Clinical and Echocardiographic Predictors of New-Onset Atrial Fibrillation in Patients with Non-AF Arrhythmias: An Exploratory Analysis of NT-proBNP

Background/Objectives: Atrial fibrillation (AF) is a prevalent arrhythmia associated with severe clinical complications. This exploratory study aimed to evaluate the prognostic value of clinical characteristics, echocardiographic parameters, and N-terminal pro-B-type natriuretic peptide (NT-proBNP) in predicting new-onset AF among patients previously diagnosed with non-AF arrhythmias. Methods: A prospective cohort study was conducted involving 232 patients who were followed for a median period of 12 months. Data collection included baseline NT-proBNP levels, demographic characteristics, medical history, presenting clinical symptoms, and various paraclinical indices, including echocardiographic measurements. Results: The most frequent presenting symptoms in the study population were syncope (59.9%) and dizziness (55.6%). Statistical analysis indicated that initial NT-proBNP levels were not a significant predictor for the development of new-onset AF (HR = 0.9995; p = 0.717). Conversely, left atrial (LA) size, a history of diabetes mellitus, and a history of stroke were identified as preliminary risk factors requiring confirmation. Specifically, a history of stroke was associated with a nearly 5-fold increase in AF risk (HR = 4.65), while diabetes mellitus increased the risk nearly 4-fold (HR = 3.84). Furthermore, each one-millimeter increase in LA size was associated with a 21% increase in the risk of developing AF (HR = 1.21). Conclusions: The findings suggest that NT-proBNP is not an effective prognostic marker for new-onset AF in patients with non-AF arrhythmias. Instead, left atrial enlargement and clinical comorbidities, such as diabetes and a history of stroke, emerged as suggestive, hypothesis-generating predictors for clinical screening and risk management in this patient population.