Safety aspects of very high power very short duration atrial fibrillation ablation using a modified radiofrequency RF-generator: Single-center experience.

INTRODUCTION

High power short duration (HPSD) ablation proved to be an effective and safe ablation technique for atrial fibrillation (AF). In former case series, a significant amount of postablation coagulation at the catheter tip as well as silent cerebral lesions (SCL) in postprocedural cerebral magnetic resonance (cMRI) have been identified in patients undergoing de-novo AF ablations with very high power 90 W short duration (vHPvSD) ablations using the QDot ablation catheter in combination with a novel RF generator (nGEN, Biosense Webster). Therefore, the RF generator software has been recently modified.

METHODS AND RESULTS

Consecutive patients undergoing a first AF ablation including pulmonary vein isolation (PVI) with vHPvSD (90 W, with a predefined ablation time of 3 s at posterior left atrium (LA) wall sites and 4 s at other ablation sites) using the QDOT Micro ablation catheter (Biosense Webster) in conjunction with the technically modified nGEN RF generator (software V1c; Biosense Webster) were included. Procedural characteristics including first-pass isolation per pulmonary vein (PV) pair and early reconnection location within the 30-min waiting period were recorded. In all patients postablation endoscopy to document any thermal esophageal injury (EDEL) and in eligible patients a cMRI to detect silent cerebral events (SCEs)/lesions were performed. All acute procedure-related complications were recorded during the time until hospital discharge. Furthermore, short-term and midterm success after 3 and 6-12 months of follow-up was investigated. In total, 34 consecutive patients (67 ± 9 years; 62% male; 68% paroxysmal AF) were included. First-pass isolation of all PVs was achieved in 6/34 (18%) patients. First-pass isolation was seen in 37/68 (54%) of PV pairs. Early reconnection occurred in 11 (32%) patients (including reconnections at posterior LA wall sites n = 6 and at nonposterior sites n = 5). No patient had an EDEL (0%). In 6/23 (26%) patients undergoing postablation cerebral MRI SCEs were identified. In six patients, coagulation on the catheter tip was detected at the end of the procedure. No further peri- or postprocedural complications were detected. Early AF recurrence before discharge was seen in 1/34 (3%) of the patients included in this study. Within 3 months 10/34 (29%) revealed AF recurrence during blanking period. After a mean follow-up of 7 months, 31/34 (88%) patients revealed sinus rhythm.

CONCLUSION

AF ablation using 90 W vHPvSD with a specialized ablation catheter in conjunction with a recently modified RF generator was associated with no EDEL in the whole study cohort and 26% SCEs in a subgroup of patients undergoing acute postablation cerebral MRI. Accordingly, to our previously published results, a relevant number of catheter tip coagulations was identified in this patient cohort even after modifications of the RF generator. The vHPvSD ablation technique using the present and the previous generator seems to be associated with a very low rate of esophageal injury. However, the recently revised generator software also produced a relevant number of catheter tip coagulum formation and SCEs.