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IntroductionContinuous progress in atrial fibrillation (AF) ablation techniques has led to an increasing number of procedures with improved outcome. However, about 30–50% of patients still experience recurrences within 1 year after their ablation. Comprehensive translational research approaches integrated in clinical care pathways may improve our understanding of the complex pathophysiology of AF and improve patient selection for AF ablation.ObjectivesWithin the “IntenSive mOlecular and eLectropathological chAracterization of patienTs undergoIng atrial fibrillatiOn ablatioN” (ISOLATION) study, we aim to identify predictors of successful AF ablation in the following domains: (1) clinical factors, (2) AF patterns, (3) anatomical characteristics, (4) electrophysiological characteristics, (5) circulating biomarkers, and (6) genetic background. Herein, the design of the ISOLATION study and the integration of all study procedures into a standardized pathway for patients undergoing AF ablation are described.MethodsISOLATION (NCT04342312) is a two-center prospective cohort study including 650 patients undergoing AF ablation. Clinical characteristics and routine clinical test results will be collected, as well as results from the following additional diagnostics: determination of body composition, pre-procedural rhythm monitoring, extended surface electrocardiogram, biomarker testing, genetic analysis, and questionnaires. A multimodality model including a combination of established predictors and novel techniques will be developed to predict ablation success.DiscussionIn this study, several domains will be examined to identify predictors of successful AF ablation. The results may be used to improve patient selection for invasive AF management and to tailor treatment decisions to individual patients.

OBJECTIVES: Minimally invasive thoracoscopic epicardial pulmonary vein isolation (MIPI) has an important role in the surgical treatment of atrial fibrillation (AF). However, the management of recurrent atrial arrhythmias after MIPI and long-term success rate of catheter ablation have not been well studied. METHODS: Electrophysiological study was performed in 23 patients, 378 ± 282 days after MIPI surgery, because of recurrent symptomatic atrial arrhythmias. RESULTS: A total of 20 patients presented with paroxysmal and persistent AF, 2 patients had a combination of AF and atrial tachycardia (AT) and 1 patient had a combination of AF and atrial flutter. All patients showed pulmonary vein (PV) reconnection. ATs were micro-re-entry PV-related ATs and atrial flutter was cavotricuspid isthmus dependent. Eighteen of 23 patients (78.3%) were free of atrial arrhythmias after one catheter ablation procedure at a mean follow-up of 50 ± 16 months. Three patients underwent a second ablation procedure for recurrent AF and macro-re-entry left atrial flutter. Eventually 20 of 23 patients (87%) remained free of atrial arrhythmias after a mean of 1.1 ± 0.3 ablation procedures. CONCLUSIONS: Catheter ablation of recurrent atrial arrhythmias following MIPI for paroxysmal and persistent AF is a feasible and effective treatment with a good long-term success rate. Reconnection of PVs accounts for most recurrences. [ABSTRACT FROM AUTHOR]

Drug-induced QT prolongation increases the risk of Torsade de Pointes (TdP). Drug-induced QT prolongation is a complex and unpredictable system due to many uncertainties. Risk factors such as electrolyte disturbances, heart failure and genetics play an important role in estimating the effect on QT prolongation. Moreover, the degree of QT prolongation is not always directly related to the risk of TdP and the assessment of the QT-interval is variable depending on the type and timing of QT measurement. Therefore, the variation in QT measurement may be larger than the effect of certain drugs on the QT interval. Because of the potentially lethal risk, several measures are undertaken to reduce the risk of QT prolongation and TdP, while their effect and proportionality are unclear. We suggest we should be less stringent in certain settings when risk of TdP is extremely low given the limited availability of our resources.

Aims: Focal atrial tachycardia successfully ablated from the non-coronary cusp (NCC) is rare. Our aim was to describe the characteristics of mapping and ablation therapy of NCC focal atrial tachycardias and to provide a comprehensive review of the literature., Methods and Results: Seven patients (age 40 ± 9 years) with symptomatic, drug-refractory atrial tachycardia were referred for electrophysiological study. Extensive right and left atrial mapping revealed atrial tachycardia near His in all patients but either failed to identify a successful ablation site or radiofrequency applications only resulted in temporary termination of the tachycardia. Mapping and ablation of the NCC were performed retrogradely via the right femoral artery. Mapping of the NCC demonstrated earliest atrial activation during atrial tachycardia 38 ± 14 ms (ranging 17-56 ms) before the onset of the P-wave. Earliest atrial activation in the NCC was earlier than earliest activation in the right atrium and left atrium in all patients. The P-wave morphology was predominantly negative in the inferior leads and biphasic in leads V1 and V2. The tachycardia was successfully terminated by radiofrequency application in 10 ± 6 s (2-16 s), without complications. All patients were free of symptoms during a follow-up of 19 ± 9 months. Literature search revealed 18 reports (91 patients) describing NCC focal atrial tachycardia, with 99% long-term ablation success with a 1% complication rate., Conclusion: Symptomatic focal atrial tachycardia near His may originate from the NCC and can be treated safely and effectively with radiofrequency ablation., (Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2014. For permissions please email: journals.permissions@oup.com.)