A proposal for a new scoring system in the prediction of catheter ablation outcomes: Promising results from the Turkish Cryoablation Registry

Although cryoballoon based catheter ablation is an effective therapeutic option in atrial fibrillation (AF), a significant amount of patients failed to remain in sinus rhythm at long term follow-up. Appropriate selection of patients for catheter ablation reduces unnecessary interventions and prevents complications related with catheter ablation. The purpose of our study is to propose a new scoring system in the prediction of recurrence after AF ablation with cryoballoon.A total of 236 patients (54% male, age 54.6 ± 10.45 years and 79.6% paroxysmal) with symptomatic AF underwent an index cryoablation. The first 3 months after AF ablation is defined as blanking period. Predictors of AF recurrence after cryoablation were analyzed with multivariate Cox regression analysis. BASE-AF2 score [acronym stands for Body mass index >28 kg/m(2) (1); Atrial dilatation >40 mm (1); current Smoking (1); Early recurrence (1); duration of AF history >6 years (1) and non-paroxysmal type (1) of AF] is identified by the total number of significant predictors of recurrence in each patient (range=0-6).At median 20 (range: 12-30) months follow-up, 74.5% of the patients were free from AF recurrence. Of these patients, 64 (27.1%) patients had a BASE-AF2 score of ≥3. Patients with AF recurrence had a higher mean BASE-AF2 score (3.27±0.82 vs. 1.1 ± 0.95, p<0.001) compared to patients without AF recurrence. ROC analysis showed that a BASE-AF2 score of ≥3 well predicted AF recurrence with a sensitivity of 80.8% and a specificity of 91.6% (AUC=0.94; 95% CI: 0.89-0.97, p<0.001). A BASE-AF2 score of ≥3 was found to be an independent predictor of AF recurrence (HR: 3.34, 95% CI: 2.34-4.76, p=0.001).BASE-AF2, which was identified as a new scoring system, has well predicted AF recurrence and could be helpful in selecting appropriate patients for interventional strategy.