Radiofrequency Ablation Of Slow Pathway Research Articles

Atrioventricular nodal reentry tachycardia treatment using CARTO 3 V7 activation mapping: a new era of slow pathway radiofrequency ablation is under coming.

Slow pathway (SP) ablation is the cornerstone for atrioventricular nodal reentry tachycardia (AVNRT) treatment, and a low-voltage bridge offers a good target during mapping using low x-ray exposure. We aimed to assess a new tool to identify SP by activation mapping using the last CARTO3® version, i.e., CARTO PRIME® V7 (Biosense Webster, Diamond Bar, CA, USA). Right atrial septum and triangle of Koch 3D-activation map were obtained from intracardiac contact mapping during low x-ray CARTO 3® procedure. In 60 patients (mean age 60.3 ± 14.7, 61% females) undergoing ablation for AVNRT, an automatic activation map using a DECANAV® mapping catheter and CARTO® Confidense™, Coherent, and FAM DX software modules were obtained. The SP was identified in all patients as the latest atrioventricular node activation area; RF catheter ablation (RFCA) in that region elicited junctional beats. The mean procedural time was 150.3 ± 48.3 min, the mean fluoroscopy time exposure was 2.9 ± 2 min, the mean dose-area product (DAP) was 16.5 ± 2.7 cGy/cm2. The mean number of RF applications was 3.9 ± 2, the mean ablation index was 428.6 ± 96.6, and the mean contact force was 8 ± 2.8 g. There were no adverse event during the procedure, and no AVNRT recurrences occurred during a mean follow-up of 14.3 ± 8.3 months. Ablation of the SP by automatic mapping using Confidense™, Coherent, and FAM DX software modules is an innovative, safe, and effective approach to AVNRT ablation. The CARTO3® V7 system shows on a 3D map the latest AV node activation area during sinus rhythm allowing low fluoroscopy time and highly effective RFCA.

Slow pathway elimination using antegrade conduction improvement with fast atrial pacing during AVNRT radiofrequency ablation: a proof-of-concept study

Background Radiofrequency (RF) ablation of slow pathway (SP) is usually performed in sinus rhythm while monitoring the occurrence of a slow junctional rhythm (JR). JR although sensitive, is not specific for elimination of SP conduction. Our objective was to prospectively evaluate feasibility and safety of SP elimination using fast atrial rate pacing (FAP) during RF delivery. Methods Consecutive patients admitted for atrioventricular nodal re-rentrant tachycardia (AVNRT) ablation were included. The rate of proximal coronary sinus (CS) pacing was set to a value constantly yielding antegrade SP conduction, while carefully monitoring the AH interval. RF delivery (at the lower part of Koch’s triangle) was considered successful if the AH shortened ≥ 14 ms or if transition from Wenckebach (WK) periods to a 1:1 conduction occurred. Results 24 patients were included (54 ± 20 y). Typical AVNRT was induced in all (cycle length 349 ± 83 ms). RF delivery during CS pacing (335 ± 73 ms) led to AH shortening by 51 ± 25 ms in 13 patients. In 10 patients, a transition from 3:2 or 4:3 WK periods to 1:1 conduction occurred during the successful pulse. In one patient, atrial fibrillation was systematically induced during FAP, requiring conventional ablation. Non-inducibility, and SP conduction disappearance was obtained in all patients. No patient developed AV block. After a follow-up of 12 ± 3 months, no recurrences were observed. Conclusion SP ablation using FAP during RF delivery allows direct visualisation of its disappearance. In our cohort of patients, this technique was feasible without safety compromise.

Delayed reversible atypical type I second degree atrio-ventricular block in a patient undergone slow pathway radiofrequency ablation: A case report and a short review of the literature.

Delayed reversible atypical type I second degree atrio-ventricular block in a patient undergone slow pathway radiofrequency ablation: A case report and a short review of the literature.

