Abstract Body (Do not enter title and authors here): Background
Sudden cardiac death from ventricular tachycardia (VT) and ventricular fibrillation (VF) remains a major cause of mortality in heart failure patients. Understanding long-term trends and disparities by sex, ethnicity, geography, and urbanization is essential for equitable prevention strategies.

Methods
We used CDC WONDER Multiple Cause of Death data (1999–2023) to identify deaths listing both heart failure and VT or VF. Age-adjusted mortality rates (AAMR) per 1,000,000 were calculated by sex, ethnicity, U.S. census region, and 2013 urbanization level. Joinpoint regression was used to assess temporal trends and average annual percent change (AAPC), with p<0.05 considered significant.

Results
Males consistently exhibited higher mortality than females (2023 AAMR: 3.6 vs.1.2). Females showed a significant decline (AAPC -12.32, p=0.028), while males had a non-significant increase (AAPC 1.12, p=0.32). Black individuals had the highest mortality (2023 AAMR: 4.1), followed by Whites (2.7) and Hispanics (2.0). Despite a decreasing trend in Black patients (AAPC -4.49, p=0.23), disparities persisted. Asians had the lowest mortality but an upward trend (AAPC 0.69, p=0.72).

By urbanization, nonmetro (Noncore) areas had higher mortality than large metros (2023 AAMR: 3.4 vs. 2.1). Trends were stable across groups: Noncore (AAPC 0.27, p=0.93), Large Central Metro (AAPC 1.29, p=0.80), Medium Metro (AAPC -0.58, p=0.71). Regionally, the South had the highest mortality (2023 AAMR: 3.8) and the Northeast the lowest (2.0). The West showed the largest rise (AAPC 1.88, p=0.48), while the South remained flat (AAPC -0.06, p=0.77).

Conclusion
VT and VF-related mortality in heart failure remains disproportionately high in males, Black individuals, rural communities, and the Southern U.S. While some groups—particularly females—show improvement, most others have seen stable or rising trends. These findings highlight persistent disparities and the need for targeted interventions to reduce arrhythmic death in vulnerable populations.