Radiofrequency Catheter Ablation of Three Accessory Pathways in a Single Session

Radiofrequency Ablation of Multiple Accessory Pathways. A 19-year-old patient is described having three accessory atrioventricular pathways. All three pathways were ablated using radiofrequency current in a single electrophysiologic investigation. (J Cardiovasc Electrophysiol, Vol. 3, pp. 141–149, April 1992)     

Patterns of radiofrequency catheter ablation of left free-wall accessory pathways: Implications for accessory pathway anatomy

Despite the abundance of literature on the electrophysiology of accessory pathways, clinical data on their anatomic properties remain infrequent. The small and discrete nature of lesions generated by radiofrequency (RF) energy may allow better characterization of accessory pathway anatomy in the intact heart. RF catheter ablation was performed on 40 left free-wall accessory pathways in 39 consecutive patients with a unipolar endocardial approach. The patterns of accessory pathway ablation were identified. Spatial-electrophysiologic information provided by the ablation catheter at individual sites of RF application and corresponding data from the coronary sinus catheter were correlated with the effects of RF energy on accessory pathway conduction. Of 39 accessory pathways permanently (n = 37) or transiently (n = 2) ablated, 24 had “simple” ablation, with abolition of conduction by one individual RF application. In 15 of 24 pathways that could be crossed by the coronary sinus catheter, the concordance in anatomic and electrophysiologic information between the site of earliest retrograde atrial activation and the effective ablation position (ventricular approach) suggested a perpendicular fiber course. Fifteen pathways had “complex” ablations; of these, eight had spatial-electrophysiologic discordance between the atrial and ventricular insertions, suggesting an oblique fiber orientation. Seven pathways had modification or transient suppression of conduction, with or without subsequent abolition of conduction at identical or physically disparate (1 cm apart) sites; four pathways had sequential ablation of antegrade and retrograde conduction. These raised possibilities of broad fiber span and functional longitudinal dissociation of accessory pathway conduction. Accessory pathways with simple and complex ablations did not differ in clinical and electrophysiologic parameters. Complex ablations demanded more lengthy and difficult procedures. In conclusion, 38% of left free-wall accessory pathways in this series had complex patterns of RF ablation. The results of this study raised interesting implications in regard to accessory pathway anatomy and provided information that might facilitate electrophysiologic guidance of RF accessory pathway ablation.     

Ablation of right-sided accessory pathways with atrial insertion far from the tricuspid annulus using an electroanatomical mapping system

Ablating Right‐Sided Accessory Pathways With Atrial Insertions Far From Tricuspid Annulus . Background: It is difficult to ablate a right‐sided accessory pathway (AP) with atrial insertion far from the tricuspid annulus (TA). We report our initial experience of ablating this rare AP by a 3‐dimensional electroanatomical mapping system (CARTO). Methods: From January of 2006 to April of 2008, 18 patients with right‐sided APs who failed previous outside ablations were enrolled in this study. Retrograde AP conduction was mapped during pacing at the right ventricular apex by activation‐mapping the right atrium (RA) using a 3‐dimensional electroanatomical mapping system. AP atrial insertion was defined as the earliest retrograde atrial activations and successful ablation of the APs at this site. Results: Among the 18 patients who had failed previous ablation, 10 patients (7 patients with right manifest APs and 3 patients with right conceal APs) had atrial insertions far from the TA. Of the 10 patients, the atrial insertions were found at the base of the RA appendage in 3 patients, at the high lateral RA in 5 patients, at the low lateral RA in other 2 patients. Ablation at the atrial insertions successfully abolished the AP conduction. The mean distance between the atrial insertion sites and the TA was 20.2 ± 2.7 mm. No patients reported recovered AP conduction or recurrent tachycardias after 6‐month follow‐up. Conclusions: The right‐sided APs may have atrial insertion far from the TA. These uncommon variation of APs can be reliably identified and ablated using CARTO system. (J Cardiovasc Electrophysiol, Vol. 22, pp. 499‐505 May 2011)     

Usefulness of paced activation sequence mapping in catheter ablation of accessory pathways

