To evaluate the effect of electro-anatomical mapping on success rate and fluoroscopy time in ablation of supraventricular tachycardia substrates in a large group of children.

Patients referred from multiple centres in the Netherlands and who received a first ablation for supraventricular tachycardia substrates in the Leiden University Medical Center between 2014 and 2020 were included in this retrospective cohort study. They were divided in procedures in patients with fluoroscopy and procedures in patients using electro-anatomical mapping.

Outcomes of ablation of 373 electro-anatomical substrates were analysed. Acute success rate in the fluoro-group (n = 170) was 95.9% compared to 94.5% in the electro-anatomical mapping group (n = 181) (p = 0.539); recurrence rate was 6.1% in the fluoro-group and 6.4% in the electro-anatomical mapping group (p = 0.911) after a 12-months follow-up. Redo-ablations were performed in 12 cases in the fluoro-group and 10 cases in the electro-anatomical mapping group, with a success rate of 83.3% versus 80.0%, resulting in an overall success rate of 95.9% in the fluoro-group and 92.8% in the electro-anatomical mapping group (p = 0.216) after 12 months. Fluoroscopy time and dose area product decreased significantly from 16.00 ± 17.75 minutes (median ± interquartile range) to 2.00 ± 3.00 minutes (p = 0.000) and 210.5 µGym2 ± 249.3 to 32.9 µGym2 ± 78.6 (p = 0.000), respectively. In the fluoro-group, four complications occurred (2.0%) and in the electro-anatomical mapping group no complications occurred.

These results demonstrate that ablations of supraventricular tachycardia substrates in children remain a highly effective and safe treatment after the introduction of electro-anatomical mapping as a standard of care, while significantly reducing fluoroscopy time and dose area product.

To evaluate the results of balloon dilatation of stenotic homografts in children, adolescents, and young adults and to identify factors that might influence or predict the effect of the dilatation.

Homografts are widely used in congenital cardiac surgery; however, the longevity remains a problem mostly because of stenosis in the homograft. The effect of treatment by balloon dilatation is unclear.

In a retrospective study, the effect of balloon dilatation was determined by the percentage of reduction of the peak systolic pressure gradient over the homograft during catheterisation and the postponement of re-intervention or replacement of the homograft in months. Successful dilatations – defined in this study as a reduction of more than 33% and postponement of more than 18 months – were compared with unsuccessful dilatations in search of factors influencing or predicting the results.

The mean reduction of the peak systolic pressure gradient was 30% in 40 procedures. Re-intervention or replacement of the homograft was postponed by a mean of 19 months. In all, 14 balloon dilatations (35%) were successful; the mean reduction was 49% and the mean postponement was 34 months. The time since homograft implantation, the presence of calcification, the homograft/balloon ratio, and the pressure applied during dilatation all tended to correlate with outcome, but were not statistically significant.

Balloon dilatation is able to reduce the peak systolic pressure gradient over homografts in a subgroup of patients and can be of clinical significance to postpone re-intervention or pulmonary valve replacement.