Integration of three-dimensional left atrial magnetic resonance images into a real-time electroanatomic mapping system: validation of a registration method

Background: The alignment of three-dimensional (3D) left atrial images acquired by magnetic resonance (MR) with the anatomical information yielded by 3D mapping systems is one of the most critical issues in image integration techniques for catheter ablation of atrial fibrillation (AF). We assessed the accuracy of a simplified method of superimposing 3D MR left atrial images on real-time left atrial electroanatomic maps (registration).
Methods: MR data on the left atrium in 40 patients with drug-refractory AF were imported into the CartoMerge™ (Biosense Webster, Inc., Diamond Bar, CA, USA) electroanatomic mapping system. Registration was obtained by combining "visual alignment" of one endocardial point and "surface registration" of a limited number of points sampled on the posterior wall of the left atrium. The accuracy of the registration process was assessed through a statistical algorithm incorporated into the CartoMerge™ system, and through the percentage of pulmonary veins (PVs) in which electrical isolation was achieved after anatomical ablation.
Results: The mean registration surface-to-point distance and ablation surface-to-point distance were 1.33 ± 0.96 mm and 1.47 ± 1.15 mm, respectively. Upon completion of the circumferential anatomical ablation around the PVs, electrical PV isolation was confirmed by a multipolar circular mapping catheter in 129 of 146 PVs (89%).
Conclusions: Our registration method, which is mainly based on the surface registration of the posterior wall of the left atrium, enables almost 90% of PVs to be isolated by means of an anatomically based catheter ablation approach.     

A New Nonfluoroscopic Navigation System to Guide Pulmonary Vein Isolation

Different techniques have been proposed to treat atrial fibrillation (AF) by catheter ablation. This study compares a new three-dimensional (3D) nonfluoroscopic navigation system with conventional fluoroscopy to guide pulmonary vein (PV) isolation. A total of 60 consecutive patients with paroxysmal or persistent AF were randomly assigned to 3D-guided ablation (group 1, n = 30), versus conventional fluoroscopy guidance ablation (group 2, n = 30). Complete PV isolation was achieved in both groups. The mean duration of fluoroscopy exposure (22 ± 8 vs 56 ± 10 minutes), and radiofrequency delivery (5 ± 1 vs 10 ± 3 minutes) were significantly shorter in group 1 than in group 2, P < 0.05 for both comparisons). The mean procedural time in group 1 was longer (225 ± 15 minutes) than in group 2 (156 ± 10 minutes, P < 0.05) due to the learning curve and time spent to generate the 3D maps. Over a mean follow-up of 7 ± 2 months, 6 patients (20%) in group 2 had AF recurrences compared to 3 patients (10%) in group 1 (ns). The new nonfluoroscopic 3D system allows a high-resolution reconstruction of the left atrium and PVs. It significantly reduces the mean radiofrequency delivery and fluoroscopy times as opposed to ablation performed under fluoroscopy guidance.     

A Clinical Study of Patients with and Without Recurrence of Paroxysmal Atrial Fibrillation After Pulmonary Vein Isolation

Patients with paroxysmal atrial fibrillation (PAF) can be treated by pulmonary vein (PV) isolation. However, the recurrence rate after this procedure is relatively high. We sought to evaluate the quality of life (QOL) of patients with PAF recurrence after PV isolation and to analyze factors related to recurrences. Seventy-two drug-refractory PAF patients (59 men, 13 women, mean age 52 ± 10) were included. PV isolation was based on the disappearance of PV potentials recorded from a Lasso catheter after segmental ostium ablation. Automatic foci were observed in 47 patients (65.3%) during the procedure. A mean of 3.1 ± 0.9 PVs was isolated. Patients were followed for a mean of 10.3 ± 5.1 months, during which 27 experienced >1 episode of PAF. QOL was scored from 0 (situation before ablation) to 10 (no episode after ablation) based on a questionnaire completed by 69 patients (95.8%). QOL was judged very good in 26 patients (none with PAF recurrences), better in 30 (15 with PAF recurrences), unchanged in 11 (10 with recurrences), and worse in 2 patients with PAF recurrences. Longer histories of PAF and a lower percentage of patients with automatic foci identified during the procedure were observed in the group with, than in the group without recurrences (P < 0.05). PV isolation improved QOL in patients with PAF, including in patients with recurrences. The length of PAF history and observation of automatic foci may be of importance for recurrences of PAF during long-term follow-up.     

