Study on safety of radiofrequency catheter ablation in treatment of AV nodal reentrant tachycardia / 医学研究生学报

Objective:To investigate the couse of 24 cases AVB during RFCA and 5 cases after RFCA in total 94 AVNRT patients. Methods:94 AVNRT patients received RFCA in which time, the energy and power were gradually discussed. The correlation among AVB and both different anatomical positions (upper, middle and lower zone) and A/V, H-value in intraventricular ablation mapping were studied respectively. Results: With the elevation of ablation zone, the AVB risk was also increased. The intraventricular ablation mapping showed that:①Increase of A/V and H-value means higher AVB risk;② Simultaneous increase of A/V and H-value would lead to the most dangerous result. Conclusion:It is of great importance to perform RFCA under such situation:middle and lower zone as ablation positions multiple-peak A wave, A/V(0.1-0.25) and no H or slightest H(≤0.02?0.03)mV are present in intraventricular ablation mapping, which could significantly lower the risk of RFCA-related AVB.

Predictors of successful catheter ablation of AV nodal reentrant tachycardia / 대한내과학회지

Catheter ablation of the AV nodal slow pathway using radiofrequency (RF) energy has been established as the first-line curative therapeutic modality of recurrent symptomatic AV nodal reentrant tachycardia (AVNRT). In contrast to catheter ablation of the AV bypass tract, there was no useful marker to localize succesful site of the pathway. This study was performed to determine predictors of successful catheter ablation of the AV nodal slow pathway in patients with AVNRT. METHODS: Forty patients (18 men, 22 women; 47.9+/-13.3 years) with AVNRT undergoing successful catheter ablation of the AV nodal slow pathway were included in this study, in which 217 attempts were tried to ablate the AV nodal slow pathway. Characteristics of local atrial electrogram, anatomical site at each attempt, junctional rhythm during RF delivery were analyzed (40 successful, 177 failed). Maximum difference and duration of atrial electrograms were measured and local atrial electrograms were classified into 5 types (A1, A2, B1, B2 and C type) according to the type and the degree of fragmentation. Finally, the occurrence of junctional rhythm during RF discharge and its onset time were compared between successful and failed attempts. RESULTS: There was no significant difference in the maximum difference of amplitude and duration of atrial electrograms between successful and failed attempts. The success rate in each type of atrial electrogram was significantly different. And, the success rate in non-C type atrial electrograms (A1, A2, B1, and B2) was significantly higher than that in type C atrial electrograms (25.0% vs 10.3%, p<0.01). No significant difference was noted in success rates according to attempted sites. Junctional rhythms during radiofrequency application occured significantly more frequent in successful attempts than in failed attempts (87.5% vs 47.5%, p<0.001). The time to onset of junctional rhythm was not different between successful and failed attempts (5.2+/-4.9 sec vs 6.1+/-5.5 sec). CONCLUSION: Fragmented local atrial electrogram and junctional rhythm during RF energy delivery may be used to predict successful catheter ablation of AVNRT. It is recommended that RF energy should be applied to the site where fragmented atrial electrogram is recorded and terminated if junctional rhythm does not develop within 15 seconds after starting RF energy delivery.

Predictors of successful catheter ablation of AV nodal reentrant tachycardia / 대한내과학회지

Catheter ablation of the AV nodal slow pathway using radiofrequency (RF) energy has been established as the first-line curative therapeutic modality of recurrent symptomatic AV nodal reentrant tachycardia (AVNRT). In contrast to catheter ablation of the AV bypass tract, there was no useful marker to localize succesful site of the pathway. This study was performed to determine predictors of successful catheter ablation of the AV nodal slow pathway in patients with AVNRT. METHODS: Forty patients (18 men, 22 women; 47.9+/-13.3 years) with AVNRT undergoing successful catheter ablation of the AV nodal slow pathway were included in this study, in which 217 attempts were tried to ablate the AV nodal slow pathway. Characteristics of local atrial electrogram, anatomical site at each attempt, junctional rhythm during RF delivery were analyzed (40 successful, 177 failed). Maximum difference and duration of atrial electrograms were measured and local atrial electrograms were classified into 5 types (A1, A2, B1, B2 and C type) according to the type and the degree of fragmentation. Finally, the occurrence of junctional rhythm during RF discharge and its onset time were compared between successful and failed attempts. RESULTS: There was no significant difference in the maximum difference of amplitude and duration of atrial electrograms between successful and failed attempts. The success rate in each type of atrial electrogram was significantly different. And, the success rate in non-C type atrial electrograms (A1, A2, B1, and B2) was significantly higher than that in type C atrial electrograms (25.0% vs 10.3%, p<0.01). No significant difference was noted in success rates according to attempted sites. Junctional rhythms during radiofrequency application occured significantly more frequent in successful attempts than in failed attempts (87.5% vs 47.5%, p<0.001). The time to onset of junctional rhythm was not different between successful and failed attempts (5.2+/-4.9 sec vs 6.1+/-5.5 sec). CONCLUSION: Fragmented local atrial electrogram and junctional rhythm during RF energy delivery may be used to predict successful catheter ablation of AVNRT. It is recommended that RF energy should be applied to the site where fragmented atrial electrogram is recorded and terminated if junctional rhythm does not develop within 15 seconds after starting RF energy delivery.

