII was associated with an increased risk of recurrence of the clinical arrhythmia. Ablation with either CFS RF/ICE3D or CRYO/CTII showed high acute success rates and low recurrence rates during follow‐up. Cryoablation provided stable contact and was less arrhythmogenic.

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.

P390Comparison of 8-mm and open irrigated tip catheters for cavotricuspid isthmus atrial flutter ablation: results from the FLIGHT study

P390Comparison of 8-mm and open irrigated tip catheters for cavotricuspid isthmus atrial flutter ablation: results from the FLIGHT study

Impact of cavotricuspid isthmus morphology in CRYO versus radiofrequency ablation of typical atrial flutter

Objectives. Cryoablation (CRYO) is an alternative to radiofrequency (RF) for catheter ablation of cavotricuspid isthmus (CTI)-dependent atrial flutter (AFL). We aimed to study whether different CTI morphologies had different impacts on procedural success for CRYO and RF. Design. This study randomized 153 patients with CTI-dependent AFL (median age 65 years; range 34–82) to RF or CRYO (78 CRYO; 75 RF). Biplane angiography (RAO 30° and LAO 60°) was done before the ablation procedure and isthmuses were classified as straight (n = 81), concave (n = 43) or pouch-like (n = 29). RF was performed with a 3.5-mm open-irrigated tip catheter and CRYO was performed with a 9 F, 8-mm tip catheter. The ablation endpoint was bidirectional block of CTI. Results. Acute procedural success was achieved in 70/75 patients in the RF group and in 72/78 patients in the CRYO group. With regard to CRYO or RF, acute procedural success rates were similar between the three isthmus types: straight: CRYO (92%) and RF (96%); concave: CRYO (92%) and RF (94%); and pouch-like: CRYO (94%) and RF (85%). There were no significant differences regarding success rate between the different morphologies in the CRYO or the RF group. The CTI was longer in patients with acute failure compared to the patients with acute success (38 ± 7 mm versus 33 ± 6 mm, p = 0.045). Conclusion. The CTI morphology did not influence the acute success rate for either the CRYO or the RF ablation of CTI-dependent AFL. A longer CTI was associated with a lower success rate regardless of energy source.

Proof of concept study: Improvement of echocardiographic parameters after renal sympathetic denervation in CKD refractory hypertensive patients

AimEvaluation of the effectiveness of the renal sympathetic denervation (RSD) in reducing lesions of target organs such as the heart and kidneys, in resistant hypertensive CKD patients. Methods and resultsForty-five patients were included and treated with an ablation catheter with open irrigated tip. RSD was performed by a single operator following the standard technique. Patients included with CKD were on stages 2 (n=22), 3 (n=16), and 4 (n=7). Data were obtained at baseline and monthly until the 6th month of follow-up. Twenty-six out of the 45 patients had LVH and nineteen did not present LVH. The LV mass index decreased from 123.70±38.44g/m2 at baseline to 106.50±31.88g/m2 at the 6th month after RSD, P<0.0001. The end-diastolic left ventricular internal dimension (LVIDd) reduced from 53.02±6.59mm at baseline to 51.11±5.85mm 6months post procedure, P<0.0001. The left ventricular end-diastolic posterior wall thickness (PWTd) showed a reduction from 10.58±1.39mm at baseline to 9.82±1.15mm at the 6th month of follow-up, P<0.0001. The end-diastolic interventricular septum thickness (IVSTd) also decreased from 10.58±1.39mm at baseline to 9.82±1.15mm 6months post procedure, P<0.0001. The left ventricular ejection fraction (LVEF) improved from 58.90±10.48% at baseline to 62.24±10.50% at the 6th month of follow-up, P<0.0001. When the ∆ between baseline and the 6th month post RSD in LVH patients and non LVH patients were compared to the same parameters no significant difference was found. ConclusionsThe RSD seemed to be feasible, effective, and safe resulting in an improvement of echocardiographic parameters in LVH and non LVH CKD refractory hypertensive patients.

