Reliable prediction of very late recurrence of atrial fibrillation (VLRAF) occuring >12 months after catheter ablation (CA) in apparently "cured" patients could optimize long-term follow-up and modify decision-making regarding the discontinuation of oral anticoagulant therapy. In a single-centre cohort of consecutive patients post radiofrequency AFCA, we retrospectively derived a novel score for VLRAF prediction. Of 133 consecutive post AFCA patients (mean age 56.9 ± 11.8 years, 63.9% male, 69.2% with paroxysmal AF) who were arrhythmia-free at 12 months (excluding 3-month "blanking period"), Catheter-ablation (CA) is superior to antiarrhythmic drugs (AADs) in patients with symptomatic atrial fibrillation (AF), but AF may re-occur despite multiple re-do procedures and recent technical improvements 1,2 . Most arrhythmia recurrences are identified within the first year after the procedure, while further long-term follow-up strategy for initially "successfully" treated patients is less well defined and inconsistently reported 1-9 .Several studies described a progressive increase in the arrhythmia recurrence rates over time in patients with initial post-ablation suppression of AF 4-6 . It is reported that 10-40% of patients who were arrhythmia free within the first post-procedural year experienced very late recurrence of AF (VLRAF) over long-term follow-up 2-9 . Several scoring systems (i.e., the APPLE, ALARMc and BASE-AF2 score) were recently proposed to predict the short-term risk of AF recurrence after the procedure 10-12 . However, none of these scores have addressed VLRAF occurring in patients who were free of AF at 1 year post procedure. Importantly, reliable identification of increased risk of VLRAF could strongly influence decision-making regarding the long-term use of oral anticoagulation and/or AAD therapy as well as the long-term monitoring strategy after the procedure 1,2 . Due to altered risk/benefit ratio, multiple AF ablation procedures may not be justified in patients at high risk of recurrent AF, and reliable prediction of VLRAF could optimize the patient selection for re-do CA 1,2,9,11 .

Catheter ablation (CA) of atrial fibrillation (AF) is currently one of the most commonly performed electrophysiology procedures. Ablation of paroxysmal AF is based on the elimination of triggers by pulmonary vein isolation (PVI), while different strategies for additional AF substrate modification on top of PVI have been proposed for ablation of persistent AF. Nowadays, various technologies for AF ablation are available. The radiofrequency point-by-point ablation navigated by electro-anatomical mapping system and cryo-balloon technology are comparable in terms of the efficacy and safety of the PVI procedure. Long-term success of AF ablation including multiple procedures varies from 50 to 80%. Arrhythmia recurrences commonly occur, mostly due to PV reconnection. The recurrences are particularly common in patients with non-paroxysmal AF, dilated left atrium and the "early recurrence" of AF within the first 2–3 post-procedural months. In addition, this complex procedure can be accompanied by serious complications, such as cardiac tamponade, stroke, atrio-esophageal fistula and PV stenosis. Therefore, CA represents a second-line treatment option after a trial of antiarrhythmic drug(s). Good candidates for the procedure are relatively younger patients with symptomatic and frequent episodes of AF, with no significant structural heart disease and no significant left atrial enlargement. Randomized trials demonstrated the superiority of ablation compared to antiarrhythmic drugs in terms of improving the quality of life and symptoms in AF patients. However, nonrandomized studies reported additional clinical benefits from ablation over drug therapy in selected AF patients, such as the reduction of the mortality and stroke rates and the recovery of tachyarrhythmia-induced cardiomyopathy. Future research should enable the creation of more durable ablative lesions and the selection of the optimal lesion set in each patient according to the degree of atrial remodeling. This could provide better long-term CA success and expand indications for the procedure, especially among the patients with non-paroxysmal AF.

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Atrial fibrillation is the most common sustained arrhythmia in clinical practice, associated with increased mortality, risk of stroke and heart failure, as well as the reduction of the quality of life. Atrial fibrillation may be encountered in young otherwise healthy individuals, due to the isolated electrophysiological disorder limited mostly to the pulmonary veins and posterior left atrial wall, or associated with the presence of advanced underlying heart disease and numerous cardiac and non-cardiac comorbidities with significant structural remodeling of the atrial myocardium. Due to limited efficacy and serious side effects of antiarrhythmic drugs, catheter ablation of atrial fibrillation, based on the pulmonary vein isolation for paroxysmal atrial fibrillation and adjunctive substrate modification for persistent atrial fibrillation, has emerged as an attractive and promissing alternative therapeutic option for selected patients with atrial fibrillation. In this review article, we discuss the electrophysiological left atrial abnormalities underlying lone atrial fibrillation and the role of pulmonary veins in pathophysiology of arrhythmia, and we summarize results of the studies on the long term outcome of catheter ablation of atrial fibrillation, as well as the studies on comparison of antiarrhythmic drugs with catheter ablation for treatment of atrial fibrillation. In addition, we present available data that provide better understanding of mechanisms, diagnosis, prevention and treatment of specific procedure-related complications and discuss current periprocedural anticoagulation strategies and their impact on the thromboembolic risk reduction.

IntroductionThe aim of this study was to assess the effects of preoperative pulmonary rehabilitation (PPR) on preoperative clinical status changes in patients with chronic obstructive pulmonary disease (COPD) and non-small cell lung cancer (NSCLC), and net effects of PPR and cancer resection on residual pulmonary function and functional capacity.Material and methodsThis prospective single group study included 83 COPD patients (62 ±8 years, 85% males, FEV1 = 1844 ±618 ml, Tiffeneau index = 54 ±9%) with NSCLC, on 2–4-week PPR, before resection. Pulmonary function, and functional and symptom status were evaluated by spirometry, 6-minute walking distance (6MWD) and Borg scale, on admission, after PPR and after surgery.ResultsFollowing PPR significant improvement was registered in the majority of spirometry parameters (FEV1 by 374 ml, p < 0.001; VLC by 407 ml, p < 0.001; FEF50 by 3%, p = 0.003), 6MWD (for 56 m, p < 0.001) and dyspnoeal symptoms (by 1.0 Borg unit, p < 0.001). A positive correlation was identified between preoperative increments of FEV1 and 6MWD (r s = 0.503, p = 0.001). Negative correlations were found between basal FEV1 and its percentage increment (r s = –0.479, p = 0.001) and between basal 6MWD and its percentage change (r s = –0.603, p < 0.001) during PPR. Compared to basal values, after resection a significant reduction of most spirometry parameters and 6MWD were recorded, while Tiffeneau index, FEF25 and dyspnoea severity remained stable (p = NS).ConclusionsPreoperative pulmonary rehabilitation significantly enhances clinical status of COPD patients before NSCLC resection. Preoperative increase of exercise tolerance was the result of pulmonary function improvement during PPR. The beneficial effects of PPR were most emphasized in patients with initially the worst pulmonary function and the weakest functional capacity.