Abstract Body (Do not enter title and authors here):
BACKGROUND: Ventricular fibrillation (V-fib) is a leading cause of sudden cardiac death, particularly in patients with comorbid chronic ischemic heart disease (CIHD) and chronic kidney disease(CKD). While trends in each condition have been studied, a potential intersection among all three has not been explored.

Research Question: The objective of this study was to examine national trends in V-fib-related mortality among adults ≥25 years with comorbid CIHD and CKD in the U.S from 1999 to 2023 and how these patterns vary by year, gender, race, and region in the U.S.

METHODS: This is a retrospective analysis of mortality data among U.S. adults aged ≥25 years from 1999 to 2023, using the CDC WONDER database(Centers for Disease Control and Prevention Wide-Ranging Online Data for Epidemiologic Research). International Classification of Diseases, Tenth Revision (ICD-10 codes) were used to identify deaths attributed to V-fib (I49), CIHD (I25), and CKD (N18). Age-adjusted mortality rates (AAMRs) per 100,000 population were calculated, and annual percentage changes (APCs) were analyzed using Joinpoint regression. Outcomes were stratified by year, sex, race and census region.

RESULTS: Between 1999 and 2023, there were 136,584 V-fib-related deaths among adults aged ≥ 25 with comorbid CIHD and CKD. The AAMR value declined from 5.63 in 1999 to 3.84 in 2002 (APC: -11.90%, 95% CI: -13.38 to -10.38), then to 2.44 in 2007 (APC: -9.07%, 95% CI: -10.24 to -7.89). A slower decline continued to 1.73 in 2018 (APC: -3.10%, 95% CI: -3.45 to -2.75), followed by a brief rise to 1.83 in 2021 (APC: +2.01%, 95% CI: -3.34 to +7.65), and then again, a drop to 1.61 in 2023 (APC: -5.51%, 95% CI: -9.89 to -0.92). AAMR was higher in males than females throughout (1999:8.8 vs 3.38, 2023: 2.63 vs 0.75). In 2023, AAMR by race was highest in Black/African Americans: 1.93, Whites: 1.61, Asian/Pacific Islanders: 1.26, and American Indian/Alaska Natives: 1.13. Regionally, the highest AAMR was in the South (1.82), followed by the Midwest (1.54), with the West and Northeast having similar values (1.43).

CONCLUSION: Despite significant early declines, V-fib-related mortality in adults with CIHD and CKD has plateaued in recent years. Men and Black/African American individuals remained disproportionately affected. Although regional differences were modest, rates were highest in the South. These trends highlight the need for targeted prevention in this high-risk group.