Inadequate, inappropriate sinus-node tachycardia. An old cardiac arrhythmia in a new perspective

Introduction: The inadequate, inappropriate sinus-node tachycardia is not a rare clinical syndrome, defined as a non-paroxysmal, increased sinus-rate at rest, and/or inadequate response to physical and/or emotional stress, and palpitations. Aim: The aim of this study was to describe our experiences with the investigations of our inappropriate sinus-node tachycardia patients. Method: In the last years, 104 patients (92 women, 12 men, mean age: 31 ± 10 years) were treated with this cardiac arrhythmia entity. All patients underwent 12 leads ECG, chest X-ray, echocardiography, Holter-monitoring and transtelephonic ECG observations. The quality of life score was estimated by using the European Heart Rhythm Association scale. Results: Patients had no structural heart disease (physical examination ECG, chest X-ray, echocardiography were normal), the laboratory values (TSH, blood count) were within normal limits, but the resting heart rates were repeatedly high (102 ± 8/min). The results of Holter recording (expressed as minimal-maximal [average] heart rate/min) without drug therapy showed high heart rate values (59 ± 8, 160 ± 14 [94 ± 6]/min). The standard bicycle ergometry showed an average loading capacity of 124 ± 23 watt (heart rate: control: 99 ± 12/min, top: 167 ± 13/min) with early, inadequate sinus tachycardia. To disclose the episodes of paroxysmal supraventricular tachycardia, beside the Holter-monitoring transtelephonic ECG system was used. This diagnostic modality was very useful for the exclusion of paroxysmal supraventricular tachycardia episodes during the palpitation symptoms. Out of 104 patients, 4 patients (3.8%) showed familiar occurrence, another 16 patients (15.2%) had previous slow-pathway radiofrequency ablation due to atrioventricular nodal reentry tachycardia. Conclusions: Based on our clinical observations, it can be pointed out that inappropriate sinus-node tachycardia syndrome (1) occurs mainly in young women, mostly in students, inducing decreased quality of life scores (EHRA score: 2.3 ± 0.4); (2) the prevalence in our outpatient clinic was 0.7%; (3) the patient population is not homogeneous: familiar or postablation occurrence is possible in some patients; (4) transtelephonic ECG has been proved to be very useful to disclose episodes of paroxysmal supraventricular tachycardia in these patients. Orv Hetil. 2019; 160(37): 1464-1470.

073_16823-L2 Compared the Efficacy of Cryoablation and Rradiofrequency Ablation for Treatment of Atrioventricular Nodal Reentrant Tachycardia

Radiofrequency (RF) ablation of the atrioventricular nodal slow pathway is the accepted treatment for atrioventricular nodal reentrant tachycardia (AVNRT), with success rates greater than 90%. The major risk is atrioventricular nodal block requiring permanent pacemaker implantation. Cryoablation is

Atrioventricular nodal echoes over a wide echo window as a therapeutic end point for the catheter-guided radiofrequency ablation of atrioventricular nodal reentrant tachycardia: a prospective study.

In previous retrospective studies, it was shown that the presence of residual single atrioventricular node (AVN) echoes with an echo zone longer than 30 ms may increase the rate of recurrence after radiofrequency ablation (RFA) of slow pathway in patients with AVN reentrant tachycardia (AVNRT). Based on that, some centres perform additional RFA in these patients. However, this opinion has never been tested prospectively and many centres do not perform re-ablation in these patients. The purpose of this study was to test whether persistence of a single AVN echo over a wide echo zone is a valid end point for RFA. In this prospective study, 576 patients who had a non-inducible arrhythmia post-RFA of AVNRT were divided into those with a remnant echo over a wide echo zone (case group) and those reaching classical end points (control group). The primary end point of the study was recurrence and patients were followed for 34.5 ± 18.8 months. In the control group (n = 510), 14 patients (2.7%) had a recurrence while no recurrence was seen in the case group (n = 66) (final cure rate, 97.3 vs. 100%; difference, 2.7%; upper bound of the 98% CI, 0.0488; P < 0.0001 for non-inferiority). Two complete heart blocks (0.4%) happened in the control group and none in the case group (P = 0.784). Non-inducibility in the presence of a wide echo window is non-inferior to non-inducibility in the presence of narrow echo window or no AVN echoes. In general, the presence of a single echo beat is not an indication for further ablation and this applies for both narrow and wide windows.