Gastroparesis as a Complication of Atrial Fibrillation Ablation

Percutaneous catheter ablation is a safe and effective treatment for symptomatic drug-resistant atrial fibrillation (AF). Gastroparesis is a little known complication of AF ablation. We aimed to evaluate the frequency of gastroparesis in the patients who underwent catheter ablation for AF by cryoballoon (CB) or radiofrequency (RF) and to define risk factors for gastroparesis. In all, 104 patients were treated with pulmonary vein (PV) isolation with 2 different technologies: CB in 58 patients (group 1) and open-irrigated tip RF catheter in 46 patients (group 2). Gastroparesis was seen in 7 cases (6 cases in group 1 and 1 case in group 2, respectively). The complaints related with gastroparesis began during the procedure in 4 of 6 patients of group 1. The other 3 patients admitted to our outpatient clinic with similar complaints within 72 to 96 hours after the procedure. For gastroparesis cases of group 1, mean minimal CB temperature on inferior PVs was lower and left atrium diameter was smaller. Management was conservative, and the patients have no residual symptoms at 6-month follow-up. The only patient still demonstrating residual symptoms during follow-up was in group 2. Although, clinically manifest gastroparesis is quite common with CB ablation, the process is generally reversible. However, damage may not be as reversible with RF ablation. In conclusion, during cryoablation, lower temperatures on inferior PVs and small left atrium size may be associated with increased risk of gastroparesis, and fluoroscopic guidance may be useful to avoid this complication.

Biomarkers of myocardial injury with different energy sources for atrial fibrillation catheter ablation

Our study aims to compare acute myocardial injury biomarker rise after atrial fibrillation ablation performed with different technologies. One hundred and ten patients were treated with pulmonary vein isolation with 4 different technologies: open-irrigated tip radiofrequency (RF) catheter in35 patients (Group A), cryoballoon in 35 patients (Group B), visually guided laser balloon in 20 patients (Group C), open-irrigated tip RF catheter with contact-force-sensing technology in 20 patients (Group D). Post-procedure samples of cardiac troponin I (cTnI) and creatinine kinase-MB (CK-MB) were collected at 19 ± 3 h and 43 ± 3 h after ablation. At the first postprocedural sample, cTnI and CK-MB levels were found elevated in all 110 patients with a median value of 2.11 ng/mL and 8.95 ng/mL, respectively. Group B showed cTnI levels increased (median 5.96 ng/mL) compared to other groups (median Group A: 1.72 ng/mL, Group C: 1.54 ng/mL, Group D: 2.0 ng/mL; p < 0.001). Also CK-MB levels resulted higher in cryoablation (median 26.4 ng/mL) compared to other groups (median Group A: 6.40 ng/mL, Group C: 7.15 ng/mL, Group D: 6.50 ng/mL; p < 0.001). No significant association was observed between biomarker levels and recurrences of atrial fibrillation after a mean follow-up of 369 ± 196 days. Highest markers for myocardial injury were observed in the cryoballoon group. It is possible that a longer delivery energy duration and other factors affecting lesion size resulted in higher amount of cardiac injury in cryoablation. The higher levels of cardiac biomarkers did not translate into a better outcome and its physiologic significance is unknown.

Long‐Term Changes in Heart Rate Variability After Radiofrequency Catheter Ablation for Atrial Fibrillation: 1‐Year Follow‐Up Study with Irrigation Tip Catheter

