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