Atrial fibrillation in the young: clinical characteristics, predictors of new onset and outcomes

Introduction: Atrial fibrillation (AF) onset in the young (≤45 years) is uncommon and not well studied. The purpose of this study is to identifying the determinants of AF in this population in order to help direct timely diagnosis, appropriate follow up and management.

Materials and methods: We retrospectively evaluated all patients aged ≤45, admitted to the internal and cardiology wards between January 2009 and December 2019 at a large tertiary center. Clinical, electrocardiographic and echocardiographic data were collected and compared among patients with and without AF at baseline. A subgroup of patients with no AF at baseline and a subsequent hospital visit were followed for development of new onset AF (NOAF).

Results: A total of 16,432 patients (55.5% male, 33 ±8.3 years old) were analyzed. At baseline, patients with AF (n=366) tended to be older, more often male, and had a higher proportion of comorbidities and ECG conduction disorders, compared with the patients without AF (n=16,066). Male sex, increased age, obesity, heart failure (HF) and the presence of left or right bundle branch block (LBBB and RBBB, respectively) were all strongly and independently associated with young-onset AF. A total of 10,691 patients were followed for a median of 41.5 (16.6-78.6) months, during which 85 patients developed NOAF (equivalent to 0.5%/year). Increased age, hypertension, HF, RBBB and LBBB were independent predictors of NOAF. CHARGE-AF score outperformed CHA2DS2-VASc score in NOAF prediction [AUC of ROC 0.75 (0.7-0.8) vs. 0.56 (0.48-0.65)].

Conclusions: The annual risk of NOAF among young adults admitted to the hospital is noteworthy. NOAF may be predicted by clinical risk factors and the CHARGE-AF score