Long-term outcomes in patients with acute coronary syndrome complicated by new-onset atrial fibrillation: a nationwide cohort study
S Abdi, G Ferrannini, J Tjerkaski, E Svennberg, A J SiddiquiAbstract
Background
Atrial fibrillation (AF) frequently occurs in patients presenting with acute coronary syndrome (ACS) but the prognostic implications of new-onset AF in first-time ACS patients are unclear.
Purpose
To assess the association between new-onset AF after a first ACS and outcomes.
Material and Methods
A nationwide cohort of patients with first time ACS was identified from a registry between 2007 and 2020 and linked to national patient, death, and prescription registers. The study included 139,961 patients with first-time ACS and no prior AF. New-onset AF was defined as AF diagnosed during the index ACS hospitalization or within 30 days. Fine–Gray competing-risk models were used to estimate crude and adjusted sub distribution hazard ratios (HRs) for all-cause mortality, cardiovascular death, stroke, recurrent myocardial infarction (MI), bleeding, and hospital readmission at 30 days, 1 year, and end of follow-up.
Results
Among 139,961 ACS patients without prior AF, 9,291 (7%) developed new-onset AF (mean age 77 years; 64% male), while 130,670 remained AF-free (mean age 68 years; 67% male). Mean follow-up was 6.7 years. New-onset AF was associated with a substantially increased risk of all-cause mortality, with adjusted HRs of 1.73 (1.43–2.08), 1.30 (1.20–1.40) and 1.09 (1.04–1.14) at 30 days, 1 year and end of follow up respectively. The corresponding adjusted HRs for cardiovascular death were 1.50 (0.95–2.37), 1.11 (0.98–1.26) and 0.87 (0.82–0.93). Stroke risk was markedly higher nearly threefold at 30 days and remained elevated throughout follow-up (HRs 1.33–1.87). Recurrent MI risk was approximately 30% higher, and bleeding risk increased with an HR of 1.55 (1.13–2.14) at 30 days. All-cause readmissions were consistently more frequent in the new-onset AF group.
Conclusions
New-onset AF during ACS is associated with substantially higher short-term mortality and persistently elevated stroke risk, recurrent MI, bleeding, and hospital readmission. These patients represent a high-risk group, requiring close monitoring and optimized long term management.