Impact of integration of multislice computed tomography imaging into three-dimensional electroanatomic mapping on clinical outcomes, safety, and efficacy using radiofrequency ablation for atrial fibrillation

BACKGROUND: Circumferential radiofrequency catheter ablation (RFCA) around the orifices of the pulmonary veins (PV) is a curative catheter-based therapy of paroxysmal, persistent, and permanent atrial fibrillation (AF). Integration of multislice computed tomography into three-dimensional electroanatomic mapping to guide catheter ablation has been shown to be accurate and feasible. This study investigated whether the use of such sophisticated imaging technology translates into better clinical outcomes, procedural efficacy, and safety in comparison with a control group treated with conventional three-dimensional electroanatomic mapping. METHODS: A total of 100 consecutive patients (85 male, mean age 55 +/- 9 years) with multi-drug-resistant AF underwent RFCA. In this study we used a wide area circumferential approach with confirmed PV isolation (requiring additional ablations at the ostial level) and further lines as needed. RESULTS: Comparison of outcome data between the conventional electroanatomic mapping (Carto XP, Biosense Webster, Diamond Bar, CA, USA) and the image integration technology (Carto MERGE, Biosense Webster) resulted in a significant improvement in procedural success for the image integration group (85.1% vs 67.9%; P = 0.018). No single case of significant PV stenosis occurred in the Carto MERGE group versus three significant stenoses in the conventional group (P = 0.098). Both procedure and fluoroscopy times remained unchanged. CONCLUSION: Multislice computed tomography image integration into electroanatomic mapping significantly improves the success of wide area circumferential ablation with confirmed isolation of the PV and additional lines. In addition, the safety of radiofrequency ablation with regard to the occurrence of PV stenosis is increased in comparison with a control group using conventional electroanatomic mapping alone. Procedural efficacy remains unchanged.     

Usefulness of the Adenosine Triphosphate with a Sufficient Observation Period for Detecting Reconduction after Pulmonary Vein Isolation

Background: Although reconduction after pulmonary vein (PV) isolation is considered to play a key role in the recurrence of paroxysmal atrial fibrillation (AF), there have been few reports regarding the precise time course of early reconduction. Several studies have suggested that transient PV reconduction facilitated by adenosine may predict long-term AF recurrence. This study was designed to clarify the incidence and time course of early reconduction after PVI during the procedure and to confirm whether the use of ATP after a certain observation period was useful to detect early reconduction after PVI.
Methods: In 21 patients (18 males, 56 ± 11 years) with drug refractory AF, radiofrequency circumferential PV antrum ablation was performed in all 4 PVs. After the completion of isolation, electrograms in each PV were repeatedly recorded (1.98 ± 0.57 times per PV) using a circular mapping catheter for an observation period of 87 ± 29 minutes. After isolation of all 4 PVs, 30 mg of adenosine triphosphate (ATP) was administered during isoproterenol infusion.
Results: PV electrical isolation was initially achieved in all 81 PVs. During the observation period, 12 (15%) PVs in 10 (48%) of 21 patients exhibited spontaneous reconduction. Among the remaining 69 PVs, 8 (12%) additional PVs had reconduction with the use of ATP. All PV reconduction was successfully eliminated by 4.5 ± 2.2 additional radiofrequency applications.
Conclusion: A sufficient observation period and the use of ATP are useful to detect early reconduction after PV isolation.     