Slow Pathway Radiofrequency Ablation Using Magnetic Navigation: A Description of Technique and Retrospective Case Analysis

The Magnetic Navigation System (MNS) catheter was shown to be stable in the presence of significant cardiac wall motion and delivered more effective lesions compared to manual control. This stability could potentially make AV junctional re-entrant tachycardia (AVNRT) ablation safer. The aim of this study is to describe the method of mapping and ablation of AVNRT with MNS and 3-D electro-anatomical mapping system (CARTO, Biosense Webster, Diamond bar, CA, USA) anatomical mapping, with a view to improve the safety of ablation. The method of precise mapping and ablation with MNS is described. Consecutive AVNRT cases (n=30) from 2012 January to 2015 November, in which magnetic navigation was used, are analysed. Ablation was successful in 27 (90%) out of 30 patients. In three cases, ablation was abandoned due to the proximity of the three-dimensional His image to the potential ablation site. No complications, including AV nodal injury, occurred. The distance from the nearest His position to successful ablation site in both LAO and RAO projections of CARTO images was 26.4±8.8 and 27±7.7mm respectively. Only in two (9%) patients, ablation needed to be extended superior to the plane of coronary sinus ostium, towards the His bundle region, to achieve slow pathway modification. AVNRT ablation with MNS allows for accurate mapping of the AV node and stable ablation at a safe distance, which could help avoid AV nodal injury. We recommend this modality for younger patients with AVNRT.

0040: Score for arrhythmias detection in symptomatic patients after AV node re-entrant tachycardia ablation

Slow pathway radiofrequency ablation is used to treat atrioventricular nodal re-entrant tachycardia (AVNRT), but some patients remain symptomatic. The aim of study was to find predictive clinical factors of arrhythmias recurrence in symptomatic patients after AVNRT ablation and risk factors of AF occurrence. Slow pathway ablation was performed in 929 patients with AVNRT and aged 52±18 years. RF energy, 65°, 40 watts was delivered, until AVNRT was not induced. 94 patients were excluded because ablation failed. During follow-up (mean 2.2±2 years), 136 (16%) had recurrence of symptoms. After invasive and non-invasive studies, symptoms were related to a sinus tachycardia (n=39) (5%)(group I), a tachycardia of other origin (atrial fibrillation (AF) (n=54)(6%) (group II) or AVNRT recurrence (n=43) (5%) (group III); 699 patients were asymptomatic (84%) (group IV). Group II was older (60±12 years) than group III (51±20), I (33±15.5), IV (52±18)(p<0.001), less frequently female (48%) than group I (85%), III (63%), IV (66%)(p<0.001) and had more frequently history of AF (30%) than group I (3%), III (0%) and IV (3%). Other factors as induction after isoproterenol, mechanism of AVNRT, history of syncope, number of RF applications, were not different at univariate and multivariate analysis. A score ≥3 based on age and history of AF (1 for age 45-60 years, 2 for age >60, 3 for history of AF) identified all symptomatic patients with AF. A score 0 excluded patients with AF-related symptoms. Patients with only sinus tachycardia and recurrent AVNRT can not be differentiated except by a younger age, in case of sinus tachycardia. Recurrence of symptoms after successful AVNRT ablation is relatively frequent (16%), but recurrence of AVNRT is only present in 5% of patients. A score ≥3 based on age and history of AF identified all patients at risk of AF. Careful management is required in these patients.

