A New Approach for Complete Isolation of the Posterior Left Atrium Including Pulmonary Veins for Atrial Fibrillation

Kumagai, Koji; Muraoka, Soichi; Mitsutake, Chiharu; Takashima, Hideo; Nakashima, Hideko

doi:10.1111/j.1540-8167.2007.00911.x

Cited by 127 publications

(107 citation statements)

References 29 publications

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“…8 In the present study, in addition to the patients with paroxysmal AF, we performed the NCM-guided Box isolation in patients with persistent or longstanding persistent AF, and the success rate of maintaining normal sinus rhythm without any antiarrhythmic drugs was 91%, 73% and 46%, respectively. Monsour et al performed a Fourier analysis of the bi-atrial fibrillatory signals in a sheep model of AF and found that the fastest frequencies recorded during AF occurred in the posterior LA, and that a left-to-right atrial frequency gradient existed during AF.…”

Section: Efficacy Of the Box Isolationmentioning

confidence: 99%

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Noncontact Mapping-Guided Catheter Ablation of Atrial Fibrillation

Kumagai

Nakashima

2009

Circ J

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Circ J 2009; 73: 233 -241 revious studies have demonstrated that the pulmonary veins (PVs) are a source of triggers that initiate and perpetuate atrial fibrillation (AF), 1,2 so radiofrequency catheter ablation that electrically isolates the PVs has been used to treat AF. [1][2][3][4] To improve the clinical outcome, additional linear ablation to modify the substrate of AF has been proposed, 5-7 and we recently described an alternative approach of complete isolation of the posterior left atrium (LA), including all the PVs, for treating AF, namely the Box isolation. 8 However, this procedure is technically challenging because of variant atrial conductions, incomplete lesion lines or recovered conduction gaps being proarrhythmic. Editorial p 227Furthermore, during the procedure, non-PV foci can spontaneously occur, and atrial tachycardia or flutter can be induced after the Box lesion lines are completed. It is difficult to localize focal triggers and multiple conduction gaps, and analyze the mechanism of the atrial tachyarrhythmias with conventional point-to-point mapping. A noncontact mapping (NCM) system with a single-beat mapping capacity can facilitate the identification of the triggering sites of AF. 9-12 NCM allows fast recognition of the earliest depolarization sites, propagation patterns and conduction gaps, and also characterizes the relationship to the underlying anatomical structures. Therefore, we conducted this study to evaluate the feasibility and efficacy of the Box isolation using a NCM system. Methods Patient CharacteristicsThe study population consisted of 188 consecutive patients (166 men, 22 women; mean age 59±11 years) with paroxysmal (n=116), persistent (n=48) and longstanding persistent AF (n=24) who were referred for an electrophysiological study and catheter ablation. Persistent AF was defined as AF that was sustained beyond 7 days and requiring pharmacologic or electrical cardioversion. Longstanding persistent AF was defined as continuous AF of more than 1 year (mean, 91±69 months, range 12-240 months). The mean LA diameter was 41±6 mm and the mean ejection fraction was 63±8% as determined by echocardiography. A mean of 3.0±1.0 antiarrhythmic drugs had been administered, but failed to maintain normal sinus rhythm. None of the patients had been treated with amiodarone within the 6 months preceding the procedure. No structural heart disease was present in 65 patients. Valvular disease was documented in 22 patients, cardiomyopathy in 8, coronary artery disease in 8, and sick sinus syndrome in 2. Hypertension was present in 83 patients. Written informed consent was given by all patients. Electrophysiological StudyAll patients received oral anticoagulants for at least 1 month before the ablation. Transesophageal echocardiography was performed to exclude any LA thrombi and antiarrhythmic drugs were discontinued for 5 half-lives before the procedure. Three 5-Fr quadripolar electrode catheters (St Jude Medical (SJM), St Paul, MN, USA) were placed in the high right atrium, His bundle area, and...

