Identification, multimodal characterization, and clinical outcomes of pre-atrial fibrillation subclasses

A pre-atrial fibrillation (Pre-AF) status has been postulated to exist when there are structural or electrical findings predisposing to AF, but it is not well-described in relation to prognosis.

This prospective cohort study aims to subclassify Pre-AF by structural, electrical, and biomarker parameters and quantify associations with major adverse events.

Prospective cohort study of individuals with high risk of developing AF (according to the Future Innovation in Novel Detection of Atrial Fibrillation [FIND-AF] risk score), who underwent echocardiographic, electrocardiogram (ECG), and biomarker assessment. Pre-AF subclasses were specified as follows: Pre-AF 1 (1 of echocardiographic, ECG, or biomarker parameters); Pre-AF 2 (2 parameters); and Pre-AF 3 (3 parameters). Individuals were followed up for a composite primary outcome of major adverse cardiovascular, cerebrovascular, and cognitive events (incident AF, heart failure, ischemic stroke/transient ischemic attack, myocardial infarction, dementia, or cardiovascular death).

Of 254 participants (mean age 74.9 [±5.8] years, 50% women), 82 (32.3%) were classified as Pre-AF 1, 90 (35.4%) as Pre-AF 2, and 82 (32.3%) as Pre-AF 3. Higher Pre-AF subclass was associated with higher N-terminal pro-B-type natriuretic peptide (84.0 ng/L vs 186.1 ng/L vs 558.2 ng/L, P < .001) and larger left atrial volume (29.0 mL/m² vs 39.8 mL/m² vs 46.1 mL/m², P < .001). Over a median follow-up of 24.4 months (interquartile range 19.6-26.3 months), the primary outcome was 23.2% (19/82) for Pre-AF 3, 11.1% (10/90) for Pre-AF 2, and 4.9% (4/82) for Pre-AF 1 (log-rank P = .002).

Subclassification of Pre-AF using ECG, echocardiography, and N-terminal pro-B-type natriuretic peptide has prognostic implications but is not specifically associated with diagnosis of incident AF in routine care.