RESUMEN
Objective To investigate the effect of thyroxine replacement therapy with residual subclinical hypothyroidism on the success rate of catheter ablation in elderly patients with atrial fibrillation(AF).Methods Among the consecutive patients with AF who underwent a first AF ablation in our center between 2009 and 2012,we identified 56 patients(41 paroxysmal AF,15 persistent AF)with subclinical clinical hypothyroidism after receiving thyroid hormone replacement therapy as study group.The control group consisted of 56 patients with euthyroidism and no history of thyroid dysfunction.All patients underwent catheter ablation.Results At the end of follow up,37.5%(21/56)patients were AF free after the first procedure in the study group,in comparison to 64.3%(36/56)in control group(χ2=8.655,P=0.003).Last procedure was performed in 27 patients of study group and in 15 patients of control group.After the last performed ablation,62.5%(35/56)study group patients and 80.4%(45/56)controls group patients had no recurrence(χ2=4.653,P=0.031).The major complications rate did not differ between two groups(P=0.642).Conclusions Thyroid hormone replacement therapy with residual subclinical hypothyroidism reduces catheter ablation success rate in elderly patients with atrial fibrillation.