Introduction As shown in randomized clinical trials first line pulmonary vein isolation (PVI) using cryoballoon technology is superior compared to antiarrhythmic drug therapy regarding the atrial arrhythmia freedom for the treatment of paroxysmal atrial fibrillation (PAF). The optimal timing since first diagnosis for successful ablation is unknown. Furthermore known predictors for success after pulmonary vein isolation were defined in studies with short follow up. The aim of this study was to identify the best time frame for successful PVI and identify markers for success/failure based on follow up data until 8 years. 

Methods In a retrospective analysis 856 patients (male= 493, age= 62, glomerular filtration rate (median= 92,55 ml/min), cardiovascular anamnesis (coronary artery disease (n= 104), structural myocardial damage (n= 33)), cardiovascular risk factors (Diabetes mellitus (n= 123), Hypertension (n= 550)),anemia (defined as hemoglobin concentration in men < 14 g/dl and women < 12 g/dl (n=118)) and time since 1st diagnosis (TFD, median= 27 months) with paroxysmal atrial fibrillation undergoing cryo-balloon based pulmonary vein isolation since 2012 were included. By performing multivariate regression analysis using SPSS-26 we looked for predictors of atrial arrhythmia recurrence. Patients were divided in subgroups regarding the amount of significant parameters and their event free survival. The prediction score was defined as the sum of identified  significant risk factors. 

Results After a median follow-up of 4.5 years (IQR: 2-7 years) the overall freedom from recurrence of atrial arrhythmia after PVI was 66.4%. The multivariate analysis identified anemia as a statistical significant predictor for the recurrence of atrial arrhythmia (p= 0.022). Gender does not have an influence on the outcome of catheter ablation (p= 0.09). We detected TFD (HR= 1,351), hemoglobin concentration (HR= 1,704) und cardiovascular anamnesis (coronary artery disease, structural myocardial damage, HR= 1,877) as significant risk factors for arrhythmia recurrence after pulmonary vein isolation.  As depicted in Figure below Patients with no clinical risk factor have the highest rate of freedom from atrial arrhythmia (78.5 %) after 8 years compared to patients with a higher score. The efficacy of PVI was found to be impaired if performed later than 3 years after 1st diagnosis in the long-term. The score was defined as the sum of identified  significant risk factors. 

Discussion Outcome after pulmonary vein isolation is dependent from several clinical factors. We found that anemia, cardiovascular anamnesis, time from 1st diagnosis and number of cardiovascular risk factors are the strongest predictors for freedom of arrhythmia. The less risk factors are present the better the outcome of ablation therapy will be.

Fig.1: Event free survival of patients after ablation depending on score (purple curve= 0, blue curve= 1, yellow curve= 2, red curve= 3)