Radiofrequency catheter ablation (RFCA) for atrial fibrillation (AF) changes cardiac autonomic nerve activity. However, the long-term effect of RFCA has not yet been evaluated when an open irrigation tip catheter (OITC) was used. Therefore, we hypothesized that AF ablation changes heart rate variability (HRV) that would be maintained over 1 year after OITC ablation and be associated with clinical recurrence of AF. We analyzed pre-RFCA HRV (HRVpre ), HRV at 3 months (HRV3mo ) and 1 year (HRV1yr ) after RFCA using 24-hour Holter monitoring after excluding arrhythmic events in 144 patients (70% male, 57 ± 10 years old, 83% paroxysmal AF) who underwent RFCA with OITC. After RFCA with OITC, the increase in mean heart rate and the reduction in HF or LF/HF were significant at HRV3mo (P < 0.001) and were maintained at HRV1yr (P < 0.001). During 20 ± 8 months of follow-up, 33 of 144 patients (23%) showed clinical recurrence of AF. Patients in the nonrecurrence group showed significant reductions of rMSSD and HF at HRV3mo and HRV1yr , but patients with clinical recurrence did not. In Cox regression analysis, a reduction in LF/HF (ΔLF/HF) ≥0.26 at HRV3mo was significantly associated with clinical recurrence of AF (hazard ratio 2.52, 95% CI 1.19-5.32, P = 0.015). In contrast to previous reports about long-term HRV recovery after AF ablation with a conventional catheter, change in cardiac autonomic nervous activity was maintained for 1 year after RFCA when an OITC was used. A reduction in ΔLF/HF ≥0.26 at HRV3mo was independently associated with clinical recurrence of AF after RFCA.

Atrial fibrillation ablation using open-irrigated tip radiofrequency: Experience with intraprocedural activated clotting times ≤210 seconds

Atrial fibrillation (AF) ablation procedures generally use intraprocedural activated clotting time (ACT) of >300-350 seconds to prevent thromboembolic events. To evaluate bleeding and thromboembolic procedural complications in patients with symptomatic AF undergoing ablation procedures with low intraprocedural ACT. We examined a subset of 372 of 2334 (15.9%) AF ablation procedures using open-irrigated tip radiofrequency catheters at 50 W, interrupted oral anticoagulation, and a target ACT of 225 seconds, with average ACT ≤210 seconds. There were 372 ablation procedures in 339 patients with average ACT ≤210 seconds. Patient demographic characteristics were as follows: age 60.9 ± 9.4 years, men 269 (79.3%), left atrial (LA) size 4.27 ± 0.65 cm, prior stroke/transient ischemic attack 24 (7.1%), CHADS2 score 0.94 ± 0.98, and CHA2DS2-VASc score 1.53 ± 1.35. AF type was categorized as paroxysmal in 107 (31.6%), persistent in 200 (59.0%), and long-standing persistent in 32 (9.4%). Procedural and LA times were 119 ± 26 and 82 ± 24 minutes. Patients underwent preprocedure transesophageal echocardiography. The heparin bolus (8738 ± 2823 units, 93.4 mg/kg) was given after LA access, and the maintenance infusion was 1000 units/hour via a single transseptal sheath with subsequent adjustments based on ACT values. The average ACT was 202 ± 7.5 seconds per procedure, with 116 patients with average ACT <200 seconds and 16 patients with all ACTs <200 seconds. Complications occurred in 7 of 372 (1.9%) ablation procedures, including 2 pericardial tamponades (0.54%), 1 groin pseudoaneurysm (0.27%), and 1 pulmonary embolus, several weeks postablation. There were no other bleeding events and no strokes/transient ischemic attacks or systemic thromboemboli. Using open-irrigated tip radiofrequency catheters at 50 W and preablation transesophageal echocardiography as well as infusing maintenance heparin through a single transseptal sheath, AF ablation can be performed safely despite ACT averaging ≤210 seconds. While we are not advocating target ACTs this low, our data suggest that long ACTs may not be absolutely necessary for preventing thromboembolic events. Lower target ACTs may potentially reduce bleeding complications.

