Irrigated Tip Research Articles

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

Contact force sensing in ablation of ventricular arrhythmias using a 56-hole open-irrigation catheter: a propensity-matched analysis

PurposeThe effect of adding contact force (CF) sensing to 56-hole tip irrigation in ventricular arrhythmia (VA) ablation has not been previously studied. We aimed to compare outcomes with and without CF sensing in VA ablation using a 56-hole radiofrequency (RF) catheter.MethodsA total of 164 patients who underwent first-time VA ablation using Thermocool SmartTouch Surround Flow (TC-STSF) catheter (Biosense-Webster, Diamond Bar, CA, USA) were propensity-matched in a 1:1 fashion to 164 patients who had first-time ablation using Thermocool Surround Flow (TC-SF) catheter. Patients were matched for age, gender, cardiac aetiology, ejection fraction and approach. Acute success, complications and long-term follow-up were compared.ResultsThere was no difference between procedures utilising either TC-SF or TC-STSF in acute success (TC-SF: 134/164 (82%), TC-STSF: 141/164 (86%), p = 0.3), complications (TC-SF: 11/164 (6.7%), TC-STSF: 11/164 (6.7%), p = 1.0) or VA-free survival (TC-SF: mean arrhythmia-free survival time = 5.9 years, 95% CI = 5.4–6.4, TC-STSF: mean = 3.2 years, 95% CI = 3–3.5, log-rank p = 0.74). Fluoroscopy time was longer in normal hearts with TC-SF (19 min, IQR: 14–30) than TC-STSF (14 min, IQR: 8–25; p = 0.04).ConclusionBoth TC-SF and TC-STSF catheters are safe and effective in treating VAs. The use of CF sensing catheters did not improve safety or acute and long-term outcomes, but reduced fluoroscopy time in normal heart VA.

Comparison of Contact-force Monitoring Irrigated Tip Catheter and Mesh-like Irrigated Tip Catheter in Atrial Fibrillation Ablation: Prospective Randomized Trial (COMMIC Trial)

Comparison of Contact-force Monitoring Irrigated Tip Catheter and Mesh-like Irrigated Tip Catheter in Atrial Fibrillation Ablation: Prospective Randomized Trial (COMMIC Trial)

Análisis de crecimiento en sorgo forrajero en dos períodos de siembra

Análisis de crecimiento es una cuantificación periódica del rendimiento en materia seca que permite, determinar el momento óptimo de corte. El objetivo fue conocer el crecimiento, para cuantificar la acumulación de materia seca en un intervalo de tiempo, en cuatro variedades de sorgo forrajero: Caña dulce, Silo miel, Esmeralda y Fortuna, similarmente, determinar fenología, en dos períodos de siembra: punta de riego (abril-octubre) y lluvias (junio-diciembre) en Montecillo, Texcoco, Estado de México. Se determinó fenología, altura de planta (AP), número de hojas (NDH), número de tallos (NDT), número de nudos por planta (NDP), rendimiento de materia seca (RMS), se calculó índice de área foliar (IAF), duración de área foliar (DAF), tasa de crecimiento del cultivo (TCC) y tasa de asimilación neta (TAN). El diseño experimental bloques completos al azar con arreglo factorial y cuatro repeticiones, variables significativas, se compararon con prueba de Tukey (p≤ 0.05). Caña dulce presentó mayor AP (210 cm) en ambos períodos, a 145 días después de la siembra(dds) promedio; NDT (33), NDH (8.1), NDN (8.3); TCC (24 g m-2 d-1 a 75(dds) y 26 g m-2 d-1 a 84 dds), TAN (19.1 g m-2 d-1 y 13.8 g m-2 d-1 desde emergencia a 20 dds); lo anterior, resultó en mayores rendimientos (p≤ 0.05) por metro cuadrado (15.7 y 15.5 t Ms ha-1) en punta de riego y período de lluvias, respectivamente. El cultivar Silo miel presentó mayor IAF con 5 a 125 dds y 4.6 a 120 dds y DAF de 114 días; lo anterior, para punta de riego y lluvias, respectivamente. El mejor cultivar para la región fue Caña dulce.