Role of Pulmonary Veins Isolation in Persistent Atrial Fibrillation Ablation:

Background: The role of pulmonary veins (PV) isolation in patients with persistent atrial fibrillation (AF) is still debated. The aim of this study was to evaluate the adjunctive role of PV isolation in patients with persistent AF who underwent circumferential PV ablation (anatomical approach).
Methods: We treated 97 consecutive patients presenting with drug-refractory persistent AF by an anatomical approach (group A, n = 36, mean age = 60 ± 8 years, 29 males) or an integrated approach (group B, n = 61, mean age 59 ± 10 years, 48 males). In all patients, radiofrequency (RF) ablation was performed by means of a nonfluoroscopic navigation system, in order to anatomically create circumferential lines around the PV. In group B, the persistence of PV potentials was ascertained with a multipolar circular catheter. If PV potentials persisted, RF energy targeting the electrophysiological breakthroughs was delivered to disconnect the PV. Past a 2-month period of observation, success was defined as absence of any atrial tachyarrhythmia recurrence lasting >30 seconds.
Results: Total procedure duration (220 ± 62 minutes vs 140 ± 43 minutes, P < 0.001), fluoroscopy time (35 ± 15 minutes vs 17 ± 9 minutes, P < 0.001), and RF delivery time (48 ± 22 minutes vs 27 ± 9 minutes, P < 0.001) were significantly longer in group B than in group A. One cardiac perforation occurred in group A. After 15 ± 9.1 months, 21 patients in group A (58%) and 34 patients in group B (56%) were free of atrial tachyarrhythmia recurrence (P = 0.9).
Conclusions: In patients with persistent AF, who underwent an anatomical approach, electrophysiological confirmation of PV disconnection significantly increased the fluoroscopy and procedural times, without effect on the long-term outcomes.     

Pulmonary vein morphology before and after segmental isolation in patients with atrial fibrillation

BACKGROUND: The morphology of the pulmonary veins (PVs) before and after segmental isolation of the PVs has not been sufficiently characterized. METHODS AND RESULTS: Multi-slice computed tomography was performed before and 3 +/- 1 months after ablation in 30 patients with atrial fibrillation who underwent PV isolation. Before ablation, PV narrowing (> or =25% luminal reduction) was found in nine (8%) PVs. After ablation, de novo PV narrowing was found in 24 PVs (26%) and was detected only in the supero-inferior direction in 14 PVs (58%). The diameter reduction inside the PVs after ablation was greater in the supero-inferior direction (14 +/- 12%) than in the antero-posterior direction (9 +/- 13%; P < 0.0001). In the ablated PVs, the PV trunk was shorter than before ablation (P < 0.0001). The reduction in the diameters of both the PV ostium and the ablation site in the ablated PVs, as well as the diameter of the PV ostium in the nonablated PVs, correlated with the decrease in the left atrial diameter. Shortening of the PV trunk correlated with the severity of PV narrowing, but it was not related to the percent diameter reduction of the left atrium. PV narrowing before or after ablation did not result in any clinical consequences. CONCLUSIONS: PV narrowing is present in about 10% of PVs before ablation. Asymmetric luminal reduction and longitudinal shrinkage of the PV trunk occur after ablation. Reverse remodeling of the PV and contraction of the PV wall may contribute to the reduction in the PV diameter. PV morphology should be assessed with multi-directional views to avoid missing heterogeneous legions.     

Feasibility of Pulmonary Vein Ostia Radiofrequency Ablation in Patients with Atrial Fibrillation: A Multicenter Study (CACAF Pilot Study)

STABILE, G., et al.: Feasibility of Pulmonary Vein Ostia Radiofrequency Ablation in Patients with Atrial Fibrillation: A Multicenter Study (CACAF Pilot Study) Radiofrequency (RF) catheter ablation has been proposed as a treatment of atrial fibrillation (AF). Several approaches have been reported and success rates have been dependent on procedural volume and operator's experience. This is the first report of a multicenter study of RF ablation of AF. We treated 44 men and 25 women with paroxysmal   (n = 40)   or persistent   (n = 29)   , drug refractory AF. Circular pulmonary vein (PV) ostial lesions were deployed transseptally, during sinus rhythm   (n = 42)   or AF  ( n = 26)   , under three-dimensional electroanatomic guidance. Cavo-tricuspid isthmus ablation was performed in 27 (40%) patients. The mean procedure time was   215 ± 76   minutes (93–530), mean fluoroscopic exposure   32 ± 14   minutes (12–79), and mean number of RF pulses per patient   56 ± 29   (18–166). The mean numbers of separate PV ostia mapped and isolated per patient were   3.9 ± 0.5   , and   3.8 ± 0.7   , respectively. Major complications were observed in 3 (4%) patients, including pericardial effusion, transient ischemic attack, and tamponade. At 1-month follow-up, 21 of 68 (31%) patients had had AF recurrences, of whom 8 required electrical cardioversion. After the first month, over a mean period of   9 ± 3   (5–14) months, 57 (84%) patients remained free of atrial arrhythmias. RF ablation of AF by circumferential PV ostial ablation is feasible with a high short-term success rate. While the procedure and fluoroscopic exposure duration were short, the incidence of major cardiac complications was not negligible. (PACE 2003; 26[Pt. II]:284–287)     

