Urinary isoxanthopterin as a novel predictor following catheter ablation for atrial fibrillation

BACKGROUND: Oxidative stress is associated with atrial fibrillation recurrence following catheter ablation. Urinary isoxanthopterin (U‐IXP) is one of the noninvasive markers which reflect the reactive oxygen species; however, its ability to predict atrial tachyarrhythmias (ATAs) occurrence following catheter ablation remains uncertain. METHODS: Among the patients who received scheduled catheter ablation for atrial fibrillation, baseline U‐IXP levels were measured just before the procedure. The prognostic impact of baseline U‐IXP upon postprocedural ATAs occurrence was investigated. RESULTS: Among 107 patients (71 years old, 68% men), baseline U‐IXP level was 0.33 nmol/gCr on the median. During a mean of 603 days of follow‐up, 32 patients had ATAs. Baseline higher U‐IXP was independently associated with the occurrence of ATAs following catheter ablation with a hazard ratio of 4.69 (95% confidence interval: 1.82–12.37, p = .001) adjusted for the left atrial diameter, a persistent type, and hypertension which were potential confounders, with a cutoff of 0.46 nmol/gCr, which stratified cumulative incidence of ATAs occurrence ( p < .001). CONCLUSION: U‐IXP can be used as the noninvasive predictive biomarker for ATAs following catheter ablation for atrial fibrillation.