Larger and deeper ventricular lesions using a novel expandable spherical monopolar irrigated radiofrequency ablation catheter.

Radiofrequency (RF) ablation is an established treatment for ventricular tachycardia (VT). However, the inability of current RF catheters to address deep or large substrate may explain most of the clinical failures. The aim of this study is to assess the efficacy and safety of ablation in the left ventricle (LV) in sheep using a novel 8-Fr deflectable ablation catheter (Sphere-9; Affera, Inc) with a 9-mm expandable spherical monopolar irrigated RF tip vs a standard RF irrigated catheter (Biosense Webster, Diamond Bar, CA). The impact on tissue was assessed on local bipolar electrograms (from nine uniformly distributed mini surface electrodes and an internal central reference electrode), as well as on direct lesion measurement post mortem. Eleven sheep underwent LV endocardial ablation in healthy tissue using the Sphere-9 catheter (n = 6), or a conventional irrigated RF catheter (n = 5). Twenty lesions were created with the Sphere-9 (current limit: 2.7 A; temp. limit: 60°C; irrigation: 30 mL/min; and duration: 60-120 seconds). Local bipolar electrograms at the surface of the catheter disappeared during RF delivery in 17 of 20 (85%) lesions. The mean lesion volume was 1707 ± 771 mm 3 (length: 15.8 ± 3.3 mm; width: 11.6 ± 4.2 mm; and depth: 10.3 ± 2.9 mm). Twenty-five lesions were created with a standard RF irrigated catheter (power control 35 W; irrigation: 30 mL/min; duration: 60 seconds; volume 537 ± 398 mm 3 ; length: 8.2 ± 2.3 mm; width: 5.2 ± 1.8 mm; and depth: 5.5 ± 2.4 mm). The novel spherical RF catheter created significantly larger lesions ( P < .001 for measurements in all dimensions). There were no steam pops with the novel ablation catheter vs one with the conventional catheter. This novel spherical monopolar irrigated RF catheter creates lesions that are twice as large and deep as a standard irrigated RF catheter.

Porous tip contact force-sensing catheters for pulmonary vein isolation: performance in a clinical routine setting.

In catheter ablation of atrial fibrillation (AF), contact force (CF)-sensing catheters with an irrigated tip are used to deliver radiofrequency (RF) energy to the tissue. The ThermoCool® Smarttouch™ Surroundflow catheter (STSF) integrates CF-sensing technology and a new porous tip for advanced external cooling. The aim was to evaluate the performance and safety of STSF in a clinical setting of pulmonary vein isolation (PVI) in comparison with standard contact force-sensing catheter (ST). We assigned consecutive patients (n = 80, prospectively, open-label, non-randomized) with symptomatic AF to either PVI with STSF (n = 60) or ST (n = 20). Total ablation time to achieve PVI was significantly shorter in STSF compared to that in ST (STSF, 1556 ± 435s vs. ST, 1922 ± 961s; p = 0.045). Ablation time to achieve loss of pace capture of left pulmonary veins was shorter using STSF (left veins, 155 ± 140s vs. 291 ± 188s; p = 0.01; right veins, 208 ± 196s vs. 369 ± 306s; p = 0.09). Furthermore, administered irrigation fluid was significantly reduced in STSF (241.4 ± 79.6ml vs. 540.3 ± 229.5ml; p < 0.01). CF was lower during ablation of left pulmonary veins. One steam pop occurred in STSF, which did not lead to pericardial effusion (vs. no steam pop in ST). The Kaplan-Meier estimate 12-month AF recurrence was 34.3% and 37.7% (p = 0.8). Integrating CF technology and the porous tip technology enables effective energy transfer to the tissue resulting in shorter ablation time and less irrigation fluid administration. In our cohort, PVI using the STSF was not associated with an increased complication rate or AF recurrence rate after 12-month follow-up when compared with the ST.

Usefulness of Electroanatomical Mapping with Contact Force Monitoring for Accessory Pathways Ablation in Pediatric Population.

