2.4 Procedural endpoints
The procedural endpoint for AVNRT was noninduction, with and without the isoprenaline challenge. Presence of slow pathway conduction with up to one ”echo” beat was allowed. The procedural endpoint for AVRT ablation was the elimination of AV and VA conduction across the AP. Additionally, noninduction of tachycardia was always tested with or without an isoprenaline challenge. For AT, the procedural endpoint was termination with ablation and noninduction of tachycardia with or without an isoprenaline challenge.
2.5 Procedural complications
Major complications were defined as events which were directly related to the CA procedure and required an intervention, prolonged hospital stay, and/or had a negative influence on the patient’s long-term health. Minor complications were defined as a transient high-degree atrioventricular block that resolved during the procedure, pericardial effusion without a hemodynamic compromise requiring no intervention, and other adverse events that would not be qualified as major complications but were still directly related to the CA procedure.
2.6 Follow-up
All patients received post-procedural instructions for further actions in case of recurrence. During subsequent outpatient appointments, patients underwent clinical examinations and had a 12-lead ECG recorded. If the patient had signs and symptoms of recurrence of tachycardia, further diagnostic tests were performed, including 24-hour holter monitoring, monitoring with wearable event recorders, and/or repeated EP study. Recurrences were confirmed and noted during the EP study. If the patient declined repeated EP study, the tachycardia recorded on 12-lead ECG or 24-hour holter was noted as a recurrence.
2.7 Statistical analysis
Descriptive data of continuous variables are presented as mean ± standard deviation or as median and interquartile range (25% - 75%). Categorical variables are presented as numbers with percentages. Differences between groups were evaluated by an independent Student’s t-test for normally distributed continuous variables and the Mann-Whithey U test for non-normally distributed continuous variables, while χ2 was used for categorical variables. Categorical variables with fewer than two values were compared with Fisher’s exact test. A one-way ANOVA test was used for the analysis of the learning curve. Time to first recurrence of tachycardia was plotted using the Kaplan-Meier product and compared by the log-rank test. All statistical analyses were performed using SPSS (IBM, Armonk, NY, USA) statistical software version 25. A p value of <0.05 was considered statistically significant.
3.0 Results