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Background Anatomically guided pulmonary vein isolation (PVI) is the cornerstone of atrial fibrillation (AF) ablation. However, the position where to confirm electrical isolation is ill-defined. The aim of the current study was to quantify the relationship between the anatomical and electrical definition of the pulmonary vein ostium. Methods We analyzed 20 patients with paroxysmal AF undergoing PVI using radiofrequency energy and an electroanatomical mapping system. The anatomical ostium was defined based on the geometry obtained from preprocedural magnetic resonance imaging and computed tomography. The electrical ostium was defined at the position with a far-field atrial signal preceding a sharp pulmonary vein (PV) signal without any isoelectric interval in between. Results The electrically defined ostia were 8.4 ± 4.7 mm more distal in the PV compared to the anatomically defined ostia. The distances varied considerably between the four PVs and were 10.5 ± 6.5 mm, 7.4 ± 4.3 mm, 5.3 ± 4.0 mm, and 8.3 ± 3.4 mm for the left superior, left inferior, right superior, and right inferior PVs, respectively (P = 0.009). Conclusions The position of the electrical and anatomical ostium differs markedly. The site of the electrical ostium is variable within the PV but always more distal in the PV compared to the site of the anatomical ostium. [ABSTRACT FROM AUTHOR]

Background Many patients receiving an implantable cardioverter-defibrillator (ICD) also have atrial fibrillation (AF). Shock testing during ICD implantation carries a potential risk of cardioversion to sinus rhythm (SR) and thrombembolic events. We aimed to analyze the recurrence of AF after cardioversion to SR during ICD shock testing. Methods A total of 555 consecutive patients referred to a tertiary hospital in Switzerland for ICD implantation or generator exchange between 02/2002 and 03/2010 were screened for AF. Fifty-seven patients who were in AF at the time of ICD shock testing were included. Results Forty-four patients (77%) were successfully cardioverted from AF to SR. Type of AF (persistent, not permanent 64 vs 31% of cardioverted patients) was the only predictor. Thirty-nine patients (89%) experienced a recurrence of AF/atrial flutter after a median of 54 days (interquartile range 35-251 days). The only predictor for recurrence of AF was previous AF declared as permanent. No ischemic stroke occurred during hospitalization for the procedure. Conclusions For patients in AF undergoing shock testing at the time of ICD implant, there is a high chance of cardioversion from AF to SR, but there is also a high risk of early recurrence. Decisions regarding long-term anticoagulation should not be based on the heart rhythm immediately following shock testing. [ABSTRACT FROM AUTHOR]

Background To compare the feasibility and efficiency of atrioventricular junction (AVJ) ablation and device implantation in patients with drug-refractory atrial fibrillation using three different approaches. Methods Sixty-nine patients (57% male; age 72 ± 10; ejection fraction 45 ± 15%) undergoing device implantation and AVJ ablation were retrospectively studied at a tertiary referral center. In 20 patients (29%) AVJ ablation was performed via the femoral vein immediately following device implantation (group 1), whereas 33 patients (48%) underwent a staged procedure with AVJ ablation via the femoral vein >3 weeks after device implantation (group 2). In a third group of 16 patients (23%), AVJ ablation was performed during device implantation through the pocket using the same axillary vein access site (group 3). The main outcome measures were: procedure time, fluoroscopy time, laboratory occupancy time, and success rate. Results There was a significant difference in procedure time (118 ± 45 minutes. in group 1, 133 ± 32 minutes in group 2, and 87 ± 26 minutes in group 3, P < 0.001) and the laboratory occupancy time (175 ± 48 minutes in group 1, 200 ± 32 minutes in group 2, and 121 ± 27 minutes in group 3, P < 0.001). There was no difference in fluoroscopy time (group 1: 20 ± 15 minutes, group 2: 27 ± 22 minutes, and group 3: 24 ± 9 minutes P = 0.4). The procedure was successfully completed in all patients, but cross-over to a femoral approach was required in one patient in group 3. Conclusion The alternative approach of AVJ ablation during permanent pacemaker implantation from the same axillary vein access site is feasible and more efficient compared to the femoral approach. [ABSTRACT FROM AUTHOR]

Transvenous atrial defibrillation with multiple atrial lead systems has been shown to be effective in models without the potential for ventricular arrhythmias. The specific aim of this study was to evaluate the efficacy and safety of transvenous single lead atrial defibrillation in a canine model of ischemic cardiomyopathy. Ten dogs had ischecnic cardioinyopathy induced by repeated intrncoronary microsphere injections. The mean LV ejection fraction decreased from 71% ± 9% to 38% 24% (P = 0.003). Spontaneous atrial fibrillation (Af) developed in four dogs. and in six AF was induced electrically. A trial defibrillation thresholds (ADFTs) were determined with synchtonous low energy shocks using a transvenous tripolar lead with two defibrillation coils (right ventricle, superior vena cava) and an integrated sensing lead (RV coil vs electrode tip). The ADFTs derived by logistic regression were compared at 50% and 90% probability of success (ED50, ED90): ED50 was 2.4 ± 1.71 and 2.9 ± 2.1 J, respectively, for 5- and I 0-ms monophasic shocks, and 1.8 .1 0.9 Jand 2.1 ± l.3 J, respcctivctv, for 5- and 10-ms biphasic shocks. Immediately after 3 of 2,179 (0.1%) synchronized shocks, ventricular fibrillation (VF) developed. VF was induced in 3 of 1,062 (0.3%) shocks with integrated sensing (1W coil vs electrode tip) compared to 0 of 1,117 shocks when a separate bipolar RI! sensing electrode was used for synchronization. In our canine model of ischemic cardiomyopathy. low energy atrial defibrillation via a transvenous single lead system was highly effective. However, there was a small but definite risk of VF induction, which seemed to be greater when an integrated as opposed to a true bipolar RV sensing was used. [ABSTRACT FROM AUTHOR]

Ectopic beats originating from the superior vena cava (SVC) may initiate atrial fibrillation. This report describes a patient undergoing radiofrequency catheter ablation for electrical isolation of the SVC resulting in SVC stenosis. Noncircumferential lesion sets for SVC isolation to reduce ablation times may be preferred. (PACE 2010; e36–e38) [ABSTRACT FROM AUTHOR]