Atrio-Pulmonary Vein Conduction Delay during Pulmonary Vein Isolation for Atrial Fibrillation Is Related to Vein Anatomy, Age, and Focal Activity

Background: During pulmonary vein isolation for treatment of atrial fibrillation (AF), a significant delay in atrio-pulmonary vein (PV) conduction is often observed. We sought to investigate this conduction delay in various PV in individual patients.
Methods: We studied 385 AF patients (mean age: 54 ± 11 years, 74 women) who underwent segmental PV isolation (PVI). A circular decapolar catheter was used to record electrograms at the PV ostia. The time delay from local atrial potential to PV potential was measured in each vein. Conduction delay (CD) was defined as the longest time interval >20 ms observed during PVI.
Results: For patients treated for the first time, CD was more frequently observed in the left common and the right and left superior PVs (84.2%, 67.9%, and 66.2%, respectively) and less frequently in the left and right inferior and right middle PVs (54.3%, 40.0%, and 30.8%, respectively). Veins with CD required more ablation applications (12.4 vs 9.9) and a higher ablated segmental fraction (72.3% vs 63.7%). CD was observed in 75.2% (109/145) of the PVs in which focal activity was detected. Older patients had a higher incidence of PVs with CD than younger patients. There were no gender differences.
Conclusions: The incidence of CD was highest in the left common and superior PVs, in older patients and in PVs with focal activity. PVs with CD required more ablation applications and a larger area of ablation around the ostia. These observations were not found during repeat procedures.     

心房颤动患者环肺静脉左房线性消融术后的护理

目的 探讨心房颤动(房颤)患者环肺静脉左房线性消融术后的观察和护理要点.方法 对3l例房颤患者采用CARTO电解削标测系统及双Lasso表测电极技术,分别进行环左、右侧肺静脉线性消融;消融终点为肺静脉电位消失,左房-肺静脉双向传导阻滞,并对观察护理要点进行总结.结果 患者初次消融术后平均随访(245±65)d,21例无复发,8例复发房性心律失常包括5例典型房扑、2例其他房性心动过速、1例阵发性房颤、2例左上肺静脉电位未完全隔离者仍持续房颤.除1例持续性房颤外,9例接受了再次消融术,8例射频消融成功并随访(192±92)d无复发.2次射频消融术后总成功率为92.8%.结论 护理人员应根据患者在行环肺静脉左房线性消融术术前、术中、术后,对出现的症状进行有效的护理措施,以解除患者的痛苦.     

Incremental value of isolating the right inferior pulmonary vein during pulmonary vein isolation procedures in patients with paroxysmal atrial fibrillation

Electrical isolation of the left superior, left inferior, and right superior pulmonary veins (PVs) is often, but not always, effective in eliminating paroxysmal atrial fibrillation (PAF). The incremental clinical value of also isolating the right inferior PV has not been well defined. PV isolation by ostial applications of radiofrequency energy guided by PV potentials was performed in 176 consecutive patients (mean age 52 +/- 11 years) with PAF. The left superior, left inferior, and right superior PVs were targeted in 106 patients, and all four PVs were targeted 70 patients. Successful isolation was achieved in 96% of targeted PVs. The mean duration of follow-up was 15 +/- 7 months. At 1-year follow-up, 58% of patients in whom three PVs were isolated were free of recurrent PAF in the absence of antiarrhythmic drug therapy, compared to 73% of patients in whom all four PVs were isolated (P = 0.07). There is a trend towards a better outcome when all four PVs are isolated than when only the three major PVs are isolated. Whenever feasible, the right inferior PV should be isolated along with the other three PVs during the first ablation procedure in patients with PAF.     