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Section: Efficacy Of the Box Isolationmentioning

confidence: 99%

“…8 Commencing from the lesion at the left inferior PV, the sheath and catheter were rotated clockwise posteriorly and dragged toward the right inferior PV. If AF did not terminate after the Box isolation, sinus rhythm was restored by transthoracic cardioversion.…”

Section: Catheter Ablationmentioning

confidence: 99%

Noncontact Mapping-Guided Catheter Ablation of Atrial Fibrillation

Kumagai

Nakashima

2009

Circ J

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“…PV isolation or box isolation alone is effective for treating paroxysmal AF, 1,28,29) however, not enough for cure of persistent AF or longstanding persistent AF. 30,31) To improve the clinical outcome, extensive ablation, including multiple linear lesions and/or ablation of complex fractionated atrial electrograms (CFAE), has been widely adopted, particularly in patients with persistent AF or longstanding persistent AF.…”

Section: Ablation Of Cfaementioning

confidence: 99%

“…Therefore, we developed a new approach for complete isolation of the posterior LA including all PVs, namely box isolation ( Figure 1). 28) In the posterior LA, there are many arrhythmogenic substrates for AF, including the ganglionated plexi, reentries and triggers. Box isolation can contain these abnormal substrates in the posterior LA.…”

Section: Advantages Of Box Isolationmentioning

confidence: 99%

Box Isolation for Atrial Fibrillation

Kumagai¹

2011

J Arrhythmia

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Since the first report of catheter ablation curing atrial fibrillation (AF), numerous techniques have evolved, from linear ablation to segmental pulmonary vein (PV) isolation, extensive encircling PV isolation, LA linear ablation, ablation of complex fragmented atrial electrograms (CFAE) and stepwise ablation. We developed a new approach for complete isolation of the posterior LA including all PVs, namely box isolation. In the posterior LA, there are many arrhythmogenic substrates for AF, including the triggers, reentries and ganglionated plexi. Box isolation can contain these abnormal substrates in the posterior LA. Box isolation is associated with a high clinical success rate in paroxysmal AF. However, in persistent AF or longstanding persistent AF, only box isolation may not be sufficient, therefore, additional ablation at sites with CFAE outside the box area is needed to improve the clinical outcome. A hybrid approach of combining box isolation with CFAE ablation is highly effective in the majority of patients with persistent AF or longstanding persistent AF. Thus, AF ablation is an effective and safe treatment for AF that offers an excellent chance for a lasting cure. (J Arrhythmia 2011; 27: 255-267)

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“…Our box isolation technique is conducted by means of a non-contact mapping system (NCM) or an electro-anatomical mapping system. 12, 13 Box isolation offers a feasible and safe AF treatment with longterm efficacy. Our results suggest that autonomic denervation by box isolation may cure AF, but data on long-term effects…”

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confidence: 99%

Long-Term Effects of Box Isolation on Sympathovagal Balance in Atrial Fibrillation

Yamaguchi

Kumagai

Nakashima

et al. 2010

Circ J

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Background: Complete isolation of the posterior left atrium, including all pulmonary veins (box isolation), is a feasible and safe atrial fibrillation (AF) treatment method. Data on long-term effects of box isolation on autonomic function, however, remain limited. Methods and Results:A total of 92 patients (paroxysmal AF, n=76; persistent AF, n=16) undergoing box isolation with non-contact mapping were studied. Twenty-four-hours ambulatory electrocardiograms and transthoracic echocardiography were done at baseline and after 2 days, and at 3, 6 and 12 months. Autonomic functions were evaluated by means of heart rate variability (HRV). During a mean follow up of 16±5 months, no AF episodes were detected in 76 patients while AF recurred in 16. Significant long-term HRV attenuations were observed in all patients without AF recurrence, but not in those with AF recurrence. In patients without AF recurrence, the natural logarithm (Ln) high-frequency (HF) decreased significantly from 5.5±1.3 ms 2 (before) to 4.2±0.9 ms 2 (after 12 months, P<0.001) and the ratio of the low-frequency to HF power increased significantly from 2.4±2.0 (before) to 3.4±2.3 (after 12 months, P=0.05). LnHF was significantly lower in patients without than in those with AF recurrence during the 12-month period after ablation. Cardiac function improved significantly in patients without AF recurrence after box isolation. Conclusions:Changes in the sympathovagal balance with box isolation may contribute to AF prevention. (Circ J 2010; 74: 1096 - 1103

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A New Approach for Complete Isolation of the Posterior Left Atrium Including Pulmonary Veins for Atrial Fibrillation

Abstract: This study shows that it is possible to achieve complete isolation of the posterior LA including all PVs without posterior vertical lesions. Box isolation is associated with a high clinical success rate.

Cited by 127 publications

References 29 publications

Noncontact Mapping-Guided Catheter Ablation of Atrial Fibrillation

Noncontact Mapping-Guided Catheter Ablation of Atrial Fibrillation

Box Isolation for Atrial Fibrillation

Long-Term Effects of Box Isolation on Sympathovagal Balance in Atrial Fibrillation

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