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A 51-year-old man, who had a history of open heart surgery for corrected transposition of great arteries, presented with palpitation due to atrial tachycardia. A propagation map using three-dimensional electroanatomical mapping (CARTO3) showed atrial flutter and underwent linear ablation successfully. This case highlights the difficulty of diagnosis before mapping following a complicated cardiac operation and the usefulness of three-dimensional mapping.

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 post erior 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.

The mechanisms for termination of atrial fibrillation (AF) during ablation are not clarified. We reported that dominant frequency (DF) decrease to

Aims: We sought to investigate the anatomy characteristics of cavotricuspid isthmus (CTI) and its influence on linear ablation navigated by CARTO. Methods: A total of 55 patients who underwent radiofrequency catheter ablation navigated by CARTO were enrolled in this study. The anatomy characteristics of CTI (length, depth) and the ablation time were measured and analyzed under the guide of CARTO. Result: 1. The length of CTI in pouch type was significantly longer than that in flat types (n=23, 45.5±7.5 mm vs. n=22, 36.1±8.9 mm, P=0.0015). There was a correlation between the ablation time and the depth of CTI (r=−0.505, P =35 mm, n=41) was much longer than that of group 1 (1485±681 s vs. 804±305 s, P=0.0007). 2. Significant differences were seen in the depth of CTI and the ablation time between those AF patients with and without CTI dependent AFL. Conclusion: The ablation time of CTI linear ablation was positively correlated to the depth of CTI. The ablation time were prolonged in those CTI with length >=35 mm and most of them were pouch type. When CTI dependent AFL was encountered in AF ablation procedure, those CTI were deeper and often presented as pouch or concave type which needed a longer ablation time.

Methods: We created a swine AF model using 3 weeks monensin administration to create atrial inflammation. At terminal surgery, an electrophysiological study was performed with the EnSite array system, and echocardiography was used to evaluate changes in cardiac function. Blood samples and cardiac tissues were assessed in 9 monensin-treated swine. In those with inducible AF, we created a linear ablation line in the anterior left atrium (LA) and evaluated the impact of linear ablation on episodes of paroxysmal AF. Results: Monensin created an AF substrate characterized by increased atrial but not ventricular fibrosis in swine. Monensin did not cause consistent changes in cardiac function, or plasma D-dimer or CRP levels. Electro-physiological study showed transverse conduction disturbances at the LA roof and anterior LA. In contrast, vertical conduction of LA during AF was almost simultaneous and no conduction disturbance was observed. Based on this observation, we created a linear ablation line at the roof of LA as well as at the anterior LA to LA appendage in 2 swine. AF was easily induced before, but not inducible after ablation. Conclusion: In this model, transverse conduction disturbance in the roof and anterior LA were critical for AF maintenance. Linear ablation that blocked transverse conduction in LA was very effective in preventing AF.

Objective Circumferential pulmonary vein isolation (CPVI) has been considered the cornerstone of radiofrequency catheter ablation (RFCA) for atrial fibrillation (AF). However, it is unclear whether linear ablation in addition to CPVI improves clinical outcome. Design Prospective randomised study to compare the efficacy of CPVI and CPVI with additional linear ablation in patients with paroxysmal AF (PAF). Setting University hospital. Patients This study enrolled 156 patients (male 76.3%, 55.8±11.5 years old (mean±SD)) who underwent RFCA for PAF. Interventions CPVI (n=52), CPVI+roof line (CPVI+RL; n=52) and CPVI+RL+posterior inferior line (CPVI+PostBox; n=52). Main outcome measures Procedure time, ablation time and clinical outcome. Results (1) The CPVI group showed shorter total procedure time (180.4±39.5 min vs 189.6±29.0 min and 201.7±51.7 min, respectively (mean±SD); p=0.035) and ablation time (4085.5±1384.1 s vs 5253.5±1010.9 s and 5495.0±1316.0 s, respectively; p

Background: Atrial substrate modification with linear ablation and complex fractionated atrial electrograms (CFAE) ablation is considered to be necessary in patients with nonparoxysmal atrial fibrillation (AF) without respond to pulmonary vein isolation (PVI). The evaluation of the atrial substrate characteristics before and after PVI has not been evaluated fully. The aim of this study was to examine the impact of circumferential PVI on the atrial substrate characteristics. Methods and Results: Thirty consecutive AF patients (63±11 years, 15 paroxysmal and 15 persistent) underwent mapping and catheter ablation using a NavX system. The biatrial substrate characteristics was evaluated using the fractionation analysis from fractionated intervals and frequency analysis from dominant frequencies (DF) before and after PVI. Circumferential PVI was performed in all patients. There were significant differences between before and after PVI of the proportion of continuous CFEs (4.7±5.3% and 3.0±4.4%, P

Introduction: There are controversies regarding predictors of freedom from post-ablation recurrences in persistent AF with different degrees of progression of anatomical atrial remodeling. Methods and Results: Consecutive 254 patients with persistent AF (AF duration (AFD): 68±77 months, LA diameter (LAD): 46±5 mm) underwent initial ablation session for anatomical linear ablation in LA and RA after circumferential PV isolation with procedural endpoint of AF elimination. AF termination (n=23) or conversion to AT (n=63) or flutter (n=22) was achieved in 108 patients (42.5%), while AF persisted after completion of ablation protocol in the remaining 146 patients (57.5%). One hundred ninety-eight patients were followed beyond blanking period (2 months) for 289±226 days after initial procedure and 104 patients (53%) were free from AF/AT recurrences. Kaplan-Meier analysis showed recurrence-free survival rate after initial procedure was significantly higher in those with procedural AF elimination than in those without [54/85 (64%) vs. 50/113 (44%); P=0.01]. Multivariate analysis showed that AF duration and procedural AF elimination were independent predictors of freedom from post-ablation recurrence (P 51 mm or AFD =/> 5 years, while it remained significant among those with LAD 5 years and/or LAD =/> 51 mm.

Background: In longstanding, persistent AF, AF often converts into intermediary atrial tachycardia (iAT) before restoration of sinus rhythm during ablation procedure and recurrent ATs (rATs) are commonly observed during post-ablation follow-up. Whether iAT and rAT documented in the same patient are identical or not is, however, unknown.Methods: This study included consecutive 48 patients (40 males, age: 66±8 years) in whom AF converted into an iAT during anatomical linear ablation and subsequently a rAT was documented during post-ablation follow-up. The P-wave polarity in 12-lead ECGs of iAT and rAT was evaluated in leads I, II, III, aVF, V1 and V6, and it was categorized into one of positive, negative, biphasic (positive/negative or negative/positive) and isoelectric. The P-wave matching score (0–6) was calculated by adding each one point when the P-wave polarity was identical between the ECGs of iAT and rAT in each ECG lead.Results: Mean P-wave matching score was 5.6±0.9, and it was 6 in 40 (84%), 5 in 2 (4%), 4 in 2 (4%), and 3 in 4 (8%) patients.Conclusions: In more than 80% of the patients with both documented iAT and rAT, P-wave morphology of iAT and rAT was quite similar. This suggested that complete abolition of iAT during AF ablation procedure would be mandatory in terms of reduction of AT recurrence during post-ablation follow-up.