Nonfluoroscopic magnetic electroanatomic mapping to facilitate focal pulmonary veins ablation for paroxysmal atrial fibrillation

RF ablation of ectopic foci in the pulmonary veins (PVs) is a promising treatment for patients with paroxysmal AF. The aim of this study was to evaluate the feasibility of using nonfluoroscopic magnetic electroanatomic mapping of PV during spontaneous or induced ectopy to facilitate focal ablation procedure. The study included 35 patients with drug refractory paroxysmal AF who underwent focal RF ablation of the PV. In 10 (29%) patients, mapping and RF ablation procedures were performed using the nonfluoroscopic magnetic electroanatomic mapping system to enable automatic capture of the location and the timing of the ectopy. As a control, 25 patients underwent conventional endocardial activation mapping technique. There were no significant differences in the clinical characteristics between the two groups. Overall procedural duration was similar between them (199 +/- 52 vs 221 +/- 82 minutes, P > 0.05). However, the mean fluoroscopy time (25 +/- 6 vs 52 +/- 12 minutes, P = 0.01) and the mean number of RF applications (5 +/- 3 vs 12 +/- 9, P = 0.02) were significantly less in patients who underwent electroanatomic mapping. There were no significant differences between the two groups in the acute (90 vs 84%) and long-term success rate (60 vs 56%) after a mean follow-up of 12 +/- 9 months. In conclusion, RF ablation of ectopic foci using nonfluoroscopic magnetic electroanatomic mapping of PVs during spontaneous or induced ectopy is useful even in patients with a limited number of ectopy, and is associated with a similar success rate, but less fluoroscopy time and RF application compared to the conventional approach.     

Segmental pulmonary vein ablation: success rates with and without exclusion of areas adjacent to the esophagus

Background: Catheter ablation has become the first line of therapy in patients with symptomatic recurrent, drug‐refractory atrial fibrillation (AF). The occurrence of an atrioesophageal fistula is a rare but serious complication after AF‐ablation procedures. This risk is even present during segmental pulmonary vein (PV) ablation procedures because the esophagus does frequently have a very close anatomical relationship to the right or left PV ostia. The aim of the present study was to analyze whether the exclusion of areas adjacent to the esophagus does have a significant effect on the success rates after segmental pulmonary vein ablation procedures. Methods: Forty‐three consecutive patients with symptomatic paroxysmal AF were enrolled in this study. In all patients, a segmental PV ablation procedure was performed. The procedures were facilitated by a 3D real‐time visualization of the circumferential mapping catheter placed in the pulmonary veins using the NavX? system (St. Jude Medical, St. Paul, MN, USA; open irrigated tip ablation catheter; 43°C; 30 W). In 21 patients, a complete ostial PV isolation was attempted regardless of the anatomical relationship between the ablation sites and the esophagus (group A). In the remaining 22 patients, the esophagus was marked by a stomach tube and areas adjacent to the esophagus were excluded from the ablation procedure (group B). After discharge, patients were scheduled for repeated visits at the arrhythmia clinic at 1, 3, and 6 months after the ablation procedure. Results: The segmental pulmonary vein ablation procedure could be performed as planned in all patients. In group A, all pulmonary veins could be isolated successfully in 14 out of 21 patients (67%). A mean number of 3.7 pulmonary veins (SD ± 0.5 PVs) were isolated per patient. The main reasons for an incomplete PV isolation were: small diameter of the PVs, side branches close to the ostium, or poorly accessible PV ostia. In group B, all PVs could be isolated successfully in only 12 out of 22 patients (55%; P = 0.54). A mean number of 3.2 PVs (SD ± 0.9 PVs) were isolated per patient (P = 0.05). This was mostly due to a close anatomical relationship to the esophagus. The ablation strategy had to be modified in 16/22 patients in group B because of a close anatomical relationship between the left (n = 10) or right (n = 6) PV ostia and the esophagus. After 3 months, the percentage of patients free from an AF recurrence was not significantly different between the two groups (90% vs 95%; P = 0.61). After 6 months, there was no significant difference between the success rates either (81% vs 82%; P = 1.0). There were no major complications in both groups. Conclusions: The exclusion of areas adjacent to the esophagus results in a moderately higher percentage of incompletely isolated PVs. However, it does not have a significant effect on the AF recurrence rate during short‐term and mid‐term follow‐up.     