Anatomical Sites of the Successful Catheter Ablation Using the Anatomic Approach in Patients with AV Nodal Reentrant Tachycardia

BACKGROUND AND OBJECTIVES: Intracardiac electrocardiographic finding using as a guide for selective catheter ablation in patients with AV nodal reentrant tachycardia (AVNRT) is not specific. Therefore, we evaluated the efficacy and safety of the anatomical approach for catheter ablation in patients with AVNRT. MATERIALS AND METHOD: Among the patients diagnosed as AVNRT by electrophysiologic study, total 66 patients (M:F=26:40) were included in this study. In the right anterior oblique radiographic view, the septal annulus of tricuspid valve, extending from the most posterior region of the annulus adjacent to coronary sinus ostium (posterior) to His bundle recording site (anterior), was divided into posterior (P), mid (M), and anterior (A) sites. Radiofrequency (RF) energies were applied from the posterior part to the anterior part sequentially along the septal annulus of tricuspid valve until successful ablation. RESULTS: Successful anatomical sites were located in posterior (11 patients), mid (48 patients), and anterior (7 patients) sites. The most patients (62 patients) were treated with slow pathway ablation except 4 patients in whom fast pathway was ablated. Probable slow potentials were observed in 8 patients (12%, 3 in posterior sites and 5 in mid sites). Transient complete AV block followed by first degree AV block and delayed complete AV block was occured in one case whose ablation site was A1. And another 3 patients had postablation first degree AV block. CONCLUSION: In patients with AVNRT, the ablated pathway were different according to successful anatomical site. And RF catheter ablation of atrioventricular nodal reentrant circuit guided by anatomical landmark is safe and efficacious.

The Selective Radiofrequency Catheter Ablation in Patients with AV Nodal Reentrant Tachycardia

BACKGROUND: The catheter ablation using radiofrequency(RF) energy in patients with AV nodal reentrant tachycardia(AVNRT) has been proved as a safe and effective nonpharmacologic therapeutic modality. The selective ablation of slow pathway is now becomming a standard treatment in patients with AVNRT because of its high success rate and negligible AV block risk. In our study, we demonstrated the feasibility, success rate and complications of selective radiofrequency catheter ablation of fast pathway or slow pathway for the treatment of AV nodal reentrant tachycardia. METHODS: Among patients diagnosed as AVNRT by electrophysiologic study, total 21 patients (M : F=11 :10, mean age ; 39 years old) were included in this study. Selective RF ablation of fast pathway was performed in 9 patients and selective RF ablation of slow pathway in 12 patients. The RF generator used in this study was Osypka HAT 200 model and catheters were 6F or 7F steerable catheters with 4 mm distal tip. RESULTS: The successful selective abation was achieved in 18 of 21 patient(86%). The success rate of selective ablation of fast pathway was 67%(6/9 patients) and that of slow pathway was 100%(12/12). The complication(complete AV block) was occurred in one patient in slective ablation of fast pathway but there was no AV block in selective ablation of slow pathway. During follow-up, there was one recurrence in patients treated by selective ablation of fast pathway(mean F/U : 17 months) but there has been no recurrence yet in patients treated by selective ablation of slow pathway(mean F/U : 6 months). The procedural feasibility between two ablation methods in terms of total procedure time, fluoroscopic time and number of RF applications was not differrent significantly. CONCLUSION: The RF ablation in patients with AV nodal reentrant tachycardia is a safe and a effective nonpharmacologic therapeutic modality. Especially, the selective RF ablation of slow pathway is a promising therapeutic modality in patients with AV nodal reentrant tachy cardia.

AV Nodal Reentrant Tachycardia with 2:1 AV Block

BACKGROUND: Second degree AV block is occasionally induced during AV nodal reentrant tachycardia by programmed electrical stimulation. This study was performed to determine the incidence, the block site, and the mechanism of AV block during AV nodal reentrant tachycardia. METHODS AND RESULTS: The study population was 67 consecutive patients with AV nodal reentrant tachycardia studied by programmed electrical stimulation. Among these patients, common types(slow pathway for anterograde and fast pathway for retrograde conduction) were 64 patients and uncommon types(fast pathway for anterograde and slow pathway for retrograde conduction) were 3 patients. Among 67 patients with AV nodal reentrant tachycardia 10 patients developed 2:1 AV block during tachycardia. The block site of AV block was infrai bundle in 9 patients and supraHis bundle in patient. There were intermittent aberrancies of RBBB and/or LBBB form during tachycardia in 5 patients with infraHis AV block. CONCLUSION: The occurrence of AV block during AV nodal reentrant tachycardia is not rare and might be related to the prematurity of atrial extrastimulation. The block sites of AV block were infraHis bundle in most cases and this finding suggests that distal common pathway of the reentry circuit is present in the AV node.