INTRODUCTION: Radiofrequency (RF) ablation of accessory pathways (APs) is often a time-consuming procedure, mainly because conventional criteria have modest accuracy. Thus, additional mapping criteria are desirable. Our hypothesis was that comparison of paced atrial activation sequences with that obtained during orthodromic AV reentrant tachycardia might be useful for locating the atrial insertion of single APs. METHODS AND RESULTS: The study included 15 patients with a single AP referred for ablation. Analysis of the atrial activation sequence was simplified by measuring the activation time (AT) that elapsed between two atrial reference points placed next to the AV annulus on either side of the area containing the AP. Ablation was guided by conventional criteria. Before each RF delivery, a short pacing train was delivered from the ablation catheter and, after verification of atrial capture, the AT was compared with the AT obtained during orthodromic tachycardia. Fifty sites of RF delivery were appropriate for analysis. The multivariate model with the highest predictive power included a deviation of AT between pacing and tachycardia < or = 5 msec (P < 0.001), a local AV ratio > or = 1 (P = 0.04), and stability of the local electrogram (P = 0.05). The combination of all these criteria predicted a successful application with high sensitivity, specificity, and positive predictive value (92%, 86%, and 71% respectively). To validate the method prospectively, 10 additional consecutive patients underwent an AP ablation procedure guided by these criteria. CONCLUSION: This technique seems to be highly accurate in selecting the atrial site for RF ablation of single APs.     

Radiofrequency ablation of multiple accessory pathways.

The aim of the study was to review the clinical and electrophysiological characteristics and results of radiofrequency catheter ablation in patients with multiple accessory pathways to compare them with those of patients with single accessory pathways. Electrophysiological study and radiofrequency catheter ablation were performed in 1010 consecutive cases with Wolff Parkinson White Syndrome. Presence of multiple accessory pathways was documented in 31 patients (3.1%); 30 had two, and 1 had three accessory pathways. Of the 63 accessory pathways, 42 were manifest and 21 concealed. Nine patients had Ebstein's anomaly associated with atrioventricular bypass tracts. The most common combination was right posteroseptal with right free wall bypass tracts (15 patients with 30 accessory pathways). Fifty-one of the sixty-three accessory pathways (81%) were ablated successfully without complications. The duration of the procedure was 100 +/- 58 min and the fluoroscopic time 40 +/- 17 min. A follow up of 5 +/- 3 years after ablation, demonstrated recurrences of six accessory pathways (9.5%). In conclusion, patients with multiple accessory pathways can be treated by radiofrequency ablation in only one session with a high success rate although slightly less than that in patients with a single accessory pathway (81% vs 93%, P<0.01).     

Temperature-controlled radiofrequency catheter ablation of manifest accessory pathways

OBJECTIVES: The primary objectives of this study were to assess the feasibilityof temperature-controlled radiofrequency catheter ablation ofleft and right sided manifest accessory pathways in patientswith Wolff-Parkinson-White syndrome and to gain more insightsinto biophysical aspects of temperature-controlled catheterablation in humans. BACKGROUND: The electrode-tissue interface temperature and other biophysicalparameters are among important variables determining the efficacyand safety of radiofrequency ablation of accessory pathways.Experimental studies have shown that radiofrequency-inducedtissue necrosis can be accurately predicted by monitoring ofcatheter tip temperature. METHODS: 38 consecutive patients (14 f, 24 m; aged 42 ± 12 years)with anterograde conducting accessory pathways (left sided:n=22; right sided: n=l6) underwent temperature-controlled radiofrequencyablation (HAT 200S, Dr Osypka, Germany). The electrode temperaturewas monitored via a thermistor embedded into a 4 mm cathetertip. Power output was adjusted automatically during energy deliveryin a closed loop system (preselected temp.: 70·1 ±5·8°C). RESULTS: Accessory pathway conduction was successfully abolished in allpatients after the delivery of 2·3 ± 2·1radiofrequency pulses (range: 1–9, median: 2). Interruptionof the accessory pathway as evidenced by loss of preexcita tionoccurred after 5·9 ± 5·4 s. At the timeof the interruption of the accessory pathway the catheter tiptemperature measured 54·2 ± 11· 2 °C in patients with left and 44·9 ± 5·0°C in patients with right sided accessory pathways, respectively(P<0·008). Higher temperature levels during left sidedapplications did not shorten the time it took for the effectto appear (left sided accessory pathway: 7· 5 ±6· 3 s, right sided accessory pathway: 3· 7 ±2· 9 s; ns). The catheter tip temperature was significantlyhigher during left compared to right sided applications after5 (52· 1 ± 3· 1 °C vs 47· 2± 4· 3 ° C) and 10s (61· 5 ±6· 2 ° C vs 52· 7 ± 4· 2°C) following initiation of the impulse (P<0· 005).Power output and delivered energy did not differ significantlyat the time of accessory pathway abolition. Peak values of deliveredpower (45· 1 ± 10· 9 W vs 41· 3± 10· 6W; P< 0· 05) and total deliveredenergy (2452 ± 1335 J vs 1392 ± 762 J; P<0·02) were significantly higher in the group of right sided pathwayscompared to left sided applications. The peak temperature measured77· 1 ± 13 °C during effec tive and 69·9 ± 14 °C during ineffective energy applications(P<0· 05). The time it took for the effect to appearwas significantly longer in transiently effective pulses (10·4 ± 7· 2 s) compared to permanently effectiveapplications (5· 9 ± 5· 4 s; P<0·02). Despite temperature control, an abrupt rise in impedancewas observed in 10 of 89 (11%) energy applications. No procedure-relatedcomplications occurred. CONCLUSIONS: Temperature-controlled radiofrequency ablation of manifest accessorypathways is highly effective and safe. The temperature responseis faster and signficantly higher in left-sided energy applicationscompared to right-sided pulses. Peak temperature levels measuredat the electrode tip are significantly higher during effectivethan ineffective pulses. Sudden rises in impedance are not completely prevented during temperature-controlled radiofrequencyablation of accessory pathway, although no procedure-relatedcomplications were noted in this patient cohort. (Eur Heart J 1996; 17: 445–452)     

