Predictors of Atrial Fibrillation Recurrence in Hyperthyroid and Euthyroid Patients

Background

Atrial fibrillation (AF) is the most common arrhythmia in adults, and isencountered in 10-15% of the patients with hyperthyroidism. Unlesseuthyroidism is restored, pharmacological or electrical cardioversion iscontroversial in patients with AF who remain hyperthyroid.

Objective

The aim of this study was to assess the efficacy of electrical cardioversionand predictors of AF recurrence in hyperthyroid and euthyroid patients.

Methods

The study included 33 hyperthyroid (21 males) and 48 euthyroid (17 males)patients with persistent AF. The patients were sedated with intravenousmidazolam before undergoing electrical cardioversion delivered bysynchronized biphasic shocks. Rates of AF recurrence were recorded.

Results

Mean follow-up was 23.63 ± 3.74 months in the hyperthyroid group and22.78 ± 3.15 months in the euthyroid group (p = 0.51). AF recurred in14 (43.8%) and 21 (44.7%) patients in each group, respectively (p = 0.93).Multivariate regression analysis in each group showed that AF duration wasthe only predictor of AF recurrence, with odds ratios of 1.38 (95%confidence interval [CI] = 1.05 - 1.82, p = 0.02) in the hyperthyroid groupand 1.42 (95% CI = 1.05 - 1.91, p= 0.02) in the euthyroid group.

Conclusion

Rates of long-term AF recurrence were similar in successfully cardiovertedhyperthyroid and euthyroid patients. The only predictor of AF recurrence inboth groups was AF duration.