Characteristics in image integration system guiding catheter ablation of atrial fibrillation with a common ostium of inferior pulmonary veins

BACKGROUND: Common ostium of the inferior pulmonary veins (PVs) is a kind of unusual variation in pulmonary venous drainage to the left atrium (LA), whose feature of anatomy, electrophysiology, and catheter ablation is rarely demonstrated, and the consecutive series of research for catheter ablation of atrial fibrillation (AF) in patients with that anomaly have not been reported. METHODS: A total of 1,226 patients with drug-refractory AF received magnetic resonance angiography (MRA) or multidetector computed tomography (MDCT) scan before ablation. Electrophysiological mapping was used to detect the focal triggers in paroxysmal AF. Basic catheter ablation strategy was circumferential PV isolation with "tricircle" under the guidance of image integration system: two circles surround two superior PVs, and the other surround the common trunk. RESULTS: LA and PVs reconstruction by image integration system showed a common pulmonary venous ostium of the right and left inferior PVs before ablation in 11 patients (0.9%). This anomaly could be classified into two types: type A without a short common trunk of inferior PVs and type B with a short common trunk. Fifty-seven percent paroxysmal AF was revealed focal triggers in the common ostium. The success rate of that strategy was 90%. CONCLUSION: Common ostium of inferior PVs could be classified into two types according to the presence of a short common trunk or not. The common ostium was usually an important triggering focus in paroxysmal AF. Catheter ablation strategy of circumferential PV isolation with "tricircle" under the guidance of image integration system would be a good choice.     

Mapping and Isolation of the Pulmonary Veins Using the PVAC Catheter

Objectives: We aimed to investigate the feasibility, efficacy, and safety of the pulmonary vein ablation catheter (PVAC) catheter (a novel multielectrode catheter using duty‐cycled bipolar and unipolar radiofrequency energy, Medtronic, Minneapolis, MN, USA) to completely isolate the pulmonary veins (PVs). Methods: Twenty‐seven patients (60 ± 8 years) with paroxysmal atrial fibrillation (AF) underwent PV isolation with the PVAC catheter. PVAC was used for both mapping and isolation of the PVs (PVAC‐guided ablation). After PVAC ablation, presence/absence of PV potentials (PVP) was verified using a conventional circular mapping catheter. In case of residual PVP on the circular catheter, PVAC ablation was continued. Results: After PVAC‐guided ablation 99 of 106 PVs (93%) and 21 of 27 patients (78%) were proven to be isolated. Failure to isolate was due to a mapping failure in four right‐sided PVs and a true ablation failure in three right‐sided PVs. After continued PVAC ablation, 103 of 106 PVs (97%) and 25 of 27 patients (93%) were shown to be isolated. The total procedural time from femoral vein access to complete catheter withdrawal was 176 ± 25 minutes. The actual dwelling‐time of the PVAC within the left atrium was 102 ± 37 minutes. Esophageal T° rise to >38.5° occurred in nine of 19 monitored patients (47%). Conclusions: (1) PVAC‐guided ablation (i.e., mapping and ablation with a single catheter) results in isolation of all PVs in 73% of the patients. (2) An additional circular mapping catheter is required to increase complete isolation rate to 93% of the patients. (3) Given the esophageal T° rise in almost 50% of patients, safety precautions are needed. (PACE 2010; 33:168–178)     

Full-motion two- and three-dimensional pulmonary vein imaging by intracardiac echocardiography after pulmonary vein isolation

