Fehmi Keçe

Predicting Early Reconnection with Procedural and Biophysical Parameters 147 7 °C or a reduced diaphragmatic movement was observed. Procedural characteristics including number of applications and unsuccessful freezes per vein (defined as aborted applications because of absence of PV isolation within 90 s) and time-to-isolation as well as biophysical data were evaluated as potential predictors for ERC (7). 7.2.3 Follow-up Patients were followed 3, 6 and 12 months after ablation with a 24-Holter and an exercise test. In addition, all symptomatic patients were encouraged to immediately visit the outpatient clinic for rhythm documentation on 12-lead ECGs or additional 24-Holter registration during palpitations. After the procedure, anti-arrhythmic drugs were restarted and stopped at the first follow-up visit if no AF/Atrial tachycardia recurrence was documented. After a blanking period of 3 months, ablation success was defined as the absence of any documentation of AF/atrial tachycardia lasting longer than >30 seconds on ECG, Holter or device recording. 7.2.4 Statistical analysis Categorical variables were compared using the Chi-square test (or Fisher exact test when appropriate) and continuous variables with the independent T-test (or Mann-Whitney U test). Predictors of ERC were identified by multivariable logistic regression using variables with statistically significant differences in the univariable analysis between the groups. This resulted in a model providing odds ratios and 95% confidence intervals for the primary outcome. A receiver operating characteristics (ROC) curve corresponding to the selected logistic regression was constructed and the area under the curve was calculated to provide a summary measure of the accuracy of the prediction model. Based on the individual coefficients of the regression model a formula was created and based on the ROC curve, a combined cut-off-value was determined for the significant parameters. Finally, the AF-free survival was compared between groups using the log-rank test. A p-value of <0.05 was considered statistically significant. R-studio (Version 1.0.143 – © 2009-2016 RStudio, Inc.) was used for data extraction and calculation of biophysical data from the console files and SPSS (version 23, SPSS Inc., Chicago, IL, USA) was used for data analysis.