Recovery of absence seizure-like symptoms in a patient after slow pathway radiofrequency ablation

Epileptic seizures result from electrical hypersynchronization of neuronal networks in the cerebral cortex and characterized by recurrent epileptic seizures due to a genetically determined or acquired brain disorder [1]. Nonepileptic seizures are sudden changes in behavior that resemble epileptic seizures but are not associated with the typical neurophysiological changes that characterize epileptic seizures [2]. Absence seizures or complex partial seizures can be difficult to distinguish from nonepileptic seizure or events when using only the patient's history or by observation [3].

Recurrences of symptoms after AV node re-entrant tachycardia ablation: A clinical arrhythmia risk score to assess putative underlying cause

Purpose of the researchTo identify clinical factors associated with the probability for each arrhythmic mechanism causing recurring symptoms after atrioventricular nodal re-entrant tachycardia (AVNRT) ablation. Slow pathway radiofrequency ablation is used to treat AVNRT. After ablation, recurrence of symptoms due to AVNRT or other arrhythmias can occur. ResultsWe studied 835 patients successfully treated with AVNRT ablation. Variables associated with each specific arrhythmia underlying symptom recurrence were studied by logistic regression.During a mean follow-up of 2.2±2years, 136 (16%) patients had a recurrence of symptoms. Following invasive and non-invasive studies, symptoms were mostly attributed to sinus tachycardia, recurrence of AVNRT and atrial arrhythmias (respectively 4.7%, 5.2% and 6.1%). Older age and history of atrial fibrillation were associated with a markedly increased risk of symptom recurrence due to atrial arrhythmias (OR=15.58, 7.09–35.22, p<0.001) whereas younger age was associated with a higher risk of sinus tachycardia. A simple 3-item clinical score based on age categories and atrial fibrillation history efficiently predicted atrial arrhythmia (C-Index=0.82, 0.75–0.89) and sinus tachycardia (C-Index=0.83, 0.75–0.90). 8.3% of patients with scores=0 had atrial arrhythmias whereas 100% of patients with scores ≥4 had atrial arrhythmias. ConclusionsWhile recurrence of symptoms after successful AVNRT ablation is relatively frequent (16%), true AVNRT recurrence accounts for only 1/3 of these recurrences. A simple clinical score based on age and history of atrial fibrillation enables efficient risk stratification for symptom recurrence attributable to atrial arrhythmias and inappropriate sinus tachycardia.

AGE AND GENDER-RELATED SYMPTOMS RECURRENCE AFTER AV NODE RE-ENTRANT TACHYCARDIA

Slow pathway radiofrequency (RF) ablation currently is used to treat patients with atrioventricular nodal re-entrant tachycardia (AVNRT). The aim of study was to evaluate the factors explaining the recurrence of symptoms after AVNRT ablation. 881 patients 291 males, 590 females, mean age 52±18

Atrioventricular nodal reentrant tachycardia ablation with radiofrequency energy during ongoing tachycardia: is it feasible?

IntroductionRadiofrequency (RF) ablation of the slow pathway for treatment of atrioventricular nodal reentrant tachycardia (AVNRT) is conventionally performed during sinus rhythm.AimTo evaluate the clinical and electrophysiological features and the short- and long-term results of slow pathway RF ablation during ongoing AVNRT.Material and methodsA total of 282 consecutive patients with AVNRT undergoing RF catheter ablation were analysed. Patients whose tachycardia episodes could not be controlled during RF energy application and who underwent slow pathway ablation or modification during ongoing tachycardia formed the study group (group 1, n = 16) and those ablated during sinus rhythm formed the control group (group 2, n = 266).ResultsOf the clinical characteristics, only the frequency of tachycardia attacks was higher in group 1 (3.3 ±1.2 vs. 2.1 ±0.9 attacks/month, p < 0.001). Among the baseline electrophysiological measurements, the echo zone lasted significantly longer in group 1 than in group 2 (78 ±25 ms vs. 47 ±18 ms; p < 0.001). The immediate procedural success rate was 100% in both groups. There were no significant differences between groups regarding the mean number of radiofrequency energy applications (5.2 ±4.2 vs. 5.8 ±3.9), total procedure times (42.4 ±30.5 min vs. 40.2 ±29.4 min) and fluoroscopy times (11.4 ±8.5 min vs. 12.2 ±9.3 min) (p > 0.050 for all). All patients were followed-up for 29 ±7 months; only 2 patients (< 1%) in group 2 recurred (p > 0.050). No permanent atrioventricular block was observed.ConclusionsThe RF catheter ablation or modification of the slow pathway during ongoing AVNRT is feasible with acceptable short- and long-term efficacy and safety. However, this approach needs to be clarified with large-scale studies.

