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Clinically silent lesions on cerebral magnet resonance imaging have been found in larger numbers after pulmonary vein isolation (PVI) especially with phased radio frequency (pRF) using all ten electrodes. However, the neuropsychological effects of cerebral microembolism during the procedure remain unclear and data regarding this issue so far are inconsistent. Between August 2011 and June 2012, 76 patients undergoing their first PVI were randomized to ablation with either phased (40) or irrigated (36) radio frequency (iRF). A comprehensive neuropsychological test battery was performed the day before and after PVI as well as 6 months after ablation. The occurrence of cerebral microemboli during the procedure was performed via a transcranial Doppler ultrasound device. PVI using pRF was associated with increased number of microembolic signals (MES) compared to iRF (1530.0 ± 979.8 vs. 645.7 ± 448.7; p

Aims Phased radiofrequency (RF) ablation for atrial fibrillation is associated with an increased number of silent cerebral lesions on magnetic resonance imaging and cerebral microembolic signals (MESs) on transcranial Doppler ultrasound imaging compared with irrigated RF. The increased rate of embolic events may be due to a specific electrical interference of ablation electrodes attributed to the catheter design. The purpose of this study was to elucidate the effect of deactivating the culprit electrodes on cerebral MESs. Methods and results Twenty-nine consecutive patients (60 ± 11 years, 10 female) underwent their first pulmonary vein isolation using phased RF energy. Electrode pairs 1 or 5 were deactivated to avoid electrical interference between electrodes 1 and 10 (‘modified’). Detection of MESs by transcranial Doppler ultrasound was performed throughout the procedure to assess cerebral microembolism. Results were compared with the numbers of MESs in 31 patients ablated using all available electrodes (‘conventional’) and to 30 patients undergoing irrigated RF ablation of a previous randomized study. Ablation with ‘modified’ phased RF was associated with a marked decrease in MESs when compared with ‘conventional’ phased RF (566 ± 332 vs. 1530 ± 980; P < 0.001). This difference was mainly triggered by the reduction of MES during delivery of phased RF energy, resulting in MES numbers comparable to irrigated RF ablation (646 ± 449; P = 0.7). Total procedure duration as well as time of RF delivery was comparable between phased RF groups. Both times, however, were significantly shorter compared with the irrigated RF group (123 ± 28 vs. 195 ± 38; 15 ± 4 vs. 30 ± 9; P < 0.001, respectively). Conclusion Pulmonary vein isolation with ‘modified’ phased RF is associated with a decreased number of cerebral microembolism especially during the delivery of ablation impulses, supporting the significance of electrical interference between ablation electrodes 1 and 10. Deactivation of electrode pairs 1 or 5 might increase the safety of this approach without an increase in procedure duration or RF delivery time.

The traditional gout medication colchicine has been reported to effectively prevent atrial fibrillation recurrence after atrial fibrillation ablation or cardiac surgery in a few clinical trials. Severe adverse events have not yet been reported. The aim of the present study was to assess possible direct electrophysiological effects in an experimental whole-heart model. Ten rabbit hearts were isolated and Langendorff-perfused. Thereafter, colchicine was administered in two concentrations (1 and 3 μM). Eight endo- and epicardial monophasic action potentials and a 12-lead ECG showed a stable QT interval and action potential duration during colchicine infusion. Furthermore, there was no significant increase in dispersion of repolarization. However, colchicine induced a dose-dependent significant decrease of effective refractory period (ERP; 1 μM: -19 ms, 3 μM: -22 ms; p < 0.05). In the present study, acute infusion of colchicine in isolated rabbit hearts resulted in a reduction of ERP in the presence of a stable myocardial repolarization. This led to a significantly elevated inducibility of ventricular fibrillation. In 4 of 10 hearts, incessant ventricular fibrillation occurred. These results suggest a pro-arrhythmic or toxic effect of colchicine and underline that further clinical studies on potential adverse effects should be conducted before the drug can be recommended for routine use after atrial fibrillation ablation.