The current approach for catheter ablation (CA) of accessory pathways (AP) includes the use of standard catheters under fluoroscopic visualization. We hypothesize that use of contact force (CF) irrigated tip catheters might increase procedural safety in pediatric patients compared to standard irrigated tip catheters, by decreasing the number of radiofrequency (RF) pulses required to obtain AP elimination. Seventy-one pediatric patients (13.7 ± 2.5years, 45 male) with ventricular pre-excitation were enrolled in the study. CA was performed with a standard irrigated tip catheter up to June 2013 in 41 patients (Group S) and with a CF sensing irrigated tip catheter later on in 30 patients (Group CF). In the Group CF, RF was applied with a minimal CF of 5g; CF > 35g was avoided. Group CF procedures required less fluoroscopy (6.8 ± 4.8min), compared to Group S (12.2 ± 10.8min, p = 0.007). The number of RF pulses was smaller in Group CF compared to Group S (2.5 ± 2.0 vs 5.5 ± 1.9, p < 0.01). The mean CF during the effective RF pulse was 18 ± 7.7g, force-time integral was 1040.7 ± 955.9gs, Ablation Index was 513.0 ± 214.2. The procedure was acutely successful in 70 patients; at 12months follow-up 2 patients had AP recurrence, one for each group. No major complications were reported. The use of CF irrigated tip catheters was associated with a smaller number of RF pulses and less fluoroscopy, as compared to mapping and ablation with standard irrigated tip catheters.

Evaluation of Postoperative Pain after Irrigation Using End Vented NaviTip Tips Versus Side Vented NaviTip Tips in Teeth with Irreversible Pulpitis: A Randomized Clinical Trial

objectives: This clinical study was conducted to evaluate and compare the post-operative pain after the using of two different irrigation tips: end-vented NaviTip tip and double sideport NaviTip irrigator tip immediate postoperatively and 4, 12, 24 ,48, 72 hours and 7 days utilizing a numerical rating scale (NRS). Methods: 38 patients with vital lower posterior teeth without periapical radiolucency underwent one-visit root canal treatment, Root canals were prepared using NiTi ProTaper Universal rotary system then randomized into two equal gropus according to the needle used for irrigation group(A) NaviTip® 29-gauge 27 mm with End vented Tip and Group (B) NaviTip® 31-gauge 27 mm with Side vented Irrigator Tip. The needles of irrigation were penetrated 2 mm shorter than the working length. The trial design of this study is a Parallel randomized controlled trial. All demographic data, clinical and radiographic findings and modified VAS scores obtained from patients were statistically analyzed. Results: showed that there was no statistically difference between the two groups regarding the demographic data, prevalence of pre-operative pain, after 4 hours, 12 hours, 24 hours, 48 hours and 7 days. There is no statistical significance difference between End vented NaviTip and Side vented NaviTip , while in both groups there was a statistically significant decrease in pain intensity preoperatively compared with all other time periods.Conclusion: there was a statistically significant decrease in pain intensity preoperatively compared with all other time periods

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.

Remaining challenges in catheter ablation of accessory pathways: rare entity of coronary sinus diverticulum-associated pathways.

A limited number of case reports of coronary sinus (CS) diverticula complicating catheter ablation have been published. We retrospectively analysed 2245 patients who underwent ablation of an accessory pathway (AP) at our institution between 1/11/1993 and 31/10/2016. Eight patients (0.36%) were found to have a CS diverticulum in venography. APs showed a mean antegrade conduction time of 276 ± 23ms (range 220-310ms) and a mean retrograde conduction of 301 ± 45ms (230-350ms). Four patients had 1 (n = 2), 2 (n = 1), or 3 (n = 1) previously failed ablation attempts. Pathways could not be ablated with a conventional 4mm tip catheter in 7 of 8 cases. In seven patients, ablation was successful, in two using an 8-mm ablation catheter, in two using cryoablation, and in the remaining three with an irrigated tip ablation catheter. After failed femoral approach, one 9-year-old female was successfully ablated via the right jugular vein. In one 75-year-old female, ablation was not successful. During a mean follow-up of 8.9 ± 6.4 years, all patients remained free of recurrences. In inferoseptal pathways, especially with previous failed ablation attempts, venographies of the CS should be performed. After successful ablation long-term prognosis is excellent.

