LEFT FREE WALL-SIDED MAHAIM TYPE FIBER AND AV NODAL REENTRY TACHYCARDIA -- UNUSUAL BUT NOT IMPOSSIBLE COMBINATION

A 52-year-old patient with previous catheter ablation of AV nodal reentrant tachycardia (AVNRT) had a redo procedure for reported recurrence. During the study AVNRT was not inducible, but a previously unrecognized left-sided Mahaim type accessory pathway was diagnosed and ablated successfully.

Review of interventional electrophysiology in Bulgaria in 2019 and 2020: data from the electronic ablation registry BG-EPHY

This study presents data from the national electronic registry BG-EPHY on electrophysiologic (EP) cardiac ablations in 2019 and 2020. Material and methods. This is a retrospective study of a full two-year sample of the BG-EPHY registry. Sex and age distribution of the patients, number of ablations, electroanatomic mapping (EAM), irrigated ablations, distribution of different types of arrhythmia, intraprocedural success and complications are presented. Results. In 2019 four EP laboratories performed 1033 ablations in 652 men (63.1%) and 381 women, incl. 12 pediatric ablations (1.2%). EAM was used in 46.7% of the procedures, irrigation catheter was used in 52.2%, and cryocatheter – in 0.5%. The most common procedure was pulmonary vein isolation, followed by ablation for AV nodal reentrant tachycardia and typical atrial fl utter. In 2020 fi ve EP laboratories performed 835 ablations in 508 men (60.8%) and 327 women, incl. 8 pediatric ablations (1%). EAM was used in 50.9% of the ablations, irrigation catheter – in 54.5%, and cryocatheter – in 3.8%. The most common procedure was again pulmonary vein isolation. Ablation of typical atrial fl utter was the second most frequently performed procedure, ahead of AV nodal reentrant tachycardia. In 2020 the number of ablations of accessory pathways also distinctly dropped by 37%. In both years the acute success was over 98%, and the complications were less than 2%. Conclusion. The national registry of electrophysiology collects systematically and continuously basic data on all cardiac ablations performed in the country. The structure of the EP service is remarkably similar to other European countries. Acute success is very high, while intraprocedural complications are rare. In 2020 the number of the ablations dropped by 19% as a consequence of the COVID-19 pandemic.

Comparison of conventionally performed and electroanatomic mapping system guided catheter ablation for AV nodal reentrant tachycardia - prospective single-centre study

Funding Acknowledgements Type of funding sources: None. Introduction Radiofrequency (RF) catheter ablation in atrioventricular nodal reentry tachycardia (AVNRT) is highly effective. Three-dimensional electroanatomic mapping system (EAMS)-guided procedures are becoming more widespread. Purpose We aimed to compare EAMS-guided procedures to conventionally, only-fluoroscopy approach for slow pathway ablation. Methods 152 patients undergoing electrophysiological study and slow pathway ablation due to documented AV nodal reentrant tachycardia were included in our prospective single-centre study. In 102 patients the procedure was performed conventionally (Group 1) and 50 patients underwent an electroanatomic mapping system (EAMS) -guided approach (Group 2). Results In Group 2, 80% of the procedures were performed without the use of radiation. The procedure time (median (interquartile range): 65 (50-84) min vs. 75 (60-96.3) min, p =0.005) was significantly shorter in Group 1, with longer fluoroscopy time (4.2 (2.4-7.9) min vs. 0 (0-0) min, p < 0.001). There was no difference either in the number of RF applications (mean ± standard deviation 10.8 ± 8.5 vs. 10.2 ± 7.7, p = 0.66) or in the ablation time (297 ± 237 s vs. 294 ± 196 s, p = 0.74). All patients were treated successfully. One recurrence occurred in each groups during the follow-up. Conclusions In our series, EAMS-guided approach for slow pathway ablation was associated with reduced fluoroscopy and longer procedure time compared to conventional, only-fluoroscopy approach. No difference was found in ablation time, success rate or recurrence.

P1010Electrophysiological characteristics of paroxysmal tachycardia in children with short PQ interval

Introduction It is well known that children with short PQ interval can have different types paroxysmal tachycardia (PT). Combination of short PQ interval with PT is called Lown-Ganong-Levine (LGL) syndrome. We have hypothesized that in children with short PQ interval electrophysiological types of PT do not correlate with shortening of PQ interval. Purpose The aim of the study was to assess the PT types based on results of the electrophysiological studies and radiofrequencycatheter ablation (RFA), and to estimate the AV conduction parameters and their dynamic changes before and after the procedure. Materials and methods of research: 55 children with supraventricular tachycardia (SVT) and short PQ interval were examined. The examination included:ECG, 24-hour Holter monitor, transesophageal pacing study (TEPS), intracardiac electrophysiological study (EPS). 22 children underwent RFA procedure. During the period of the study 55 children had 111 TEPS and 28 EPS studies. Results 21 (38,2%) children had orthodromic AV reentrant tachycardia with accessory pathway (AVRT), 27 (49,1%) had typical (slow-fast) AV nodal reentrant tachycardia (AVNRT), 2 (3,6%) had atypical AVNRT, 1 (1,8%) had combination of typical and atypical AVNRT, 1 (1,8%) had atrial ectopic tachycardia combined with atypical AVNRT, 4 (7,3%) had spontaneous atrial fibrillation or atrial flutter, 3 (5,4%) had combination with typical AVNRT and 1 child (1,8%) had AVRT. PQ interval measured 107,2 ms (83–120ms). 22 (40%) children underwent RFA-13 children with typical AVNRT, 9 with AVRT. In children with AVNRT tachycardia cycle length was 229–425 ms (309,8±67,6ms). Primary RFA was effective in 10 (76,9%) children. The AVNRT recurrence was found in 3 (13,6%) cases after 7,2±4,3 month from the time of procedure. After slow pathway ablation PQ interval length didn't change (107,1±9,1ms compared to 108,2±7,1ms; p=0,2). No change occurred with the maximal rate of 1:1 conduction through AV node (187,8±14,8 imp/min compared to187±12,5 imp/min; p=0,2). Effective refractory period of AV node (AVNERP) increased by a small amount (288,9±14ms, compared to 266±42,7ms; p=0,06). 9 (40,9%) children underwent RFA of the accessory pathway (AP). In all of the cases there were concealed AP with the left-sided localization. AVRT cycle length was 259–382 ms (304,2±41,2ms). After RFA of concealed AP maximal rate of 1:1 conduction through AV node increased by a small amount (220±26,4 imp/min compared to 191,2±23,6 imp/min) and AVNERP decreased (256,7±25,2ms compared to 268,6±38,9ms; p=0,09).After RFA of AP PQ interval length didn't change (110±5,9ms compared to 110±5ms; p=0,1). Conclusion In children with short PQ interval PT was associated with dual physiology of AV connection or with concealed AP. After the successful RFA in children with AVNRT and AVRT there was no PQ interval normalization, which remained short in all examinations. Thus, short PQ- interval is a co-existing phenomenon in children with AVNRT and AVRT.