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Aims Non-invasive electrocardiogram (ECG) mapping allows the activation of the entire atrial epicardium to be recorded simultaneously, potentially identifying mechanisms critical for atrial fibrillation (AF) persistence. We sought to evaluate the utility of ECG mapping as a practical tool prior to ablation of persistent AF (PsAF) in centres with no practical experience of the system. Methods and results A total of 118 patients with continuous AF duration

Aims Overlap syndromes of long QT 3 syndrome (LQT3) and the Brugada syndrome (BrS) have been reported. Identification of patients with an overlapping phenotype is crucial before initiation of Class I antiarrhythmic drugs for LQT3. Aim of the present study was to elucidate the yield of ajmaline challenge in unmasking the Brugada phenotype in patients with LQT3 caused by the most common mutation, SCN5A-E1784K. Methods and results Consecutive families in tertiary referral centres diagnosed with LQT3 caused by SCN5A-E1784K were included in the study. Besides routine clinical work-up, ajmaline challenge was performed after informed consent. A total of 23 subjects (11 female, mean age 27 ± 14 years) from 4 unrelated families with a family history of sudden cardiac death and familial diagnosis of the SCN5A-E1784K mutation underwent ajmaline challenge and genetic testing. Sixteen subjects (9 female) were found to be heterozygous carriers of SCN5A-E1784K. Ajmaline challenge was positive in 12 out of the 16 (75%) mutation carriers, but negative in all non-carriers. Following ajmaline, a significant shortening of the rate-corrected JT (JTc) interval was observed in mutation carriers. The baseline JTc interval was significantly longer in mutation carriers with a positive ajmaline challenge compared with those with a negative one. Conclusion Overlap of LQT3 and BrS in patients carrying the most common mutation is high. Therefore, ajmaline challenge represents an important step to rule out potential BrS overlap in these patients before starting sodium channel blockers for the beneficial effect of QT shortening in LQT3.

Aims Patients can expect a cure from atrial fibrillation (AF) with ablation. Procedural safety and success depend on patient comfort, compliance, and immobility. This is difficult to achieve with benzodiazepine and opiate boluses that are the mainstay of current practice. We sought to determine the safety and efficacy of propofol infusion sedation administered to patients without assisted ventilation for AF ablation. Methods and results Procedural data from 1000 consecutive patients undergoing AF ablation were analysed. Sedation with 2% propofol was used in all procedures without assisted ventilation and was administered, monitored, and controlled by electrophysiologists. Primary outcome measures were adverse sedative affects including (i) respiratory depression (SpO2 20 s) and (ii) persistent hypotension [systolic blood pressure (SBP)

Pulmonary veins (PVs) are the predominant sources of paroxysmal atrial fibrillation (AF), and electrical PV isolation has become an established interventional treatment for patients suffering from AF. There are a few cases describing PV tachycardias; however, mechanisms of PV arrhythmogenicity resulting in PV tachycardias remain incompletely understood. We report on a patient who underwent PV isolation for paroxysmal AF, in whom a persistent PV tachycardia was observed within an isolated vein. This tachycardia was stable in nature and different pacing manoeuvres revealed electrophysiological features consistent with reentry (Lasso displaying the entire tachycardia cycle length, concealed entrainment, overdrive termination, and induction by programmed stimulation) as the underlying mechanism.

Aims To evaluate the contribution of the posterior left atrium (LA) to chronic atrial fibrillation (AF). Methods and results Twenty-seven patients with chronic-AF were studied. After pulmonary vein (PV) isolation, the posterior-LA was isolated by ablation joining the right- and left-PVs using an irrigated-tip catheter. Isolation was demonstrated by absent/dissociated posterior-LA activity and the inability to pace the region. Ablation impact was determined by the effect on cycle length (CL) and AF termination. Posterior-LA isolation was achieved using 35 ± 12 min of radiofrequency with total fluoroscopic and procedural durations of 64 ± 16 and 199 ± 46 min, resulting in abolition of electrograms ( n = 21) or autonomous activity ( n = 6; CL 820 ± 343 ms). AFCL increased from 156 ± 28 ms to 162 ± 27 ms with PV-isolation and to 175 ± 32 ms by posterior-LA exclusion ( P < 0.0001). AF persisted in all after PV-isolation and terminated in 5 (19%) during posterior-LA-isolation. After 10 ± 6 months, 12 patients developed atrial tachycardia (four) or AF (eight); four underwent repeat posterior-LA-isolation, while the others required additional ablation/antiarrhythmics. After 21 ± 5 months, 17 (63%) were in sinus rhythm following posterior-LA-isolation. Conclusion This study demonstrates the feasibility of complete posterior-LA exclusion by catheter ablation. This strategy results in maintenance of sinus rhythm in 63% at ∼2 years follow-up.