The best of two worlds? Pulmonary vein isolation using a novel radiofrequency ablation catheter incorporating contact force sensing technology and 56-hole porous tip irrigation.

This study aimed to evaluate feasibility and safety as well as 1-year clinical outcome of pulmonary vein isolation (PVI) using a unique radiofrequency ablation catheter ("Thermocool SmartTouch SurroundFlow"; STSF) incorporating both, contact force (CF) sensing technology and enhanced tip irrigation with 56 holes, in one device. A total of 110 patients suffering from drug-refractory atrial fibrillation underwent wide area circumferential PVI using either the STSF ablation catheter (75 consecutive patients, study group) or a CF catheter with conventional tip irrigation ("Thermocool SmartTouch", 35 consecutive patients, control group). For each ablation lesion, a target CF of ≥ 10-39g and a force time integral (FTI) of > 400 gs was targeted. Acute PVI was achieved in all patients with target CF obtained in > 85% of ablation points when using either device. Mean procedure time (131.3 ± 33.7min in the study group vs. 133.0 ± 42.0min in the control group; p = 0.99), mean fluoroscopy time (14.0 ± 6 vs. 13.5 ± 6.6min; p = 0.56) and total ablation time were not significantly different (1751.0 ± 394.0 vs. 1604.6 ± 287.8s; p = 0.2). However, there was a marked reduction in total irrigation fluid delivery by 51.7% (265.52 ± 64.4 vs. 539.6 ± 118.2ml; p < 0.01). The Kaplan-Meier estimate 12-month arrhythmia-free survival after the index procedure following a 3-month blanking period was 79.9% (95% CI 70.4%, 90.4%) for the study group and 66.7% for the control group (95% CI 50.2%, 88.5%). This finding did not reach statistical significance (p = 0.18). Major complications occurred in 2/75 patients (2.7%; one pericardial tamponade and one transient ischemic attack) in the study group and no patient in the control group (p = 18). PVI using the STSF catheter is safe and effective and results in beneficial 1-year clinical outcome. The improved tip irrigation leads to a significant reduction in procedural fluid burden.

Preventing the risk of coronary injury in posteroseptal accessory pathway ablation in children: different strategies and advantages of fluoroscopy integrated 3D-mapping system (CARTO-UNIVU™).

To evaluate various strategies in order to minimize the risk of coronary injury during posteroseptal accessory pathways ablation in children. We retrospectively reviewed 68 posteroseptal accessory pathways ablation procedures (20 decremental and 48 typical accessory pathways) performed in 62 pediatric patients at our institution between July 2009 and December 2016. Only posteroseptal accessory pathways targeted near or within the coronary sinus were included and ablation was mostly performed using irrigated tip radiofrequency. Median patient age was 11years with a median body weight of 39kg. Thirty patients underwent a coronary angiogram, 21 were coupled to the 3D navigation system CARTO-UNIVU™. The coronary angiogram showed a distance of less than 5mm between the coronary artery and the ablation site in 40% of our cases; 3 patients had a coronary injury related to RF ablation, 6 patients were switched for cryoablation, 3 patients received limited RF energy (20W). There were no demographic data predicting the proximity of the coronary artery to the ablation site. Ablation of posteroseptal accessory pathways specifically in children carries a risk of coronary artery injury which is probably underestimated. The use of merged 3D images and coronary angiograms, the reduction of RF energy or the switch to cryoablation are possible alternatives to limit the risk of coronary injury.

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

1160Early experience with ablation index-guided pulmonary vein isolation compared with force-time integral-guided ablation using surround flow catheter tip irrigation for ablation of atrial fibrillation

1160Early experience with ablation index-guided pulmonary vein isolation compared with force-time integral-guided ablation using surround flow catheter tip irrigation for ablation of atrial fibrillation

How to Approach Difficult Cases of AVNRT.

