Predictors of transition to transseptal path in patients with wolff-parkinson-white syndrome with left-sided accessory pathway undergoing first choice retrograde aortic abblated tract

Introduction: Wolff-Parkinson-White syndrome is the most common type of preexcitation. It is known that radiofrequency catheter ablation is safe and has high success rates in the curative treatment of WPW syndrome. Venous and arterial access routes are used for ablation according to the localization of the accessory pathway. While the venous route is used in right-sided accessory pathways, the transaortic (arterial) or transseptal (venous) approach is preferred in patients with left-sided accessory pathways. Up to now, no clear recommendations have been made regarding the optimal approach for left-sided accessory pathway ablation. In our clinic, the first approach to left-sided accessory pathways is usually the retrograde aortic route. The aim of this study is to determine the predictive factors that should be preferred first in the patient group with left-sided accessory pathways. Materials and Methods: Our study included 557 patients with Wolf- Parkinson-White syndrome who underwent ablation in the Cardiology Department of Ankara City Hospital and Yüksek İhtisas Hospital between January 2017 and March 2024. Of these patients, 235 were excluded because they had a right-sided accessory pathway. 322 patients had a left-sided accessory pathway and the study continued with this patient group. All patients were over 18 years of age. Electrocardiography parameters, echocardiography findings, electrophysiological study (EPS) reports, weight and height parameters were obtained from the hospital data system. Results: 322 patients with Wolf-Parkinson-White syndrome and left-sided accessory pathway were included in the study. The mean age of the patients was 38.96±13.40 years, the minimum patient age was 18, and the maximum patient age was 78. 32.3% of the patients were female and 67.7% were male. 242 of the patients had manifest and 80 had concealed accessory pathways. Of the 55 patients who underwent ablation via the transseptal route, 2 had hypertrophic cardiomyopathy (HCM) and 6 had hypertension (HT). The mean diameter of the ascending aorta (AA) was 32.29±2.85 mm, and the left atrium (LA) was 34.33±3.03 mm. The BMI values of the patients were 24.94±3.94 in the group that was successful with the retrograde aortic route and 24.24±4.68 in the group that was unsuccessful, and no statistical difference was observed between thetwo groups. The EF values of the patients were 61.66±3.91% in the group that was successful with the retrograde route and 61.07±3.82% in the group that was unsuccessful, and no statistical difference was found between the two groups in terms of EF values. In the study population, other echocardiographic IVS, LVAD, left ventricular EDD values were similar in both groups between the patient group with successful retrograde aortic ablation and the group with unsuccessful ablation. Again, left atrium values were 34.39±2.97 mm in the group with successful retrograde aortic ablation and 34.04±3.45 mm in the unsuccessful group, and left atrium values were similar between the two groups. In 82.9% of the patients, ablation with retrograde aortic route was successful. When patients who were successful with retrograde aortic route ablation and those who were unsuccessful (transseptal route was used) were compared, it was determined that the AA values of the patients were significant as a predictive factor for transseptal transition. It was observed that ablation with retrograde aortic route was unsuccessful in the patient group with an ascending aorta diameter of 31 mm and smaller (p<0.01). Although there was no statistical difference between the accessory pathway localizations of patients who were successful and those who were unsuccessful as a result of radiofrequency ablation procedure (p>0.05), it was observed that accessory pathway localization was on the lateral wall in 23 (41.8 %) of 55 patients who underwent transseptal transition. Conclusion: In our study, it was observed that the rate of switching to transseptal intervention was higher in patients with small aortic diameter who underwent ablation with the retrograde aortic route as the first choice. It was also observed that the rate of transseptal transition was high in accessory pathways located on the lateral wall. As a result, it may be logical to start ablation with the transseptal approach as the first choice in patients with small aortas and lateral/anterolateral accessory pathways.