High-Normal Thyroid Function and Risk of Recurrence of Atrial Fibrillation After Catheter Ablation

Abstract

Circulation Journal Official Journal of the Japanese Circulation Society http://www. j-circ.or.jp hyroid dysfunction, especially hyperthyroidism, is frequently associated with the development of atrial fibrillation (AF) and the prevalence of AF in patients with hyperthyroidism is significantly higher than that in euthyroid subjects. 1-3 A previous study reported that the incidence of AF was 2.3% in patients with normal levels of serum thyroid-stimulating hormone (TSH), but increased to 13.8% in patients with hyperthyroidism. 1 Even in patients with subclinical hyperthyroidism, a 5-fold increase in the risk of AF was observed. 1 According to the recent guideline, restoring to euthyroid and rate control were recommended for patients with hyperthyroidism-related AF. 4 In our previous study of patients with hyperthyroidism-related AF who had been euthyroid for more than 3 months, catheter ablation of AF guided by a 3-D mapping system was a therapeutic option. 5 However, the impact of thyroid function on the recurrence rate was not determined according to thyroid function stratification was a limitation of the study. A crosssectional population-based study showed that the serum free thyroxine (FT4) concentration was independently associated with AF, even in euthyroid persons with TSH levels in the normal range. 3 Because most of the AF pathogenic factors present in patients with high levels of FT4 remain even after ablation, it is reasonable to hypothesize that FT4 at a highnormal level increases the risk of recurrence of AF after catheter ablation, so we conducted a prospective study to test this hypothesis. Methods Study SubjectsConsecutive patients with refractory symptomatic paroxysmal AF who were hospitalized in Beijing An Zhen Hospital (affiliated to Capital Medical University) for index circumferential pulmonary vein (PV) radiofrequency ablation from January 2006 to November 2007 were prospectively enrolled. Exclusion criteria included thyroid dysfunction on admission (abnormal level of FT4 or TSH), prior thyroid dysfunc-

Which are the most reliable predictors of recurrence of atrial fibrillation after transcatheter ablation?: a meta-analysis

“…From the 3475 citations first screened, 27 complete reports were evaluated for inclusion in the present research and finally 19 studies were included in the review [14], [15], [16], [17], [18], [19], [20], [21], [22], [23], [24], [25], [26], [27], [28], [29], [30], [31], [32] and [33] (Fig. 1).…”

Prolonged PR Interval and Risk of Recurrence of Atrial Fibrillation After Catheter Ablation

“…Previous studies have examined some predictors of AF recurrence. 6,7) However, there is little information available about the impact of a prolonged PR interval on recurrence of AF after catheter ablation. In patients with a prolonged PR interval, most of the pathogenic factors for AF persist after ablation.…”

History of hyperthyroidism and long-term outcome of catheter ablation of drug-refractory atrial fibrillation

“…12 Similarly, another study showed that patient with high-normal thyroid function was associated with an increased risk of AF recurrence after catheter ablation. 13 Nevertheless, none of these studies have thoroughly examined the presence of PVs and non-PV ectopic foci in patients with history of hyperthyroidism undergoing AF ablation. In the present study, we demonstrated higher prevalence of PVs and non-PVs ectopic foci in patients with hyperthyroidism, which may explain the higher recurrence rate after single procedure.…”

“…This was much higher than the reported range of 1-3% in published studies from China, Sweden, New Zealand and Canada. [34][35][36][37] The possible explanation for the difference 13 could be the frequent referral of complex AF cases with concurrent thyroid disease to our center.…”

“…Previous small studies have reported conflicting results in the outcome of AF ablation in patients with hyperthyroidism. [10][11][12][13] Therefore, we compared the outcome of catheter ablation between euthyroid AF patients with history of hyperthyroidism and normal thyroid AF patients. The electrophysiological characteristics of PVs and atria were compared between the two groups.…”