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Objective: Uninterrupted oral warfarin strategy has become the standard protocol to prevent complications during catheter ablation (CA) for the treatment of atrial fibrillation (AF). However, little is known about the safety and efficacy of uninterrupted dabigatran therapy in patients undergoing CA for AF. Therefore, this study investigated the safety and efficacy of uninterrupted dabigatran therapy and compared the findings with those for uninterrupted warfarin therapy., Methods: Bleeding and thromboembolic events during the periprocedural period were evaluated in 363 consecutive patients who underwent CA for AF at Nagoya University Hospital, and received uninterrupted dabigatran (n=173) or uninterrupted warfarin (n=190) for periprocedural anticoagulation., Results: A total of 27 (7%) patients experienced either bleeding or thromboembolic complications. Major bleeding complications occurred in 2 (1%) patients in the dabigatran group (DG) and 2 (1%) patients in the warfarin group (WG). Eight (5%) patients in the DG and 9 (5%) patients in the WG experienced groin hematoma, a type of minor bleeding complication. Meanwhile, no patient in the DG and 1 (1%) in the WG developed cerebral ischemic stroke. Overall, there was no significant difference between the groups for any category. The activated partial thromboplastin time (APTT) independently predicted periprocedural complications in the DG., Conclusion: Uninterrupted dabigatran therapy in CA for AF thus may be a safe and effective anticoagulant therapy, and appears to be closely similar to continuous warfarin; however, it is essential to pay close attention to the APTT values when using dabigatran during CA.

Introduction: A difference in the lesion formation between open irrigated-tip (OITC) and non-irrigated 4-mm-tip catheters (NITC) may result in a difference in the dimension of the pulmonary vein (PV) ostia after PV isolation of atrial fibrillation (AF). This study evaluated the difference using intracardiac echocardiography (ICE) before and immediately after an extensive encircling PV isolation (EPVI) with an OITC and with an NITC., Methods and Results: We studied 100 consecutive patients (OITC group, 54; NITC group, 46) who received EPVI. Changes in the vessel, lumen, and wall thickness areas of the PVs were evaluated at the PV ostia by ICE. There were no significant differences in the baseline characteristics and acute success rate of the EPVI between the OITC and NITC groups. The energy delivered to achieve EPVI was higher in the OITC group than that in the NITC group (34,967 ± 13,222 J vs. 28,300 ± 10,614 J; p=0.01). After the ablation, the reduction in the vessel and lumen cross-sectional areas was significantly smaller in the OITC group than that in the NITC group (-9.05 ± 28.4 % vs. -21.2 ± 28.8 %, p<0.001; -8.76 % vs. -17.7 ± 26.9 %, p=0.003). The wall thickness area slightly decreased in the OITC group, but increased in the NITC group (-2.96 ± 38.4 % vs. 10.5 ± 76.6 %, p=0.591). During a median follow-up of 234 days, there was no significant difference in the AF recurrence after the initial ablation procedure between the two groups., Conclusion: Greater PV ostial narrowing occurred with the NITC than OITC immediately after the EPVI. PV ostial wall edema was noted with only the NITC. These findings suggested that an OITC might reduce any acute PV narrowing and wall edema as compared with an NITC.

Background: Radiofrequency catheter ablation (RFCA) is increasingly performed for the treatment of atrial fibrillation (AF), but it is problematic because the use of anti-arrhythmic agents is largely restricted in patients undergoing hemodialysis (HD) therapy. However, little is known about the long-term clinical outcomes of AF after RFCA in HD patients., Methods: Between 2002 and 2008, 16 HD patients (age: 63.8 ± 7.4 years, 75.0% men) underwent RFCA for AF at the Toyota Kosei Hospital. We investigated the long-term results and mortality of RFCA for AF in HD patients and compared them with those of 111 non-HD patients (age: 58.6 ± 10.0 years, 78.3% male) who received the same procedures., Results: During the follow-up (64.3 ± 25.4 months in HD patients, 70.5 ± 20.2 months in non-HD patients) after the initial RFCA procedure, sinus rhythm was restored in 4 HD patients (25%) and in 45 non-HD patients (40.5%). Multiple procedures were performed in 12 HD patients and in 57 non-HD patients. After the final procedure, 13 HD patients (81.3%) and 92 non-HD patients (82.9%) were free of atrial arrhythmia and symptoms. Of importance, Kaplan-Meier analysis did not demonstrate any significant differences in the atrial arrhythmia-free rate after the last procedure between HD patients and the control group matched after propensity-score analysis despite higher all-cause mortality in HD patients than in non-HD patients., Conclusions: During 5-years of follow-up, the use of multiple RFCA procedures for AF in patients undergoing HD was favorable, whereas the use of a single procedure was disappointing. Multiple RFCA procedures can be an efficient approach to the treatment of AF in HD patients.

Background: Although several ECG algorithms have been proposed for differentiating the origins of outflow tract ventricular arrhythmia (OT-VA), their accuracy still is limited in cases with cardiac rotation., Objective: The purpose of this study was to assess whether a novel "cardiac rotation-corrected" transitional zone (TZ) index would be a useful marker for differentiating right ventricular outflow tract (RVOT) origin from aortic sinus cusp (ASC) origin., Methods: Surface ECGs of OT-VAs with left bundle branch block morphology and inferior axis in 112 patients who were successfully ablated in the RVOT (n = 87) or the ASC (n = 25) were analyzed. The TZ index was defined according to the site of R-wave transition of sinus beats and OT-VAs., Results: The TZ index was significantly lower in the ASC origin than in the RVOT origin (-1.2 ± 0.9 vs 0.3 ± 0.7, P <.0001). A cutoff value of the TZ index <0 predicted the ASC origin with 88% sensitivity and 82% specificity. The previously reported R-wave duration index ≥ 50% had a high specificity of 85% but a low sensitivity of 44%, and R/S-wave amplitude index ≥ 30% had 68% sensitivity and 79% specificity. The area under the curve by receiver operating characteristic curve analysis was 0.90 for the TZ index, which was significantly higher than the R-wave duration index and R/S-wave amplitude index of 0.74 and 0.76, respectively., Conclusion: This novel TZ index can be a more useful marker for differentiating RVOT origin from ASC origin., (Copyright © 2011 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)

Aims: This study investigated the potential association between homocysteine levels and cardiovascular events or atrial fibrillation (AF) recurrence following radiofrequency catheter ablation (RFCA) in patients with AF., Methods and Results: Blood samples were obtained prior to the RFCA procedure. Levels of homocysteine and carboxy-terminal telopeptide of collagen type I (CITP), a collagen type I degradation marker, were measured in 96 patients receiving RFCA; 62 paroxysmal or persistent AF patients and 34 paroxysmal supra-ventricular tachycardia patients. Patients were followed up for 2.1 +/- 1.5 years. Plasma homocysteine levels were significantly higher in patients with persistent AF (P < 0.05) compared with levels in paroxysmal AF and control patients. Homocysteine levels also positively correlated with left atrial dimension (LAD) (P < 0.01) and CITP levels (P < 0.001). While no significant correlation was found between basal homocysteine levels and recurrent AF after RFCA in AF patients, patients in the high homocysteine group exhibited a significantly higher rate of cardiovascular events without AF recurrence compared with those in the low homocysteine group (P < 0.05)., Conclusion: High homocysteine levels are associated with the presence of persistent AF, which is accompanied by increased CITP levels and LAD. Also confirmed is the role of homocysteine as a risk factor for the pathogenesis of cardiovascular events after RFCA in AF patients. Measurement of homocysteine level may provide useful information for the managing cardiovascular risk in patients with AF.