Abstract Body (Do not enter title and authors here): Background
Direct current cardioversion (DCCV) carries a risk of stroke in atrial fibrillation (AF) patients. Hence, published guidelines for mitigating this risk with oral anticoagulation (OAC). There is no consensus agreement on the safest approach when cardioverting patients with left atrial appendage occlusion device in situ.

Aims
We aimed to compare association of pre-DCCV imaging with safety and outcomes in patients with WATCHMAN™ undergoing elective DCCV for atrial arrhythmias (AA)

Methods
This was a retrospective cohort study of patients who received DCCV for AA during follow up after LAAO procedure from 2016-2024 within a large health care system. Safety endpoint was freedom from stroke, all-cause mortality, device embolism, and systemic embolism within 30-days post DCCV. Significant peri-device leak (PDL) was defined as > 5mm on cardiac imaging.

Results
A total of 119 patients were included, more females 70 (59%), with more than half (64 (54%)) receiving a first-generation WATCHMAN™ 2.5, while the rest had WATCHMAN FLX™. Median age at presentation was 77 years (72,82), BMI of 31 kg/m2 (26,37), average CHADSVASC score of 4.5 and HASBLED score of 3. There was a median duration of 10 months (3,21) between LAAO to presentation for DCCV .
Forty-four (37%) patients had pre-DCCV imaging, while 75 patients did not receive pre-procedural imaging. Between the two groups, there was no significant difference in OAC (VKA-antagonist/DOAC) usage prior to presentation (8 (18.6%) vs 12 (16.4%), P=0.9), with single antiplatelet therapy was the prevalent anti-thrombotic regimen. There was no significant difference in CHADSVASC, HASBLED, age, LVEF, or timing of presentation relative to the LAAO procedure. Higher percentage of patients were discharged on OAC post DCCV in the imaging cohort (13 (30.2%) vs 14 (19.4%), p=0.27), the difference was not significant. No Device related thrombus (DRT) nor significant PDL was detected on imaging. But non-significant PDL ranging from 2mm-4.7mm was found in 8 (18.1%) out of 44 patients who had imaging prior to DDCV. Safety endpoint was achieved in both cohorts with zero adverse events occurring during the 30 day follow up period post-DCCV.

Conclusion
Elective cardioversion for atrial arrhythmias is safe in patients with WATCHMAN™. There were no post-DCCV stroke events in the overall cohort and no DRT identified in the pre-DCCV imaging subgroup. Further studies are needed to determine when pre-DCCV imaging is warranted in this population.