射频消蚀房室旁道时阻抗监测的意义

分析７４例房室旁道（ＡＰ）射频消蚀术（ＲＦＣＡ）中阻抗（Ｉｍ）监测情况。成功放电时Ｉｍ值为１０８．８±２０．９Ω，有效放电为１１１．０±１３．９Ω，无效放电为１１３．３±２４．７Ω。三种放电状态下Ｉｍ值无显著差异。不同性别及放电部位间Ｉｍ亦无显著差异。结果提示ＲＦＣＡ中Ｉｍ值的理想范围为８０～１４０Ω。     

Development and Validation of an ECG Algorithm for Identifying Accessory Pathway Ablation Site in Wolff-Parkinson-White Syndrome

ECG Localization of Accessory AV Pathways. Introduction : Delta wave morphology correlates with the site of ventricular insertion of accessory AV pathways. Because lesions due to radiofrequency (RF) current are small and well defined, it may allow precise localization of accessory pathways. The purpose of this study was to use RF catheter ablation to develop an ECG algorithm to predict accessory pathway location.
Methods and Results : An algorithm was developed by correlating a resting 12-lead ECG with the successful RF ablation site in 135 consecutive patients with a single, anterogradely conducting accessory pathway (Retrospective phase). This algorithm was subsequently tested prospectively in 121 consecutive patients (Prospective phase). The ECG findings included the initial 20 msec of the delta wave in leads I, II, aVF, and V₁ [classified as positive (+), negative (-), or isoelectric (±)] and the ratio of R and S wave amplitudes in leads III and V₁ (classified as R ≥ S or R < S). When tested prospectively, the ECG algorithm accurately localized the accessory pathway to 1 of 10 sites around the tricuspid and mitral annuli or at subepicardial locations within the venous system of the heart. Overall sensitivity was 90% and specificity was 99%. The algorithm was particularly useful in correctly localizing anteroseptal (sensitivity 75%, specificity 99%), and mid-septal (sensitivity 100%, specificity 98%) accessory pathways as well as pathways requiring ablation from within ventricular venous branches or anomalies of the coronary sinus (sensitivity 100%, specificity 100%).
Conclusion : A simple ECG algorithm identifies accessory pathway ablation site in Wolff-Parkinson-White syndrome. A truly negative delta wave in lead II predicts ablation within the coronary venous system.     