Ablation of slow pathway in a patient with persistent left superior vena cava

We describe a case of successful radiofrequency ablation of slow pathway in a 54 year-old woman with persistent left superior vena cava. The ablation was performed using anatomical approach, outside the ostium of coronary sinus.

Recovery of atrioventricular block with teophylline and methylprednisolone occurring few days after slow pathway radiofrequency ablation

Recovery of atrioventricular block with teophylline and methylprednisolone occurring few days after slow pathway radiofrequency ablation

Long-term results of slow pathway ablation in patients with atrioventricular nodal reentrant tachycardia: simple approach

AimsThe aim of this study was to report the short- and long-term results of slow pathway radiofrequency (RF) ablation in patients with atrioventricular (AV) nodal reentrant tachycardia (AVNRT) using a simplified approach (2 catheters and short applications of RF). Materials and MethodsThis was a retrospective study that included consecutive patients with AVNRT. We used an anatomical approach with only 2 catheters. Decremental AV nodal conduction and atrial-His conduction interval jump were measured. To detect the onset of the QRS, we used surface lead II. During the stimulation protocol, we performed S2-QRS and S3-QRS measurements. An increase in the S3-QRS3 interval of 50 milliseconds or greater in response to a decrease in the S2-QRS2 coupling interval of 10 milliseconds was defined as a discontinuous AV nodal function curve and taken as evidence of dual antegrade AV pathways. Atrioventricular nodal reentrant tachycardia was demonstrated by the presence of dual AV nodal physiology, atrial echoes, and tachycardia induction with a 1:1 AV relationship and a VA interval of less than 70 milliseconds. Short RF applications (10-15 seconds) were delivered at an intermediate point between the posteroseptal and medioseptal regions of the Koch triangle. The applications were considered effective when junctional rhythm appeared. The end point was the demonstration of slow pathway modification without AVNRT induction. ResultsThree hundred forty-four patients (age, 49.22 ± 17.47 years; 254 were female) were included. Discontinuous AV nodal function curves were found in 271 patients (78.77%), and short-term success was achieved in all patients. The anterograde jump in AV nodal conduction was abolished after RF in 222 patients (81.91%), and discontinuous AV nodal conduction and single AV nodal echo beats persisted in 49 cases (18%). The mean number of RF application was 7.79 ± 2.23, the mean number of effective applications was 4.63 ± 0.62, and the mean RF application time was 54.92 ± 8.03 seconds. The total procedure and fluoroscopy time was 29.45 ± 9.6 and 10.87 ± 2.36 minutes, respectively. After the procedure, all patients were followed up for a mean of 46.44 ± 18.89 months, and 7 patients (2%) presented AVNRT recurrences. Complications were observed in 4 patients (1.16%); no permanent AV block was observed. ConclusionIn this study, slow pathway RF ablation using a simplified approach technique is an effective and safe approach for the treatment of AVNRT.