Aims To investigate the effectiveness of additional substrate modification (SM) by left atrial (LA) linear lesions as compared with pulmonary vein isolation (PVI) alone in patients with persistent atrial fibrilla- tion (AF) in a prospective randomized study. Percutaneous PVI has evolved as an accepted treatment for paroxysmal AF but seemed to be less effective in patients with persistent AF. The benefit of PVI alone and additional linear lesions has not been validated in a randomized study so far. Methods and results Sixty-two patients with persistent AF (median duration 7, range 1-18 months) were randomly assigned to either PVI alone (n ¼ 30) or additional SM (n ¼ 32) consisting of a roof line connecting both left superior and right superior PV and LA isthmus ablation between left inferior PV and mitral annulus. Procedures including SM were performed using a three-dimensional mapping system (EnSite NavX TM , St Jude Medical, St Paul, MN, USA). Anti-arrhythmic drugs were discontinued within 8 weeks after ablation in both groups. Follow-up included daily trans-telephonic ECG transmitted irrespective of the patient's symptoms. PVI was successful in 98% of all targeted veins in both groups. Additional SM did not increase fluoroscopy time (72.1+ 18.7 vs. 72.9+ 17.3 min, P ¼ 0.92) because of the use of three-dimensional navigation in the PVI þ SM group. AF recurrences within the first 4 weeks following ablation were more common after PVI alone (77%) than additional SM (44%, P ¼ 0.002). After a follow-up time of 487 (429-570) days, only 20% of patients undergoing stand alone PVI remained in sinus rhythm when compared with 69% following PVI combined with SM (P ¼ 0.0001). Two patients assigned to PVI þ SM experienced procedure-related complications (cardiac tamponade and minor stroke) which resolved without sequelae. Conclusion PVI alone is insufficient in the treatment of persistent AF. However, additional left linear lesions increase the success rate significantly. Early AF-relapses are associated with a negative outcome after PVI alone but not following additional SM.

Aim Sub-threshold stimulation (STS) applied during atrioventricular nodal re-entrant tachycardia (AVNRT) of the common (slow–fast) type has been shown to effectively characterise target sites suitable for slow pathway (SP) ablation but has not been investigated in the setting of fast–slow and slow–slow variants. Methods and results Seventeen consecutive patients (52±16 years, 12 female) with sustained uncommon type AVNRT (fast–slow: \batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \(n=13\) \end{document}, slow–slow: \batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \(n=4\) \end{document}) were investigated. Mapping of the SP was started postero-septally close to the coronary sinus ostium and continued toward mid-septal sites, if required. Target sites for STS were selected according to established criteria including the recording of the earliest retrograde atrial activation during AVNRT. Long duration (5 s) constant current STS during AVNRT variants was performed in a stepwise manner (max 5 mA) at each site eligible for SP ablation until termination or capture occurred. Radiofrequency current (RFC) was delivered following successful STS termination of tachycardia (65 °C, 60 s) and exclusion of catheter dislodgement. Uncommon AVNRT with a mean cycle length of 405±70 ms was induced without spontaneous termination in all patients. Interruption of AVNRT variants due to selective STS-induced block of the retrograde (\batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \(n=12\) \end{document}) or anterograde (\batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \(n=2\) \end{document}) SP occurred without capture in 14/17 (82%) patients. This was exclusively observed at sites with successful subsequent RFC application. AVNRT was rendered non-inducible in all patients after a median of 1 (1–11) RFC pulses without complications. Conclusions Uncommon AVNRT can be interrupted by STS delivered at subsequently successful target sites for SP ablation in most patients (82%). The high positive and negative concordance between the effects of STS and following RFC application indicates that STS-mapping is also useful in the setting of AVNRT variants.

Although recommended by the current guidelines for the treatment of atrial fibrillation (AF),1,2 catheter ablation of long-standing persistent AF (herein referred to as chronic AF) still remains a challenge for the interventional electrophysiologist. Initial attempts at a successful treatment of chronic AF have concentrated on different lesion sets. In the past, we have learned that pulmonary vein (PV) isolation alone, irrespective of its extension in terms of isolated atrial tissue around the PVs, is not sufficient to achieve a considerable success rate and, therefore, is restricted to a very selected cohort of chronic AF patients.3,4 Thus, additional arrhythmogenic processes beyond the PVs have become evident in the pathophysiology of chronic AF. Based on the concept of the ‘multiple wavelet’ hypothesis and in an effort to replicate the results of the surgical treatment of AF, linear lesions were applied to the left atrium, alone or in addition to PV isolation. However, with bidirectionally blocked lines at the left atrial roof and the mitral isthmus,4 or even with complete electrical isolation of the posterior left atrium including the PVs,5 the success rates range between 60 and 70%. Since a significant number of patients did not benefit from a standardized lesion set, the new concept rather to tailor the ablation approach to the patients' individual chronic AF processes has been implemented by Haissaguerre and co-workers.6 This concept was based on the observation that chronic AF could occasionally be terminated by ablation. Thus, using the combination of different strategies, … *Corresponding author. Tel: +49 40 428034120, Fax: +49 40 428034125, Email: willems{at}uke.uni-hamburg.de

Introduction: Single procedure success rates of pulmonary vein isolation (PVI) in patients with paroxysmal atrial fibrillation (PAF) are still unsatisfactory. In patients with persistent AF adjunctive ablation of complex fractionated atrial electrograms (CFAE) is frequently used to improve outcome. We hypothesized that a subgroup of PAF-patients with sustained AF acutely after PVI might also benefit from additional CFAE-ablation. Methods: Overall 1032 consecutive patients received a first catheter ablation of strictly PAF between 08/2008-12/2012. In most patients AF was either not inducible or terminated during PVI. AF sustained after successful PVI in 61 patients (6%), who were randomized to either cardioversion (PVI-alone, n=30) or additional CFAE-ablation (PVI+CFAE, n=31). Primary endpoint was the reoccurrence of AF/AT. Results: Randomized patients had an AF-history of 62±8 months with max. episodes of 15±2 hours. Procedure-duration (126±6 vs 171±9 min), radiofrequency (RF) application- (44±3 vs 72±5 min) and fluoroscopy time (26±2 vs 40±2 min) were longer in PVI+CFAE (all p