Incidences of esophageal injury during esophageal temperature monitoring: a comparative study of a multi-thermocouple temperature probe and a deflectable temperature probe in atrial fibrillation ablation

The study aim was to compare the incidence of esophageal injuries between different temperature probes in the monitoring of esophageal temperature during atrial fibrillation (AF) ablation. One hundred patients with drug-resistant AF were prospectively and randomly assigned into two groups according to the esophageal temperature probe used: the multi-thermocouple probe group (n = 50) and the deflectable temperature probe group (n = 50). Extensive pulmonary vein (PV) isolation was performed with a 3.5-mm open irrigated tip ablation catheter by using a radiofrequency (RF) power of 25-30 W. In both groups, the esophageal temperature thermocouple was placed on the area of the esophagus adjacent to the ablation site. When the esophageal temperature reached 42 °C, the RF energy delivery was stopped. Esophageal endoscopy was performed 1 day after the catheter ablation. No differences existed between the two groups in terms of clinical background and various parameters related to the catheter ablation, including RF delivery time and number of RF deliveries at an esophageal temperature of >42 °C. Esophageal lesions, such as esophagitis and esophageal ulcers, occurred in 10/50 (20 %) and 15/50 (30 %) patients in the multi-thermocouple and deflectable temperature probe groups, respectively (P = 0.25). Most lesions were mild to moderate injuries, and all were cured using conservative treatment. The incidence of esophageal injury was almost equal between the multi-thermocouple temperature probe and the deflectable temperature probe during esophageal temperature monitoring. Most of the esophageal lesions that developed during esophageal temperature monitoring were mild to moderate and reversible.

Catheter-tissue contact force for pulmonary veins isolation: a pilot multicentre study on effect on procedure and fluoroscopy time

AimsCatheter–tissue contact is critical for effective lesion creation in radiofrequency catheter ablation (RFCA). In a multicentre prospective study, we assessed the effect of direct contact force (CF) measurement on acute procedural parameters during RFCA of atrial fibrillation (AF).Methods and resultsA new open-irrigated tip catheter with CF sensing (SmartTouch™, Biosense Webster Inc.) was used. All the patients underwent the first ablation procedure for paroxysmal AF with antral pulmonary vein (PV) isolation, aiming at entry and exit conduction block in all PVs. Ninety-five patients were enroled in nine centres and successfully underwent ablation. Overall procedure time, fluoroscopy time, and ablation time were 138.0 ± 67.0, 14.3 ± 11.2, and 33.8 ± 19.4 min, respectively. The mean CF value during ablation was 12.2 ± 3.9 g. Force time integral (FTI) analysis showed that patients achieving a value below the median of 543.0gs required longer procedural (158.0 ± 74.0 vs. 117.0 ± 52.0 min, P = 0.004) and fluoroscopy (17.5 ± 13.0 vs. 11.0 ± 7.7 min, P = 0.007) times as compared with those in whom FTI was above this value. Patients in whom the mean CF during ablation was >20 g required shorter procedural time (92.0 ± 23.0 vs. 160.0 ± 67.0 min, P = 0.01) as compared with patients in whom this value was <10 g. Four groin haematomas were the only complications observed.ConclusionContact force during RFCA for PV isolation affects procedural parameters, in particular procedural and fluoroscopy times, without increasing complications.

Enhanced Efficiency of a Novel Porous Tip Irrigated RF Ablation Catheter for Pulmonary Vein Isolation