Heart Rate Variability and Atria Function in Children at Late Follow-Up Evaluation After Atrioventricular Node Slow-Pathway Radiofrequency Ablation

This study was designed to assess the changes in the conductive system, autonomic dysfunction, and global and regional function of the atria and ventricles in children late after slow-pathway radiofrequency ablation (RFA). The study enrolled 22 children, who has successfully undergone RFA 2 to 5 years previously (RFA group) and 20 healthy children (control group). Electrophysiologic study was performed for the RFA group. Holter monitoring and echocardiography were performed for all the children. At a late follow-up assessment, the RFA children were free of paroxysms, whereas 8 of the 22 children (36%) reported transient palpitations. Both mean and maximal heart rates (HR) were significantly increased, whereas indices of HR variability (% of succesive normal sinus RR intervals exceeding 50 ms [pNN50], root mean square of the succesive normal sinus RR interval difference [rMSSD], high-frequency component [HFC]) were significantly decreased in the RFA group compared with preablation and control data. Left atrial (LA) and right atrial (RA) volumes were significantly higher, and atria deformation indices were significantly lower in the RFA group. Correlations were found between the mean HR and the volumes of LA (r = 0.477; p < 0.001) and RA (r = 0.512; p < 0.001). A negative correlation between the maximal LA volume and the longitudinal strain rate (SR) during relaxation (r = –0.476; p = 0.03) and a positive correlation between the minimal LA volume and both longitudinal SR (r = 0.361; p = 0.03) and strain (ε) (r = 0.375; p = 0.024) during contraction were shown. These data suggest a possible link between atrial dysfunction and the hyperadrenergic state after RFA.

Speckle tracking derived left and right ventricular strain, strain rate and

Objectives: Aim of the study was to assess left and right ventricular strain, strain rate and left ventricular rotation in children at late follow-up after atrioventricular node slow pathway radiofrequency ablation. Materials and methods: Left and right ventricular strain, strain rate, left ventricular rotation, rotational ve-locity and twist were assessed using the speckle tracking echocardiography in 22 children who underwent radiofrequency ablation of slow pathway and in 15 healthy control children. Results: There were no significant differences in conventional echocardiographic left and right ventricular parameters between the two groups (p>0.05), except left atrial volume (28.0±8.7 ml in control group vs. 37.3±13.9 ml in radiofrequency ablation group, p=0.024) and right atrial volume (16.0±6.7 ml vs. 21.5±8.5 ml, respectively, p=0.047) and their left (16.7±6.0 ml/m2 vs. 26.3± 9.8 ml/m2, p=0.002, respectively) and right (16.0± 6.6 ml/m2 vs. 21.5±8.5 ml/m2, respectively, p=0.05) indices that were significantly higher in radiofrequency ablation group. Speckle tracking imaging derived regional and global strain, systolic and diastolic left and right ventricular strain rate as well as left ventricular rotation, rotational rate did not differ between the radiofrequency ablation group and controls (p>0.05). Left ventricular twist was comparable between the radiofrequency ablation group and controls (p>0.05). Conclusions: Speckle tracking echocardiography did not revealed any deterioration of regional and global long and short axis function of the left and right ventricles in children, who underwent atrioventricu-lar node slow pathway radiofrequency ablation.

Which parameters describe the electrophysiological properties of successful slow pathway RF ablation in patients with common atrioventricular nodal reentrant tachycardia?

Atrioventricular nodal reentrant tachycardia (AVNRT) accounts for about 60% of the patients presenting with paroxysmal supraventricular tachycardia. The radiofrequency (RF) catheter ablation of the slow atrioventricular (AV) node pathway is the preferred therapeutic approach in patients with AV node reentrant tachycardia. The aim of our study was describe the electrophysiological properties of successful slow pathway RF ablation in patients with common atrioventricular nodal reentrant tachycardia. The study design was a retrospective analysis involving fifty consecutive patients (18 males; mean age of 39+/-22 years) who underwent slow pathway ablation because of AVNRT. Slow junctional beats with a cycle length longer than 550 ms were observed in 39 patients (79%); the presence of rapid junctional beats with a cycle length less than 550 ms was showed in 5 patients (10%). Moreover, in 32 of 50 patients (65%) duration of atrial electrogram more than 40 ms was noticed. Analyzing data reported, we found the statistically significant presence of slow junctional beats (p=0.001) and atrial electrogram >40 ms (p=0.05) in successful RF ablation procedures. In patients with AVNRT undergoing slow pathway ablation, the duration of atrial electrogram >40 ms and slow junctional beats with cycle length >550 ms during the application of RF energy describe the electrophysiological properties of successful slow pathway RF ablation.

