Abstract Body (Do not enter title and authors here): Background
Emerging evidence suggests a potential link between atrial fibrillation and dementia, yet mortality data for patients with both conditions remain sparse. This study aims to investigate the trends in mortality associated with atrial fibrillation/flutter and dementia in the United States over a two-decade period.

Methods
Utilizing the Centers for Disease Control and Prevention's Wide-ranging Online Data for Epidemiologic Research database, we identified individuals aged 55 and above who had both atrial fibrillation/flutter and dementia listed as either an underlying or contributing cause of death. We calculated age-adjusted mortality rates (AAMR) per 100,000 individuals and annual percent change (APC). Analysis is stratified by gender, race/ethnicity, and geographic region.

Results
Between 1999 and 2020, there were 417,172 deaths associated with both atrial fibrillation/flutter and dementia. The overall AAMR surged from 10.12 in 1999 to 44.16 in 2020 (APC: 6.7 [95% CI, 6.15-7.44], p-trend<.001), a rise observed consistently across gender, race, and region. Men exhibited a higher AAMR than women (26.6 vs 25.9). Among racial groups, non-Hispanic White individuals had a higher AAMR compared to non-Hispanic Black individuals (28.71 vs 16.02). Geographically, the Western U.S. recorded the highest AAMR (28.88 [95% CI, 28.69-29.06]), while the Midwest experienced the most significant APC increase (3.89 [95% CI, 2.56-6.12]).

Conclusion
There has been a significant and steady rise in mortality rates associated with atrial fibrillation/flutter and dementia, affecting all genders and racial groups. This alarming trend highlights the urgent need for specialized interventions to mitigate this escalating public health issue.