Irrigated tip radiofrequency (RF) catheter ablation is the most frequently used technology for pulmonary vein isolation (PVI). The purpose of this study was to compare the efficiency and the safety of 2 different open irrigated tip RF ablation catheters. A total of 160 patients with symptomatic AF (29% persistent, 68% male, 61 ± 10 years) were randomized to circumferential PVI using 2 different irrigated tip catheters: (1) the novel Thermocool SF(®) with a porous tip (56 holes) or (2) the Thermocool(®) catheter with 6 irrigation holes at the distal tip in both power- and temperature-controlled modes. PVI procedural time and RF duration were significantly shorter with SF(®) versus Thermocool(®) catheter: 104.5 versus 114 minutes (P = 0.023) and 35.4 minutes versus 39.9 minutes (P < 0.001), respectively. Similarly, the total fluoroscopy time and dose were shorter with SF(®) versus. Thermocool(®) catheter: 21 minutes versus 24 minutes (P = 0.02) and 1014.5 μGy*m(2) versus 1377 μGy*m(2) (P < 0.0001), respectively. Irrigation volume was lower with SF(®): 600 mL versus 1100 mL, (P < 0.0001) and the rates of complications were not significantly different (0.6% vs 0.49%, P = 0.66). At 20.5 ± 7.5 months follow-up, there were no significant differences with regard to arrhythmia freedom between SF(®) (59.2%) and TC® groups (59.3%), (P = 0.61). Using the novel irrigated tip SF catheter, PVI is achieved within a shorter ablation and procedural durations. The underlying mechanisms and potential differences in RF lesion size remain to be elucidated.

Ablação da atividade simpática renal com cateter de ponta irrigada: uma opção atraente?

INTRODUCAO: A denervacao simpatica renal por meio de cateteres surgiu como estrategia adjunta para o controle da hipertensao arterial resistente. Nenhum estudo ate o momento comparou os efeitos teciduais de diferentes cateteres, potencias e tempos de aplicacao da radiofrequencia, objetivo do presente estudo. METODOS: Seis arterias renais de porco foram seccionadas em seu eixo longitudinal e colocadas em uma câmara projetada para simular condicoes fisiologicas de fluxo renal. Os cateteres foram posicionados obliquamente a arteria, mantendo-se pressao de contato constante. Aplicacoes de radiofrequencia foram realizadas utilizando-se tres diferentes dispositivos: eletrodo de ponta solida 4 mm/5 F, eletrodo de ponta solida 4 mm/7 F, e eletrodo com ponta aberta irrigada 4 mm/7 F. Duas energias foram aplicadas (8 W e 15 W), durante 30 segundos, 60 segundos e 120 segundos. RESULTADOS: No total foram realizadas 18 aplicacoes. Injuria neural renal mais significativa foi observada utilizando-se cateter 4 mm/5 F e energia de 8 W apenas quando a duracao da aplicacao foi estendida a 120 segundos. Por outro lado, significante dano neural foi observado com o cateter 4 mm/7 F com todas as potencias (8 W e 15 W) e duracoes testadas (30 segundos, 60 segundos e 120 segundos). Lesoes mais profundas foram notadas quando o cateter irrigado foi utilizado, independentemente da potencia e da duracao da aplicacao. CONCLUSOES: O cateter com ponta irrigada produz lesoes mais profundas que os cateteres de ponta solida e seu uso pode ser mais vantajoso na denervacao simpatica renal. A aplicabilidade clinica desses resultados, entretanto, deve ser confirmada.

Safety and Efficacy of Open Irrigated‐Tip Catheter Ablation of Wolff‐Parkinson‐White Syndrome in Children and Adolescents

Irrigated-tip catheter technology has been used for the elimination of resistant accessory pathways (AP) in adults with Wolff-Parkinson-White (WPW) syndrome. However, there are persistent concerns regarding the safety of irrigated catheters in the pediatric population. In this report we present our experience, in terms of effectiveness and safety, of irrigated catheter technology in children and adolescents who underwent ablation of WPW. We prospectively followed up all patients less than 18 years old (n = 41, mean age of 12.8 years old) who were referred to our center for radiofrequency (RF) catheter ablation of WPW between January 2010 and July 2011. Catheter ablation was performed in all patients using an open irrigated-tip catheter (Celsius Thermocool 3.5 mm, 7F, B-type, Biosense Webster, Diamond Bar, CA, USA). Power was started from 15 W up to 30 W in right-sided AP; RF pulses in left-sided APs were delivered at 40 W while 20 W was delivered inside the coronary sinus. Mean procedure time was 26.4 minutes and mean fluoroscopy time was 12.2 minutes. Overall procedural success was obtained in 39/41 (95.1%) patients after the first procedure. No complications were observed after the procedure. All patients attended their scheduled follow-up visit at 3, 6, and 12 months and no recurrences were observed based on 12-lead electrocardiogram and 24-hour Holter monitoring. RF ablation of APs using open irrigated-tip catheters can be performed in children and adolescents with a high acute and long-term success rate, very short procedure times, and acceptable fluoroscopy times.

