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We present the case of a patient who developed regular, narrow QRS tachycardia after ablation for long-standing persistent atrial fibrillation. During the electrophysiological study, this tachycardia was diagnosed as macroreentrant atrial tachycardia circulating around the mitral annulus. Catheter ablation was performed to treat the tachycardia by targeting the linear region between the annulus and the left inferior pulmonary vein. Although linear radiofrequency application along the mitral isthmus (MI) line resulted in the termination of this tachycardia, a unidirectional conduction block was observed through the MI. Bidirectional conduction block was subsequently achieved by delivering supplemental radiofrequency energies at the gap on the MI.

Background: Although warfarin is potentiated by omeprazole through interference of the cytochrome P450 system, little is known in other proton pump inhibitors (PPIs). We evaluated the interactions between warfarin and lansoprazole/sodium rabeprazole. Methods: This retrospective study consisted of 161 atrial fibrillation (AF) patients who underwent catheter ablation of AF. Optimal anticoagulation treatment by warfarin was performed in all patients without taking PPIs prior to procedure. Following ablation, 15 mg of lansoprazole or 10 mg of sodium rabeprazole was administered in patients presenting Gastrointestinal discomfort. We investigated the dose of warfarin required to maintain optimal prothrombin time international normalized ratio (PT-INR) before the procedure and at 3 months after administration of PPIs. Results: Lansoprazole and sodium rabeprazole were administered in 62 and 63 patients with gastroesophagitis symptom, respectively. There were no significant differences in dose of warfarin between before and after taking lansoprazole (4.0±1.2 mg/day vs. 4.1±1.2 mg/day, p=NS)/rabeprazole (3.8±1.0 mg/day vs. 3.8±1.1 mg/day, p=NS). Additionally, no differences were observed in the value of PT-INR between before and after taking PPIs in patients with lansoprazole (1.9±0.3 vs. 2.0±0.5, P=NS) and rabeprazole (2.1±0.4 vs. 2.1±0.5, P=NS). Conclusion: Lansoprazole and rabeprazole could be safely used in patients with anticoagulant treatment by warfarin.

Background: The inducibility of atrial fibrillation (AF) by Isoproterenol (ISP) and adenosine triphosphate (ATP) has not been sufficiently investigated. Methods: This study consisted of consecutive 69 paroxysmal AF patients who underwent the pulmonary vein antrum isolation (PVAI). During sinus rhythm, the AF inducibility by venous injection of either ATP (20–40 mg) or ISP (4–8 µg) or concurrent administration both of ISP and ATP was examined before and after the PVAI. Results: In total, AF was induced from 36 sites in 50.7% (35/69) of patients, triggered by firing from PVs, superior vena cava in 34 and one patient, respectively. AF was more frequently induced by concurrent administration both of ISP and ATP compared to injection of solo-ATP or solo-ISP (43.5% (30/69) vs. 23.2% (16/69) vs. 21.7% (15/69), P=0.007). Of 30 patients with AF induction by concurrent administration both of ATP and ISP, AF was not induced by solo-ATP or solo-ISP only in 14 (46.7%) patients. Following ablation, no AF could be induced by any administration of ISP and ATP. Conclusion: Solo use of ATP or ISP was insufficient to induce AF. Concurrent administration both of ISP and ATP is useful for induction of AF in patients with paroxysmal AF.

Aims: The relative efficacy of open irrigated tip catheters compared with conventional non-irrigated catheters for catheter ablation of atrial fibrillation (AF) is unknown. Methods: A total of 501 consecutive AF patients (age: 55 years, 453 males paroxysmal AF: 264 and persistent AF: 243) was included in the present study study. Catheter ablation was performed with using open-irrigated and non-irrigated 8 mm catheters in 265 and 236 AF patients, respectively. Pulmonary veins (PVs) were isolated in all patients. The supplemental ablation, involving the electrogram-based ablation (n=148) or/and the linear ablation (n=134), was performed in persistent AF. Results: The success rates of PV isolation, electrogram-based ablation (termination of AF), linear ablation (bi-directional block) did not differ between 2 groups. The duration and amount of radiofrequency energy delivery for PV isolation (1252±656 vs. 2171±1128 seconds, P

Background: The dissociated activities (DAs) indicates arrhythmogenicity of the isolated PV after the pulmonary vein isolation (PVI) for atrial fibrillation (AF). We investigated its impact on AF recurrence after the PVI. Methods: The subjects were 84 paroxysmal AF patients (age: 55±9, 71 males) who had recurrence after PVI and underwent the repeat procedure. All patients were divided into two groups regarding to the presence/absence of DAs during the first procedure (group A: DAs in ≥1PV, group B: no DA). Results: Group A and B consisted of 62 and 22 patients, respectively. In the repeat session, the number of reconnected PVs was similar between the two groups (203/246 (83%) PVs vs. 69/87 (79%) PVs, P=0.61). The mean age was significantly higher (60±8 vs. 54±11 years, P