Our approach to the ablation of atrioventricular nodal reciprocating tachycardia (AVNRT), the most common supraventricular tachycardia, is as follows: We first attempt ablation in the right atrial posteroseptum anterior to the coronary sinus ostium with a 4-mm non-irrigated tip catheter. If ablation within the triangle of Koch is unsuccessful with radiofrequency (RF), we switch to cryoablation and target a more superior (mid septal) region. We also utilize cryoablation if RF ablation produces transient VA block (absence of retrograde conduction during junctional rhythm) or a fast junctional rhythm (<350msec). If cryoablation were to fail, or is not available, we would then suggest ablation within the coronary sinus targeting the roof (2-4cm from the os) using a 3.5-mm irrigated tip catheter. If tachycardia were still inducible despite these measures, we would then proceed with transseptal puncture (given our greater experience with this over a retrograde aortic approach) and perform RF ablation along the posteroseptal left atrium and inferoseptal mitral annulus utilizing an irrigated tip catheter. In our experience, cryoablation reliably results in elimination of the slow pathway. The only left atrial ablation for AVNRT at our institution in the past year was performed because a patent foramen ovale allowed for rapid left atrial access, facilitating left atrial ablation of the slow pathway.

Endodontic management of a maxillary lateral incisor with an unusual root dilaceration diagnosed with cone beam computed tomography

Anterior teeth may have aberrant anatomical variations in the roots and root canals. Root dilaceration is an anomaly characterized by the displacement of the root of a tooth from its normal alignment with the crown which may be a consequence of injury during tooth development. This report aims to present a successful root canal treatment of a maxillary lateral incisor with unusual palatal root dilaceration (diagnosed with cone beam computed tomography) in which the access cavity was prepared from the labial aspect of the tooth to provide a straight line access to the root canal system which was instrumented using OneShape rotary file system and precurved K-files up to size 50 under copious irrigation of 2.5% NaOCl using a side-vented irrigation tip. The canal was then obturated using the warm vertical compaction technique.

Radiofrequency Ablation of Atrial Fibrillation: Nonrandomized Comparison of Circular versus Point-by-Point "Smart" Ablation for Achieving Circumferential Pulmonary Vein Isolation and Curing Arrhythmic Symptoms.

Pulmonary vein isolation (PVI) with radiofrequency (RF) ablation is now standard care for atrial fibrillation (AF). New improvements in PVI techniques include use of catheters that measure contact-force and circular ablation catheters. These techniques have not been compared. We compared the success rate of circumferential pulmonary vein isolation (CPVI) with: (1) "point by point" RF using an irrigated tip ablation catheter with "smart touch" contact-force; (2) irrigated nMARQ circular ablation catheter in 86 patients with AF. The endpoints of the study were acute and long-term success rate of CPVI. The 2 groups had similar characteristics: Smart Touch group with 50 patients, age 62 ± 8 years, 64% male; nMARQ group with 36 patients, 75% male, age 58.7 ± 10 years. The type of AF was similar in the 2 groups: paroxysmal and persistent in 68% and 32% in the Navistar group versus 64% and 36% in the nMARQ group. Follow-up periods were similar (18.4 months vs. 19 months, P = 0.59). All the pulmonary veins were successfully isolated in both groups. However, PVI could not be achieved with the nMARQ in 2.7% of the pulmonary veins ablated and was completed with a Smart Touch. The long-term success rate was comparable in the 2 groups. The nMARQ and Smart Touch catheters give similar results in PVI of both paroxysmal and persistent AF. The procedural time was shorter with the nMARQ in paroxysmal AF. Need for crossover from nMARQ to Smart Touch occurred in 2.7% of PVs ablated.

A Novel Endoscopic Catheter for "Laparoscopy-Like" Irrigation and Suction: Its Research and Development Process and Clinical Evaluation.

