Abstract 4363659: Implementing a Mediterranean Diet App in Patients with Atrial Fibrillation: A Pilot Study

Background: Atrial fibrillation (AF) is a common arrhythmia associated with inflammation, symptom burden, and impaired quality of life (QoL). The Mediterranean diet may reduce inflammation and improve cardiometabolic outcomes, yet its effects in AF remain understudied. Mobile health tools offer opportunities to promote dietary change, but few target diet among AF patients. Objective: To evaluate the feasibility and preliminary effects of a self-monitoring Mediterranean diet app (Olitor) on inflammation, symptoms, and QoL in patients with symptomatic AF. Methods: A single-arm pre-post pilot study was conducted over 3 months. Participants (N=14 enrolled; n=10 completed) with symptomatic paroxysmal AF received weekly prompts via the Olitor app to self-report diet adherence and received tailored feedback. Primary outcomes were feasibility (retention), inflammatory markers (CRP, IL-6), AF symptom burden (AF Severity Scale), and QoL (Ferrans and Powers Index). Secondary outcomes included physical activity (IPAQ), diet knowledge, self-efficacy, and BMI. Paired t-tests and non-parametric tests assessed pre-post differences, and effect sizes were calculated. Results: Retention was 83%. Participants were mostly older (M=70.9 years, SD = 9.6), female (60%), and well-educated. IL-6 decreased (median 3.60→3.20 pg/mL, r=−0.43); CRP declined slightly (median 0.14→0.12 mg/L, r = −0.13), though a sensitivity analysis excluding an outlier suggested a moderate effect (r = −0.38). AF severity was stable. QoL improved modestly (M=24.74→25.60, g=0.39); the family QoL subdomain showed significant improvement (p=0.02, g=0.86). BMI decreased significantly (M=26.95→26.46, p=0.03, g=−0.77). Self-efficacy and Mediterranean diet knowledge increased. Walking activity demonstrated a large effect size (g = 0.52). Conclusion: This pilot supports the feasibility and potential benefits of a digital Mediterranean diet intervention in AF. Improvements in inflammation, BMI, and QoL suggest promise for dietary self-monitoring. A larger, controlled trial is warranted to confirm findings and explore long-term effects.