Atrial fibrillation affects millions of adults worldwide, and its rising prevalence tracks closely with the global obesity epidemic — yet most clinical management still defaults to pharmacology and ablation. A growing body of evidence reframes AF not merely as an electrical disorder but as a downstream consequence of cardiometabolic dysfunction, opening the door for lifestyle-based upstream intervention. Understanding whether combined diet-plus-exercise programs can meaningfully reduce AF burden would shift how clinicians counsel overweight patients.
This registered systematic review protocol, published in BMJ Open, outlines a methodologically rigorous search across MEDLINE, CINAHL, EMBASE, and EMCARE from database inception through April 2026. The review will restrict eligibility to randomized controlled trials, quasi-experimental studies, and controlled cohort studies involving adults with confirmed AF who are overweight or obese. The distinguishing feature is the dual-component requirement: studies examining only diet or only exercise in isolation will be excluded. Primary outcome is AF symptom burden quantified via validated instruments; secondary outcomes include quality of life, anthropometric measures, metabolic parameters, and arrhythmia burden. Risk of bias will be assessed using RoB 2 for randomized trials and an appropriate tool for non-randomized designs.
This protocol addresses a genuine gap. Several trials — most notably the LEGACY and CARDIO-FIT studies — demonstrated that weight loss magnitude and cardiorespiratory fitness gains independently predict AF recurrence reduction. However, whether combining structured dietary intervention with exercise amplifies these benefits beyond either alone remains unanswered at the systematic review level. The cardiometabolic mechanisms are plausible: adipose-driven atrial fibrosis, inflammatory cytokines, and vagal remodeling may all respond to concurrent metabolic and fitness improvements. The key limitation at this stage is that no data have yet been synthesized — this is a protocol only, meaning actual findings remain pending. If the eventual review surfaces sufficient homogeneous trials, it could meaningfully inform cardiac rehabilitation program design for AF patients. Currently, this represents promising groundwork rather than actionable evidence.