Renal Sympathetic Ablation Using an Irrigated-Tip Catheter: An Attractive Option?

ABSTRACT Background Catheter-based renal sympathetic denervation has emerged as an adjunct strategy to control refractory hypertension. No studies have yet compared the tissue effects of different catheters, powers and time periods of radiofrequency application, which was the objective of this study. Methods Six porcine renal arteries were sectioned in their longitudinal axis and placed in the flow chamber designed to simulate physiological renal flow conditions. The catheters were placed obliquely to the artery with constant contact pressure. Radiofrequency ablations were performed using three different catheters: 4 mm/5 F solid-tip electrode, 4 mm/7 F solid-tip electrode, and open irrigated-tip 4 mm/7 F electrode. Two different powers were used (8 W and 15 W) for 30, 60 and 120 seconds. Results A total of 18 ablations were performed. More significant nerve damage was observed with the 4 mm/5 F catheter and power of 8 W only when the application duration was extended to 120 seconds. On the other hand, significant nerve damage was observed with the 4 mm/7 F catheter with all power (8 W and 15 W) and duration (30, 60, and 120 seconds) options tested. Deeper lesions were observed with the use of the irrigated catheter, regardless of power and time periods of radiofrequency application. Conclusions The irrigated-tip catheters produce deeper lesions than solid-tip catheters and their use might be more beneficial in treating patients with renal sympathetic denervation. The clinical applicability of these results, however, should be confirmed.

Asymptomatic cerebral lesions during pulmonary vein isolation under uninterrupted oral anticoagulation

Left atrial radiofrequency ablation has been shown to carry a risk of asymptomatic cerebral lesions. No data exist in patients under continued oral anticoagulation during the ablation procedure. The aim of this study was to quantify the amount of silent cerebral lesions assessed by pre-procedural and post-procedural magnetic resonance imaging (MRI) in patients under therapeutic international normalized ratio (INR) and to identify clinical or procedural parameters that correlate with cerebral embolism. A total of 131 consecutive patients undergoing catheter ablation for paroxysmal (n = 80, 61.1%) or persistent (n = 51, 38.9%) atrial fibrillation were included in the study. Pulmonary vein antrum isolation (PVI), roofline, mitral isthmus line, and complex fractionated atrial electrogram (CFAE) ablation using 3.5 mm open-irrigated tip catheters were performed, as needed. All patients underwent pre-procedural and post-procedural cerebral MRI. Post-procedural MRI revealed new embolic lesions in 16 patients (12.2%), all of them asymptomatic. Clinical parameters showing a significant correlation with cerebral embolism in univariate analysis were age (P = 0.027), persistent atrial fibrillation (vs. paroxysmal; P = 0.039), and spontaneous echo contrast in transesophageal echocardiography (P = 0.029). Significant procedural parameters were electric cardioversion (P = 0.041), PVI only (P = 0.008), and ablation of complex atrial electrograms (P = 0.005). Independent risk factors in multivariate analysis were age (P = 0.009), spontaneous echo contrast (P = 0.029) and CFAE ablation (P = 0.006). Radiofrequency ablation in patients under continued oral therapeutic anticoagulation is associated with a substantial risk of silent embolism detected by cerebral MRI. Therefore, continuation of oral anticoagulation is not able to prevent cerebral embolism. A variety of different clinical and procedural factors seem to contribute to the risk of cerebral lesions.