AUTHOR=Li Rui-bin , Yang Xiao-hong , Zhang Ji-dong , Wang Dong , Cui Xiao-ran , Bai Long , Zhao Lei , Cui Wei 

TITLE=The Association Between Subclinical Thyroid Dysfunction and Recurrence of Atrial Fibrillation After Catheter Ablation

JOURNAL=Frontiers in Cardiovascular Medicine

VOLUME=Volume 9 - 2022

YEAR=2022

URL=https://www.frontiersin.org/journals/cardiovascular-medicine/articles/10.3389/fcvm.2022.902411

DOI=10.3389/fcvm.2022.902411

ISSN=2297-055X

ABSTRACT=Objective:To evaluate the association between subclinical thyroid dysfunction and recurrence of atrial fibrillation (AF) after radiofrequency catheter ablation (RFCA). Methods:We examined the association between subclinical thyroid dysfunction and recurrence of AF at a large university affiliated cardiac arrhythmia center in China. Data were obtained regarding consecutive patients underwent RFCA for AF, excluding those who had previous history of hypothyroidism, hyperthyroidism or ongoing medical treatment for hypothyroidism or hyperthyroidism, biochemically defined overt thyroid disease and long-term use of amiodarone prior to admission. The primary endpoint was recurrence of AF in a time-to-event analysis.  We compared outcomes in patients who were with subclinical hyperthyroidism or subclinical hypothyroidism with patients of euthyroid state, using a multivariable Cox model with inverse probability weighting and propensity score matching.
Results: In all, 93 patients were excluded from 435 consecutive patients underwent RFCA for AF. Of the remaining 342 patients for the analysis, the prevalence of subclinical hyperthyroidism and subclinical hypothyroidism were 26(7.6%) and 41(12.0%), respectively; during a median follow-up of 489 days, 91 patients (26.6%) developed a primary endpoint event. In the main analysis of the multivariable Cox model, only subclinical hyperthyroidism (hazard ratio: 3.07, 95% confidence interval: 1.54–6.14) was associated with increased risk of endpoint event after adjusting for potential confounders. However, the association between subclinical hypothyroidism and endpoint event was not significant (hazard ratio: 0.66, 95% confidence interval: 0.31–1.43). Results were consistent either in multiple sensitivity analyses or all subgroups analysis. Compared with individuals with free triiodothyronine (fT3) in the lowest quintile, those with fT3 in the highest quintile had a HR of 2.23 (95% confidence interval, 1.16-4.28) for recurrence of AF. With the increase of thyroid stimulating hormone (TSH), a reduction of risk of recurrence of AF was detected in the adjusted model, and the hazard ratio (HR) per standard deviation (SD) increase was 0.82 (95% confidence interval, 0.68-0.98). Conclusions:In this retrospective cohort study involving patients underwent RFCA for AF, patients with subclinical hyperthyroidism were associated with a markedly higher prevalence of recurrence of AF, whereas patients with subclinical hypothyroidism had a similar recurrence rate of AF compared to those with euthyroid state.