Background: The pulmonary veins (PVs) are topographically complex and motile, so angiographic visualization of the PVs anatomy is limited. An imaging technique that accurately portrays the pulmonary vein ( PV) anatomy would be valuable during and after catheter ablation procedures.
Purpose: We investigated whether three-dimensional (3D) intracardiac echocardiography (ICE) can visualize radiofrequency (RF)-induced tissue changes after PV isolation.
Methods: We performed 3D ICE studies with a 9F, 9-MHz ICE catheter after segmental or extended PV isolation. The ICE catheter was placed 3–4 cm inside the PV ostium and mounted onto a pullback device. Sequential two-dimensional (2D) images of the full length of the vein were obtained in 0.3 mm steps with cardiac and respiratory cycle gating. Each image was fed into a computer, and the aggregate data set was reconstructed into a 3D, full-motion image. RF lesion location and lesion size were studied on 67 pullback images from 29 patients.
Results: The 2D and 3D reconstruction was possible for 27 left superior PVs, 13 left inferior PVs, 26 right superior PVs, and one right inferior PV. The ablation site was identified 3–7 mm inside the PV ostium, and a 1/2 – 4/5 circumferential area was ablated with no clinically relevant stenosis. No significant differences were found on the ablated area or ablation site between segmental and extensive PV isolation.
Conclusion: The 2D and 3D ICE of the PVs provides detailed anatomical information of the proximal PVs, and RF-induced tissue changes in the PV wall can be visualized by ICE.     

Differentiating the Ligament of Marshall from the Pulmonary Vein Musculature Potentials in Patients with Paroxysmal Atrial Fibrillation: Electrophysiological Characteristics and Results of Radiofrequency Ablation

TAI, C.-T., et al. : Differentiating the Ligament of Marshall from the Pulmonary Vein Musculature Potentials in Patients with Paroxysmal Atrial Fibrillation: Electrophysiological Characteristics and Results of Radiofrequency Ablation. It was reported that paroxysmal atrial fibrillation (PAF) can be initiated by ectopic atrial beats originating from the pulmonary vein (PV) or left atrial tract (LAT) within the ligament of Marshall (LOM). The aim of this study was to differentiate the LAT from the PV potentials, and to investigate the results of radiofrequency ablation guided by these potentials. Ten patients (  age 60 ± 12 years  ) with PAF who had a recording of double potentials (DPs) in or around the left PV were included. Group I had five patients with the second deflection of DPs (D2) due to activation of the LAT, and Group II had five patients with D2 due to activation of the PV musculature. There were no significant difference in the isoelectric interval between DPs, the activation time, and amplitude of D2 between Groups I and II. During distal coronary sinus (CS) pacing, the CS ostium (CSO) to D2 interval was shorter compared with that during sinus rhythm in Group I (  39 ± 19 vs 71 ± 25 ms, P = 0.04  ), but was longer in Group II (  96 ± 16 vs 44 ± 19 ms, P = 0.04  ). During ectopic activation, three patients in Group I, but no Group II patients, had transformation of recorded DPs into triple potentials. Radiofrequency ablation guided by the earliest activation of the LAT potential was performed with transient suppression of PAF, but ablation guided by the earliest activation of the PV potentials had a high success rate in eliminating PAF. In conclusion, differentiating the LAT from the PV potentials for initiation of PAF is feasible by an electrophysiological approach, and may be important for radiofrequency ablation of PAF.     

Nonpulmonary Vein Foci:

