Similarly high success and low complication rates of catheter ablation for idiopathic premature ventricular contractions from the left and right ventricular outflow tract

Funding Acknowledgements Type of funding sources: None. Introduction Catheter ablation is the first line treatment for idiopathic premature ventricular contractions (PVCs) from the right ventricular outflow tract (RVOT) but not from the left ventricular outflow tract (LVOT), due to presumed lower success and higher complication rates in the LVOT. In this observational single center study we analyzed success rates and complication rates in patients undergoing catheter ablation for idiopathic PVCs with an inferior axis. Methods Patients undergoing catheter ablation for idiopathic PVCs with an inferior axis at Hannover Heart Rhythm Center between 2012 and 2020 were included. Patients were excluded if no activation mapping could be performed because of low PVC activity. Ablation success was defined as complete suppression of the index PVC at the end of the procedure. Results 108 patients (53% male, age 53 ± 17 years) with predominantly symptomatic (94%) PVCs with one (72%), two (20%) or more (8%) morphologies and a PVC count of 22063 ± 14426 /24h were included. 47 PVCs (44%) were located in the RVOT (21 anterior RVOT and 26 septal RVOT) and 39 PVCs (36%) in the LVOT (11 lateral LVOT, 5 septal LVOT, 8 RCC, 2 ACC, 13 LCC). 14 PVCs (13%) had the origin close to the CS/LV summit and 8 PVCs (7%) in the parahisian region. Overall success rate was 82%. Success rates for RVOT and LVOT origin were 98% (46/47 cases) and 97% (38/39 cases) respectively. No significant differences in procedure time (145 ± 68 vs. 158 ± 72 min), ablation time (441 ± 328 vs. 462 ± 307 sec), fluoroscopy time (496 ± 521 vs. 519 ± 473 sec) or minor complications (5 vs. 8) were observed for outflow tract PVCs, and no major complications occurred in this group. However, 3 major complications and significantly lower success rates were observed for non-outflow tract PVCs (0/8 for parahisian origin, 4/14 (29%) for CS/LV summit origin). 2 patients with a parahisian focus experienced higher degree AV block and 1 patient with an LV summit focus had a pericardial tamponade. Conclusion Catheter ablation of PVCs with LVOT origin can be performed with similarly high success and low complication rates compared to PVCs with RVOT origin, and therefore could be considered as first-line therapy like RVOT PVCs. On the other hand, identification of PVCs with a parahisian or CS/LV summit focus should be aspired before an ablation procedure, as these localizations are associated with poorer ablation outcome and higher complication rates.