Characteristics and outcomes of catheter ablation of ventricular arrhythmias originating from the left ventricular summit

FUNDING ACKNOWLEDGEMENTS: Type of funding sources: None. INTRODUCTION: Catheter ablation (CA) of the left ventricular summit (LVS) arrhythmias is a challenging procedure due to the inherent complexity anatomy of that region. Different anatomical approaches are usually performed for mapping this area including deep intramural location. The objective of this study is to investigate the procedural outcomes of ablation of LVS arrhythmias. METHODS: Retrospective analysis of 32 consecutive patients (mean age 58±12 years old) who underwent CA of LVS arrhythmia in a single center. Baseline characteristics, procedural parameters and clinical outcomes were analyzed. RESULTS: All LVS arrhythmias had inferior and vertical axis (positive inferior leads with negative aVR and aVL leads). LBBB pattern was found in 25/32 (78%) and RBBB pattern in 7/32 (22%). 14/32 (44%) patients presented a "w" morphology in DI lead. 18/32 (56%) cases showed abrupt V3 transition. 13/32 (41%) patients had a previous failed ablation. Direct mapping of the intramural septum, through the septal perforator veins, was performed using a wire or a multipolar 2Fr catheter in 19 patients (59%). The earliest activation area was recorded in LCC-RCC in 13 patients (41%) followed by a septal perforator vein in 9 patients (28%). Most patients required multisite sequential ablation for achieving success (20 patients, 62%). Acute arrhythmia suppression was achieved in 22 patients (69%) and only 1 patient presented a complication (pericardial tamponade). Late success was noted in 3 patients (9%). During a median follow up of 9,79±8,6 months, 23 patients (72%) maintained a sustained acute success (80% reduction of PVC burden at least) None of the 9 patients without sustained acute success needed to repeat ablation. CONCLUSIONS: Ablation of LVS arrhythmias is a challenging procedure with frequent previous ablation attempts. The earliest activation area is commonly found between LCC-RCC junction and in the intramural septum. Multisite non-conventional anatomical mapping and ablation steps are required to obtain a sustained success. [Figure: see text] [Figure: see text]