Long-term impact of the burden of new-onset atrial fibrillation in patients with acute myocardial infarction: data from the NOAFCAMI-SH registry

Abstract Background The prognostic implication of the burden of paroxysmal new-onset atrial fibrillation (NOAF) in patients with acute myocardial infarction (AMI) remains unclear. We aimed to determine the impact of NOAF burden on long-term cardiovascular outcomes in the setting of AMI. Methods This retrospective study was conducted to investigate the association of NOAF burden with the major adverse cardiac events (MACE, a composite of cardiovascular death, recurrent MI, worsening of heart failure, or ischemic stroke), using data from the New Onset Atrial Fibrillation Complicating Acute Myocardial Infarction in ShangHai registry. AF burden was defined as the percentage of time (%) spent in AF. Patients with paroxysmal NOAF were divided into three groups according to AF burden tertiles: low burden: 22.4%. A restricted cubic spline analysis was performed to illusrate the relationship between the burden of NOAF and MACE. Results Of 2399 participants, 278 developed NOAF during a median monitoring period of 194.9 hours. The mean age was 65.8±12.4 years, and the median burden of NOAF was 8.4% (IQR: 1.9%-38.1%). During up to 5-years follow-up, the incidence of MACE was 8.6, 17.4, 35.4, and 79.2 per 100 person-years in the sinus rhythm, low-, intermediate-, and high-burden groups, respectively. After adjustment, patients with high NOAF burden had the highest risk of MACE (hazard ratio [HR]: 3.10; 95% confidence interval [CI]: 2.36–4.07), cardiovascular death (HR: 2.26; 95% CI: 1.58–2.23), worsening of heart failure (HR: 4.90; 95% CI: 3.48–4.91), and ischemic stroke (HR: 4.42; 95% CI: 2.03–9.63). Our splines analyses uncovered a nonlinear dose-response pattern, as the HRs of MACEs increased with the progression of NOAF burden and appeared stable after approximately 15% of NOAF burden. Conclusions A greater burden of NOAF during AMI was strongly associated with a higher risk of adverse cardiovascular events. Multivariable analysis for MACE Clinical outcomes Sinus rhythm Low burden Intermediate burden High burden (n=2121) (n=93) (n=93) (n=92) MACE Events/Incidence (100-person/years) 417 (8.6) 33 (17.4) 45 (35.4) 73 (79.2) Unadjusted HR 1.00 (ref) 1.92 (1.35–2.74) 3.25 (2.39–4.43) 6.55 (5.09–8.41) Adjusted HR* 1.00 (ref) 1.05 (0.72–1.51) 1.66 (1.20–2.30) 3.10 (2.36–4.07) *Adjusted for age, sex, current smoking, hypertension, diabetes, chronic kidney disease, previous heart failure, previous MI, previous stroke/TIA, admission heart failure (Killip >I on arrival), h