Increased plasma homocysteine predicts arrhythmia recurrence after minimally invasive epicardial ablation for nonvalvular atrial fibrillation

OBJECTIVE: Minimally invasive epicardial ablation via right minithoracotomy is an emerging option for patients with drug-refractory nonvalvular atrial fibrillation. To guide the development of rational treatment algorithms, factors predisposing to recurrence of arrhythmia need to be quantified and eventually treated. We addressed the association of the plasma levels of homocysteine and the recurrence of atrial fibrillation after minimally invasive ablation. METHODS: We obtained peripheral blood samples from 104 patients at follow-up after arrhythmia surgery; the homocysteine concentration was expressed as micromoles per liter. Prospective follow-up was conducted through electrocardiogram Holter monitoring (average 18.5 ± 5.8 months). Stratified analysis (high vs low homocysteine) was based on the cutoff value for the last quartile of homocysteine concentration (16 μmol/L). Time-to-event and diagnostic performance analyses were performed. RESULTS: The rate of freedom from atrial fibrillation was 89.4% at the end of follow-up. Elevated circulating homocysteine level, persistent type of atrial fibrillation, and increased left atrial dimension independently predicted the recurrence of atrial fibrillation during the follow-up (adjusted Cox regression). Patients with a high homocysteine level were more likely to have atrial fibrillation recurrence (stratified Kaplan-Meier, P < .001). The cutoff value for elevated homocysteine (16 μmol/L) yielded a good diagnostic performance in the prediction of atrial fibrillation recurrence (area under the receiver operating characteristic curve, 0.807). CONCLUSIONS: The homocysteine level measured during the follow-up reliably predicts the risk of recurrence after epicardial ablation of nonvalvular atrial fibrillation via minithoracotomy. Specific treatments to reduce plasma homocysteine could be considered in the future in these patients.