Slow Pathway Radiofrequency Ablation in Patients with AVNRT: Junctional Rhythm is Less Frequent during Magnetic Navigation Ablation Than with the Conventional Technique

The occurrence of accelerated junctional rhythm (JR) during radiofrequency ablation of the slow pathway in patients with atrioventricular nodal reentrant tachycardia (AVNRT) is frequent. The aim of the present study was to compare the occurrence of JR during magnetic remote catheter ablation to the conventional manual ablation. Twenty six patients (males: seven; age: 51 + or - 15 years) underwent slow pathway ablation with magnetic navigation (MN) system (Niobe, Stereotaxis Inc., St. Louis, MO, USA) and were compared to a control group of 11 patients (males: three; age: 53 + or - 16 years) treated with conventional manual ablation. A 4-mm nonirrigated tip catheter was used in both groups with a maximum of 30 W and 60 degrees C. Acute success was obtained in all patients. In the MN group, three patients out of 24 had no junctional beat (JB) at all and seven patients had 10 or less JB. In contrast, in the conventional group no patient had less than 10 JB. The mean number of JB in the MN group was 66 + or - 94.9 (0-410) and 200 + or - 243.1 (43-914) in the control group (P = 0.019). In the MN group one patient had a first-degree atrioventricular block. No other complication occurred. Magnetic remote catheter ablation of AVNRT is effective and is associated with less JB than the manual conventional technique. Therefore, JB may not be considered as a mandatory indicator for successful AVNRT ablation with MN system.

Can successful radiofrequency ablation of atrioventricular nodal reentrant tachycardia be predicted by pattern of junctional ectopy?

Background Emergence of junctional rhythm (JR) during radiofrequency (RF) current delivery directed at the periatrioventricular nodal region has been shown to be a marker of success in atrioventricular nodal reentrant tachycardia (AVNRT). Whereas the characteristics of JR during RF ablation of slow pathway have already been studied, the electrophysiologic features of different patterns of JR are yet to be evaluated. The aim of this study was to investigate in detail the characteristics of the JR that develops during the RF ablation of the slow pathway. Materials and Results The study population consisted of 95 patients: 56 women and 33 men (mean age, 47.2 ± 16.3 years) who underwent slow pathway ablation because of AVNRT. A combined anatomical and electrogram mapping approach was used, and AVNRT was successfully eliminated in all patients. This study identified 7 patterns for JR during the RF ablation of slow pathway: junction-junction-junction, sinus-junction-sinus, intermittent burst, sparse, no junction, sinus-junction-junction, and sinus-junction-block . The characteristics of JR, such as mean cycle length and total number, were gathered. The incidence of JR was significantly higher during effective applications of RF energy than during ineffective applications ( P = .001). The mean number of junctional ectopy was 19.6 ± 19. The total number of junctional ectopy was significantly higher during effective applications of RF energy than during ineffective applications (24.6 ± 18.8 vs 8.4 ± 13.2; P < .001). We found a significant difference between the effective and ineffective applications of RF energy in the mean cycle length of the junctional ectopy (464.6 ± 167.5 vs 263.4 ± 250.2; P < .01). The patterns of JR were compared between effective and ineffective applications. We managed to show a significant correlation between patterns of JR and successful ablation ( P = .01). Logistic regression analysis revealed that the presence of sinus-junction-sinus, sinus-junction-junction, and sinus-junction-block patterns of JR was a predictor of a successful RF ablation (confidence interval [CI], 1.67-15.92 [ P < .004]; CI, 1.02-85.62 [ P = .048]; and CI, 1.06-32.02 [ P = .042], respectively). Conclusion This study confirms that JR is often present during successful slow pathway ablation. The pattern of JR is useful as indicator of success.