Safety and efficacy of cryoablation of accessory pathways adjacent to the normal conduction system

Cryoablation of Septal Accessory Pathways. INTRODUCTION: Catheter ablation has become a routine treatment for patients with Wolff-Parkinson-White syndrome because of its low risk and high efficacy; however, radiofrequency ablation in the septum close to the AV node or His bundle still carries a definite risk for AV block. Cryoenergy catheter ablation has recently become available. This technique has specific features, such as the ability to create reversible loss of function to predict the effects of ablation (ice mapping) and the adherence of the catheter tip to the endocardium with freezing, which avoids the risk for dislodgment. Both of these characteristics may minimize the risk of complications. The aim of this study was to analyze the effectiveness and safety of catheter cryoablation in 20 patients with para-Hisian or midseptal accessory pathways (AP). METHODS AND RESULTS: Eleven patients with para-Hisian and 9 patients with midseptal AP underwent catheter cryoablation. Ice mapping at -30 degrees C was performed to ascertain the disappearance of AP conduction and the absence of impairment of AV nodal conduction. If the expected result was obtained, cryoablation was performed by lowering the temperature to -75 degrees C for 4 minutes in order to create a permanent lesion. Cryoablation was successful in all patients using a mean of 1.2 +/- 0.4 applications. Recurrences occurred in 4 patients (20%) who underwent a second successful cryoablation session. No complications were observed. CONCLUSION: Cryoablation appears to be a safe and effective technique for ablation of APs close to the AV node or His bundle because of the ability to predict the acute effects of ablation with ice mapping before creation of an irreversible lesion.     

射频消融治疗儿童阵发性室上性心动过速

作者采用射频消融法治疗３例预激综合征和１例房室结双径路所引起的儿童顽固性阵发性室上速，全部成功，未发生任何并发症。结果表明射频消融是治疗儿童顽固性阵发性室上述的一种有效的新方法     

房室结双径路合并房室旁路的折返性心动过速及射频消融治疗

目的本研究旨在探讨房室结双径路（ＤＡＶＮＰ）合并房室旁路（ＡＰ）的电生理特征和射频消融要求。方法对２１８例阵发性室上性心动过速（ＰＳＶＴ）进行电生理检查，观察ＰＳＶＴ的前传和逆传途径，然后对ＡＰ或房室结慢径（ＳＰ）进行消融治疗。结果２１８例ＰＳＶＴ中检出ＤＡＶＮＰ＋ＡＰ１０例，检出率为４．６％。其中ＳＰ前传、ＡＰ逆传（ＳＰ－ＡＰ折返）４例，快径（ＦＰ）前传、ＡＰ逆传（ＦＰ－ＡＰ折返）１例，ＳＰ－ＡＰ折返并ＦＰ－ＡＰ折返或ＳＰ／ＦＰ交替前传折返４例，ＳＰ前传、ＦＰ逆传（ＡＰ旁观）１例。１０例患者均作ＡＰ消融，诱发房室结折返性心动过速（ＡＶＮＲＴ）的３例加作ＳＰ消融，术后随访均无复发。结论ＤＡＶＮＰ合并ＡＰ者ＡＰ均作为逆传途径，阻断ＡＰ是消融关键；ＡＰ旁观者也应作ＡＰ消融；仅有ＡＨ跳跃延长者不必接受房室结改良；ＡＰ消融者应作ＤＡＶＮＰ电生理检查。     

Exclusion of fluoroscopy during ablation treatment of right accessory pathway in children

INTRODUCTION: The field of pediatric electrophysiology poses many challenges to electrophysiologists. In particular there are two major concerns: (1) to reduce the amount of fluoroscopy exposure to patients and medical staff in the catheterization laboratory and (2) to minimize the number of vascular accesses. Prolonged fluoroscopy times are associated with radiofrequency (RF) ablation of right accessory pathways (APs), particularly the right free-wall AP. The aim of this study was to eliminate the use of fluoroscopy during treatment of right-sided APs in children while using a single-catheter approach. METHODS AND RESULTS: We studied 21 consecutive pediatric patients (mean age 11.3 +/- 3.2 years) with Wolff-Parkinson-White syndrome due to a right AP. To limit fluoroscopy use, we used a three-dimensional navigation system that facilitated reconstruction of a three-dimensional electroanatomic activation map along the tricuspid annulus either on the atrial side during orthodromic AV reciprocating tachycardia or along the ventricular side during anterograde preexcitation. RF application was successful and without complications in 20 patients (success rate 95%); moreover, 19 of the 21 patients underwent a single-catheter procedure. The remaining two patients required an additional quadripolar catheter for atrial stimulation. A mean of 2 +/- 1 RF applications were used during the whole study. CONCLUSION: Our study demonstrates that ablation of right APs in children can be performed without fluoroscopy using a single catheter with minimal amounts of RF applications. Our new technique is associated with high success rates.     