Backgrounds: Recent evidence demonstrated that serum free thyroxine (FT4) concentration was independently associated with the development of atrial fibrillation (AF), even in euthyroid persons with TSH levels in the normal range. We examined the impact of thyroid function on the risk of recurrent and newly developed atrial tachyarrythmias after catheter ablation for AF. Methods: This study included 156 consecutive patients with paroxysmal AF who underwent initial pulmonary vein antral isolation with elimination of dormant conduction induced by isoproterenol and adenotriphosphate injection. Patients with prior or current thyroid dysfunction were excluded. We examined the occurrence of documented recurrent or newly developed atrial tachyarrhythmia after the ablation. Results: After a mean follow-up of 27 months, 12.2% (19/156) of the studied subjects had AF recurrence. Although the AF recurrence rates of the highest FT4 quartile tended to be higher, there was no significant difference in recurrence rates among those quartiles. Patients with newly developed atrial tachycardia/flutter had significantly higher serum FT4 level and lower serum thyroid-stimulating hormone. The higher FT4 level was significantly associated with newly documented atrial tachycardia/flutter. Conclusions: Patients with high-normal thyroid function were not at an increased risk of AF recurrence but associated with newly developed atrial tachycardia/flutter after catheter ablation.

Although catheter ablation has been demonstrated as the potentially curative treatment for atrial fibrillation, radiofrequency energy delivery of the posterior left atrium could result in the thermal injury to the esophagus. Thus, the anatomical relationship between the left atrium (LA) and esophagus is crucial for the prevention of the injury of the esophagus during LA ablation. The position of the esophagus can be identified by integration of three dimensional electroanatomical mapping system with the computed tomography (CT). The esophagus, however, may shift even during the ablation procedure. In addition, the integration of the CT image and 3-dimensional mapping system could be difficult or even inaccurate due to the difference of the body posture, heart rhythm and hydration state. On the other hand, the three-dimensional rotational atriography (3DATG) is performed during the procedure. Furthermore, the 3DATG with the direct injection of contrast medium into the LA can be performed without the postural change. In the present series, catheter ablation of AF was performed with a use of the 3DATG by the direct LA administration and simultaneous esophagography. We examined the usefulness and safety of the 3DATG to evaluate the anatomical relationship between the LA and esophagus through the AF ablation procedure.

Purpose Although catheter ablation targeting the pulmonary vein (PV) is a well-known therapy for patients with paroxysmal atrial fibrillation (PAF), ectopic firings from the superior vena cava (SVC) can initiate PAF. The purpose of this study was to investigate predictors of SVC firing.

Purpose: Cerebral thromboembolism is a serious complication related to the catheter ablation of atrial fibrillation (AF). We investigated the procedural thromboembolism in patients with AF underwent catheter ablation. Methods: A total of consecutive 174 AF patients who underwent ablation by using an open irrigated ablation catheter was included in the present study. During all procedure, activated coagulation time was maintained 300–350 seconds. Brain diffusion-weighted magnetic imaging (DWI) was performed 2 day after the procedure in all subjects. Results: Cerebral thromboembolism was revealed by the DWI in 23.0% (40/174) of patients following the procedure. All patients with thromboembolism were asymptomatic. In univariate analysis, age was significantly higher (59.4±8.9 vs. 54.8±9.6 years, P=0.009), the left atrium was larger (41.6±5.7 vs. 38.7±5.5 mm, P=0.004) and history of AF was longer (8.4±6.8 vs. 5.3±4.3 years, P=0.0008) in patients with the thromboembolism than those without. In multivariate analysis, history of AF was the only independent predictor of procedure related thromboembolism in patients with AF ablation (odds ratio: 1.13, P=0.01). Conclusion: Procedure related silent thromboembolism was observed in a quarter of patients who underwent AF ablation with an open irrigated ablation catheter. The history of AF was an independent predictor of thromboembolism during catheter ablation of AF.

The case of a patient with narrow QRS tachycardia is herein presented. During an electrophysiological study, this tachycardia was diagnosed as a focal atrial tachycardia with a high sensitivity to adenosine-5′-triphosphate (2 mg), and originating from near the His-bundle region. We could not ablate the earliest activation site in the right atrium because of the simultaneous recording of the His potential. The radiofrequency applications in the right atrium around the earliest activation site failed to terminate the tachycardia. Subsequent attempt of radiofrequency application in the non-coronary aortic cusp, where the earliest atrial activation without His potential was obtained, successfully eliminated the tachycardia without any atrioventricular nodal injury.