Inspired by natural orifice translumenal endoscopic surgery (NOTES), the authors launched a development of novel endoscopic irrigation and suction (I/S) catheter for "laparoscopy-like" I/S in flexible gastrointestinal (GI) endoscopy. The aims were to describe its basic research and development (R&D) process and to estimate its performance in both preclinical and clinical settings. In basic R&D phase, a layout of side hole at apex nozzle of endoscopic I/S (EIS) catheter were theoretically calculated and designed. Material of nozzle was selected based on the strength analysis. The performance of final prototype EIS catheter was then assessed preclinically in the porcine stomach, to compare with conventional endoscopic "tip irrigation" and "tip suction" as control. After regulatory clearance, safety and feasibility of I/S using EIS catheter were clinically assessed by endoscopists in small number of patients. Bench tests revealed 0.4 mm in diameter, 24 holes, and 6-8 holes per circumference as most suitable layout of side holes, and polyetheretherketone as an optimal nozzle material, respectively. Time to inject 500 mL saline with the EIS catheter was significantly shorter than tip irrigation (101 ± 3.1 seconds versus 154 ± 3.1 seconds; P < .05). The EIS suction was significantly weaker than conventional endoscopic tip suction, though it remained within the practical range. No mucosal injuries were noted in the EIS suction. In clinical assessments for human use, no adverse events were observed, and high degree of satisfaction for endoscopists was obtained. The newly developed EIS catheter is safely used with satisfactory performance in flexible GI endoscopy.

Spatial distribution of electrical reconnection after pulmonary vein isolation in patients with recurrent paroxysmal atrial fibrillation.

IntroductionRecurrence of atrial fibrillation after pulmonary vein isolation (PVI) occurs frequently and may be associated with electrical reconnection of the pulmonary veins (PV). We investigated spatial distribution of electrical reconnection during re-do procedures in patients with paroxysmal atrial fibrillation who had previous successful acute electrical PVI with either single irrigated tip, antral ablation (s-RF; n = 38) or multi-electrode, duty-cycled ablation (PVAC; n = 48).Methods and ResultsEP navigator, mapping and irrigated tip ablation catheters were used in all re-do procedures. Sites of reconnection were assessed in a 12-segment model. Baseline clinical and demographic characteristics were similar in both groups. The number of PVs reconnected per patient was similar in both groups (2.9 ± 0.9 and 3.2 ± 0.7 (p = 0.193), s‑RF and PVAC, respectively), and each PV was equally affected. However, the inferior quadrant of the right lower PV was significantly more vulnerable to reconnection after previous PVAC ablation, whereas the superior quadrant of the right upper PV showed significantly more reconnection in the s‑RF group.ConclusionThe overall number of PVs reconnected was equally high in both groups, and each PV was affected equally. However, there were significant differences in the spatial distribution of electrical reconnection. Better understanding of predilection sites for reconnection might help to improve the long-term success rate of PVI.

Apical Extrusion of Debris and Irrigants Using Different Irrigation Needles.

This study evaluated the influence of irrigation tip, root canal curvature and final apical diameter on periapical debris and irrigant extrusion during root canal instrumentation. After being classified as mildly or moderately curved, the mesiobuccal root canals of 90 human molars were instrumented. The teeth were allocated into three groups according to the used needle type: a flat open-end needle (Group 1), a side-vented needle (Group 2) or a double side-vented needle (Group 3). The amount of extruded material after instrumentation was calculated for each group. The differences in irrigant and debris extrusion between the experimental groups were analyzed with the Mann-Whitney U test. Irrigation tips and final instrument diameter differences were analyzed with the Kruskal-Wallis test. Multiple groups were compared using the Mann-Whitney U-test with a Bonferroni correction at α=0.05. The amount of extruded material from the double side-vented needle was significantly less than the open-ended flat needle (p=0.008), but there was no difference compared to the side-vented needle (p=0.929). The results showed no effect of root curvature and final apical diameter on the amount of irrigant and debris extrusion (p>0.05). The double side-vented needles generated the least material extrusion to the periapical tissues. Irrigation needle type had the greatest influence on periapical irrigant and debris extrusion and the double side-vented needles may be safely used during endodontic therapy.