Radiofrequency catheter ablation of two accessory pathways with different unidirectional conduction properties

Summary Simultaneous occurrence of narrow and broad QRS complex tachycardias in patients with WPW syndrome usually indicates a macroreentry in an orthodromic atrioventricular reentry-tachycardia using the AV node as antegrade and the accessory pathway as retrograde conduction and vice versa in an antidromic circuit. We report on a 32-year-old woman with WPW syndrome presenting with both a narrow and a broad QRS complex tachycardia using two accessory pathways with different unidirectional conduction properties in combination of an exclusively antegrade conducting AV node. This case report describes conventional mapping techniques and ablation of this unusual entity of a WPW syndrome.     

Adverse effects of Wolff-Parkinson-White syndrome with right septal or posteroseptal accessory pathways on cardiac function

Aims: Wolff–Parkinson–White syndrome with right septalor posteroseptal accessory pathways causes eccentric septalmechanical activation and may provoke left ventricular (LV)dyssynchrony and dysfunction. The aim of the study was to evaluatethe effect of radiofrequency catheter ablation (RFA) of theaccessory pathways on LV function. Methods and results: Retrospectively, transthoracic echocardiography and electrocardiogramrecordings were analysed in 34 patients (age: 14.2 ±2.5 years) with right septal or posteroseptal accessory pathwaysprior and after (median: 1 day) successful RFA. Results priorto RFA, LV ejection fraction was decreased (<55%) in 19/34patients (56%). After RFA, QRS duration was normalized (129± 23 vs. 90 ± 11, P < 0.0001), LV functionimproved (ejection fraction: 50 ± 10 vs. 56 ±4%, P = 0.0005) and septal-to-posterior wall motion delay asa global measure for LV dyssynchrony decreased (110 ±94 vs. 66 ± 53, P = 0.012). Longitudinal two-dimensionalstrain evaluated in five patients demonstrated a decrease ofleft intraventricular mechanical delay from 292 ± 125to 118 ± 37 ms after RFA. Conclusion: Wolff–Parkinson–White syndrome with right septalor posteroseptal accessory pathways may cause LV dyssynchronyand jeopardize global LV function. Radiofrequency catheter ablationresulted in normalized QRS duration, mechanical resynchronization,and improved LV function. Even in the absence of arrhythmias,RFA of right septal or posteroseptal pathways may be consideredin patients with significantly decreased LV function.     

Inaccuracy of Wolff-Parkinson-white accessory pathway localization algorithms in children and patients with congenital heart defects

INTRODUCTION: ECG algorithms used to localize accessory pathways (AP) in patients with Wolff-Parkinson-White (WPW) syndrome have been validated in adults, but less is known of their use in children, especially in patients with congenital heart disease (CHD). We hypothesize that these algorithms have low diagnostic accuracy in children and even lower in those with CHD. METHODS: Pre-excited ECGs in 43 patients with WPW and CHD (median age 5.4 years [0.9-32 years]) were evaluated and compared to 43 consecutive WPW control patients without CHD (median age 14.5 years [1.8-18 years]). Two blinded observers predicted AP location using 2 adult and 1 pediatric WPW algorithms, and a third blinded observer served as a tiebreaker. Predicted locations were compared with ablation-verified AP location to identify (a) exact match for AP location and (b) match for laterality (left-sided vs right-sided AP). RESULTS: In control children, adult algorithms were accurate in only 56% and 60%, while the pediatric algorithm was correct in 77%. In 19 patients with Ebstein's anomaly, diagnostic accuracy was similar to controls with at times an even better ability to predict laterality. In non-Ebstein's CHD, however, the algorithms were markedly worse (29% for the adult algorithms and 42% for the pediatric algorithms). A relatively large degree of interobserver variability was seen (kappa values from 0.30 to 0.58). CONCLUSIONS: Adult localization algorithms have poor diagnostic accuracy in young patients with and without CHD. Both adult and pediatric algorithms are particularly misleading in non-Ebstein's CHD patients and should be interpreted with caution.