Baseline apnoea/hypopnoea index and high-sensitivity C-reactive protein for the risk of recurrence of atrial fibrillation after successful electrical cardioversion: a predictive model based upon the multiple effects of significant variables

Aims We tested apnoea/hypopnoea index (AHI), high-sensitivity (hs) C-reactive protein and clinical/instrumental variables as predictors of atrial fibrillation (AF) recurrence over 1-year follow-up after successful electrical cardioversion. Methods and results We enrolled 158 consecutive patients. Apnoea/hypopnoea index was assessed with standard overnight polysomnography and hs-C-reactive protein with immunonephelometry assay the day before electrical cardioversion. Atrial fibrillation recurrences occurred in 81 patients (51%). Predictors at univariate analysis were: AHI ≥ 15 events/h ( P = 0.001), hs-C-reactive protein >0.30 mg/dL ( P = 0.009), AF duration >3 days ( P = 0.008), diabetes ( P = 0.03), and ongoing anti-arrhythmic therapy at the time of electrical cardioversion ( P = 0.03). Survival analysis confirmed that patients with AHI ≥ 15 events/h and hs-C-reactive protein > 0.30 mg/dL had a higher recurrence rate of AF (log rank P = 0.0006 and P = 0.01, respectively). Predictors at multivariate analysis were: AHI ≥ 15 events/h ( P = 0.003), hs-C-reactive protein > 0.30 mg/dL ( P = 0.01) and ongoing anti-arrhythmic therapy ( P = 0.04). A predictive model based upon the multiple effects of significant variables plus age as a continuous variable stratified the risk of AF recurrence, more than tripled with all dichotomized variables altered with respect to normal variables (85 vs. 27%). Conclusion AHI ≥ 15 events/h and hs-C-reactive protein > 0.30 mg/dL are the strongest predictors of the predictors chosen of AF recurrence after successful electrical cardioversion over 1-year follow-up.