Impact of prior hyperthyroidism and thyroid hormone elevations on atrial fibrillation recurrence after catheter ablation: a time-to-event meta-analysis of adjusted data
S Faizollah Zadeh Ardebili, L Seferasi, D Barzetti, G Vianna Rosseto, B Lins De Souza, F Palma-Garcia, K SedlacekAbstract
Background
Hyperthyroidism is well-recognised as a reversible cause of atrial fibrillation (AF). However, whether prior history of hyperthyroidism increases the recurrence of AF after catheter ablation is poorly understood.
Purpose
To determine the prognostic impact of prior hyperthyroidism and elevated thyroid hormone levels within the normal range on AF recurrence post-catheter ablation.
Methods
We systematically searched PubMed, Embase, and Cochrane databases for studies assessing the impact of overt or subclinical hyperthyroidism on the recurrence of AF after catheter ablation. Elevated quartiles of free triiodothyronine (FT3) and free thyroxine (FT4) within the euthyroid range were also meta-analysed as predictors of AF recurrence. Log-hazard ratio (HR) transformations were used to standardise FT3 and FT4 quartiles into a consistent high-versus-reference comparison across studies. To minimize confounding, we pooled adjusted HRs and their 95% confidence intervals (CIs) using a random effects model. Heterogeneity was evaluated using the Cochrane Q test and I² statistics; p values inferior to 0.10 and I² > 25% were deemed significant for heterogeneity.
Results
Ten studies comprising 4,741 patients were included. Previous history of overt or subclinical hyperthyroidism significantly increased the recurrence of AF after catheter ablation (HR 2.00; 95% CI 1.31-3.06; p = 0.0083; I² = 16.9%; Figure 1). In euthyroid patients, high quartiles of FT4 were strongly associated with the recurrence of AF (HR 1.24; 95% CI 1.16-1.32; p = 0019; I² = 0.0%; Figure 2). Despite an observable trend, FT3 elevations were not significantly associated with the recurrence of AF post-ablation (HR 1.40; 95% CI 0.67-2.89; p = 0.1085; I² = 0.0%).
Conclusion
Prior history of hyperthyroidism increases the risk of AF recurrence in patients undergoing catheter ablation, even after restoration of euthyroid status. Thorough assessments of FT4, and potentially FT3, during follow-up may help identify patients at an increased risk of AF recurrence.Figure 1.History of hyperthyroidismFigure 2.Elevated FT4 levels