Though the majority of foci triggering atrial fibrillation (AF) have been mapped to the pulmonary veins (PV), recurrence of paroxysmal AF after isolation of all four pulmonary veins indicates the presence of other foci. In a series of 160 consecutive patients who underwent PV ablation, endocardial mapping of AF and ectopy recurring after PV isolation was performed. Thirty-six patients (24%) had a total of 85 non-PV foci; 39 were mapped to the ostia of ablated PVs, 30 to the posterior left atrium (LA), 5 to other parts of the LA, 5 to the right atrium (RA), 4 to the coronary sinus (CS), and 3 to the superior vena cava (SVC) (including one persistent left SVC). Mapping was confirmed by successful ablation. At least 16 foci could not be localized and after a follow-up of 8 ± 6 months, 68% of patients were free of AF without any antiarrhythmic treatment. The occurrence of non-PV foci correlated with recurrence of AF, perhaps as a correlate of insufficient ostial ablation. These data reinforce the requirement for more proximal disconnection of the PVs by performing ablation within the LA. In patients with non-PV foci that are difficult to map conventionally, the use of surface ECG data, or multielectrode contact or noncontact mapping arrays, or substrate modifying/excluding ablation may be helpful in ablating these foci and therefore eliminating AF. (PACE 2003; 26[Pt. II]:1631–1635)     

Left Atrial Linear Ablation to Modify the Substrate of Atrial Fibrillation Using a New Nonfluoroscopic Imaging System

Linear left atrial ablation is performed in combination with pulmonary vein (PV) isolation to improve the clinical results of atrial fibrillation (AF) ablation. These procedures require long procedures and fluoroscopic exposure. The aim of the present study was to evaluate the performance of a new, nonfluoroscopic, real-time, three-dimensional navigation system for linear ablation at the left atrial roof and mitral isthmus. The study included 44 patients (54 ± 10 years of age, 5 women) with drug-refractory AF, who underwent roof line or mitral isthmus linear ablation after 4-PV isolation. In 22 patients, ablation was performed with the navigation system (test group), and in the remainders linear ablation was performed with fluoroscopic guidance alone (control group). Conduction block was achieved in 20 patients (91%) in test group, and 21 patients (95%) in the control group (ns). Use of the navigation system was associated with a shorter fluoroscopic exposure for roof line (5.6 ± 3.0 minutes vs 8.7 ± 5.0 minutes, P < 0.05), and a trend for mitral isthmus ablation (7.8 ± 7.8 minutes vs 12.1 ± 5.9 minutes). It was also associated with a trend toward shorter procedure times for roof line (15.3 ± 8.6 minutes vs 22.9 ± 16.8 minutes) and mitral isthmus line (20.2 ± 15.8 minutes vs 32.0 ± 7.6 minutes) but no difference in duration of radiofrequency delivery. There was no procedural complication. The use of this new nonfluoroscopic imaging system was associated with a shorter fluoroscopic exposure as well as a trend toward shorter duration of linear ablation procedures for AF.     

Site localization and characterization of pain during radiofrequency ablation of the pulmonary veins

BACKGROUND: Characteristics of radiofrequency (RF) lesions producing pain with an 8-mm catheter during pulmonary vein (PV) ablation have not been prospectively studied. METHODS: We studied 46 (30 men, age 56 +/- 10 years) patients with AF who underwent RF ablation of PVs. PV isolation was achieved by using an 8F, 8-mm Biosense ablation catheter (Biosense Webster, Diamond Bar, CA, USA) guided by intracardiac echocardiography (ICE). An electroanatomic map was used to document the location of all RF lesions and the time; PV location and maximum temperature of every lesion were recorded. Location of the esophagus was determined by magnetic resonance imaging prior to the procedure and by both ICE and barium swallows during procedure. RESULT: A total of 1,448 (33 +/- 12) RF lesions were delivered to 180 veins. Thirty-nine patients (85%) had at least one lesion associated with pain (mean: 8 +/- 5 lesions) during ablation. The RF generator setting during lesions resulting in pain sensation was 48.6 +/- 7.0 Watts and 51.5 +/- 2.9 degrees C. Maximum temperature attained at the time of pain sensation was 45.7 +/- 4.2 degrees C. By logistic regression analysis the left superior PV (OR 1.54, CI 1.06-2.24, LS vs RI, P < 0.05) and left inferior PV (OR 2.74, CI 1.79-4.19, LI vs RI, P < 0.001) location were both positively correlated with the production of pain. The location of lesions associated with pain was not near the esophagus during any of the pain-producing lesions. CONCLUSION: Pain sensation is relatively common during RF ablation of PVs. There was no correlation between pain and the location of esophagus. Pain was more common during RF ablation of left inferior and left superior PVs.