Abstract Body (Do not enter title and authors here): Background
The novel concept of metabolic dysfunction-associated steatotic liver disease (MASLD) emerged to facilitate diagnosis and emphasize the underlying pathophysiology. However, research validating its prognostic significance, especially for nonatherosclerotic outcomes, is lacking.

Hypothesis
MASLD is associated with an increased risk of cardiovascular disease.

Aim
To determine the prognostic impact of MASLD on cardiac failure, arrhythmias, arrest, key atherosclerotic cardiovascular outcomes, and all-cause mortality.

Methods
In this nationwide retrospective cohort study involving 61 centers, a total of 17,073,511 adults evaluated from 2014 to 2024 were categorized into MASLD and two control groups differing on metabolic dysfunction status. We adjusted for traditional cardiovascular risk factors using propensity score matching with a greedy nearest-neighbor algorithm and 0.1-caliper for pooled standardized mean differences. Cox regressions were used to compare all-cause mortality and cardiovascular outcomes between MASLD and reference groups.

Results
After a 10-year follow-up, patients with MASLD exhibited greater risks for atrial fibrillation (HR, 1.53; 95% CI, 1.51–1.56), atrial flutter (HR, 1.85; 95% CI, 1.78–1.91), ventricular tachycardia (HR, 2.04; 95% CI, 1.97–2.11), ventricular fibrillation/flutter (HR, 2.18; 95% CI, 2.00–2.37), cardiac arrest (HR, 2.64; 95% CI, 2.53–2.78), heart failure with preserved ejection fraction (HR, 2.69; 95% CI, 2.63–2.74), heart failure with reduced ejection fraction (HFrEF), ischemic heart diseases, stroke, and all-cause mortality compared with patients without metabolic dysfunction. Comparisons between MASLD and metabolic dysfunction yielded significant associations for increased risk with MASLD, except for HFrEF.

Conclusion
MASLD is a strong independent risk factor for mortality, nonatherosclerotic, and atherosclerotic cardiovascular outcomes.