Background A post hoc analysis of the PALLAS trial suggested possible interactions of dronedarone and digitalis glycosides. The aim of the present study was to compare the effects dronedarone or amiodarone in combination with digitalis glycosides. Methods and results Eleven female rabbits underwent chronic oral treatment with amiodarone (50mg/kg/d for 6weeks). Ten rabbits were treated with dronedarone (50mg/kg/d for 6weeks). Ten rabbits were used as controls. Hearts were isolated and Langendorff-perfused. Monophasic action potentials and ECG showed a moderate prolongation of QT interval and action potential duration (APD). Both drugs also increased effective refractory period. Additional application of ouabain (0.2μM) resulted in a significant decrease of QT interval, APD, and ERP in all groups. Ventricular arrhythmias were induced by programmed ventricular stimulation and aggressive burst stimulation. Reproducible occurrence was defined as occurrence of at least 3 episodes. Under baseline conditions in control hearts, ventricular fibrillation (VF) was inducible in 1 of 10 hearts (7 episodes). After the application of 0.2μM ouabain, 4 of 10 control hearts were inducible (24 episodes). One of 10 dronedarone-pretreated hearts (3 episodes) and 2 of 11 amiodarone-pretreated hearts (6 episodes) showed VF before ouabain infusion. After the application of 0.2μM ouabain, 7 of 10 dronedarone-pretreated hearts were inducible (73 episodes). By contrast, only 4 of 11 amiodarone-pretreated hearts (13 episodes) showed VF. Conclusion In the present study, additional treatment with ouabain resulted in an increased ventricular vulnerability in al study groups. Of note, chronically dronedarone-pretreated hearts were significantly more vulnerable than amiodarone-pretreated hearts.

Objective We had the objective to determine the impact of clinical parameters and anticoagulation status on cerebral microembolic signals (MES) during pulmonary vein isolation (PVI) for atrial fibrillation (AF). Background Thromboembolism and stroke are the most feared complications of PVI. MES can help to evaluate embolic burden. It is unknown whether clinical parameters have an impact on embolic risk during PVI. Methods In this retrospective analysis we investigated the impact of clinical parameters, including the CHADS2- and CHA2DS2-VASc-score, pulmonary vein variants and echocardiographic parameters on MES rates in patients that underwent PVI using three different ablation approaches (radiofrequency ablation (iRF), pulmonary vein ablation catheter (PVAC) with deactivated electrode pair 1 or 5 (PVAC-red) or PVAC without deactivation (PVAC-all). Results 118 AF patients (61±12 years) were included between 2011 and 2013 (Median: 489 MES during PVI). Patients were more likely to have more MES (within 4th quartile) with the PVAC-all approach (60.7% vs. 25.0% (iRF) vs. 14.3% (PVAC-red) respectively (p

Aims The second-generation multi-electrode-phased radiofrequency pulmonary vein ablation catheter (PVAC GOLD®) was redesigned with the intent to improve its safety and efficacy. Methods and results Using a prospectively designed single-centre database, we retrospectively analysed 128 consecutive patients (102 paroxysmal and 43 female) who underwent their first pulmonary vein isolation with the PVAC GOLD®. The analysis focused on procedural data as well as in-hospital complications. Baseline characteristics of the patient collective were as follows: mean age 57.9 years, mean CHA2DS2-VASC was 1.73 ± 1.30; structural heart disease was present in seven patients. The PVAC GOLD® exhibited procedure durations of 123.1 min ± 27.9, duration of energy delivery was 18.3 min ± 11.4, and fluoroscopy duration was 16.0 min ± 7.7. The redesigned catheter shows major complication [major bleeding, transitory ischaemic attack (TIA), and pericardial tamponade] rates of 2.3% ( n = 3). The overall rate of adverse events was 5.4% ( n = 7). Bleeding complications were observed in three patients (2.3%), in particular there were two cases (1.6%) of minor bleeding and one case (0.8%) of major bleeding. Two patients suffered pericardial effusion, but there was no need for pericardiocentesis. Besides one TIA, there was no other thrombo-embolic event. Furthermore, one case of post-procedural fever was observed. No deaths, stroke, or haemorrhagic shock occurred. Of the 510 pulmonary veins, 508 could be reached with the PVAC GOLD® device using a non-steerable long sheath. Conclusion The PVAC GOLD® seems to have an acceptable safety profile. The handling is comparable with the previous generation PVAC®.