Patients in the highest quartile of normal free thyroxine levels had a significantly increased risk of atrial fibrillation recurrence after catheter ablation compared to the lowest quartile (HR 3.31).
Cohort (n=244)
No
Does a high-normal level of FT4 increase the risk of AF recurrence after catheter ablation in euthyroid patients with paroxysmal AF?
High-normal thyroid function (FT4) is an independent predictor of atrial fibrillation recurrence following catheter ablation in euthyroid patients.
Hazard Ratio: 3.31 (95% CI 1.45–7.54)
Absolute Event Rate: 38.7% vs 14.8%
p-value: p=0.004
BACKGROUND: It has been shown that the concentration of serum free thyroxine (FT(4)) is independently associated with atrial fibrillation (AF), even in euthyroid persons. This study investigated the effect of a high-normal level of FT(4) on recurrence after catheter ablation of AF. METHODS AND RESULTS: The 244 consecutive patients with paroxysmal AF and who underwent circumferential pulmonary vein isolation (PVI) were prospectively enrolled. Exclusion criteria included prior or current thyroid dysfunction on admission, amiodarone medication for 3 months before admission. After a mean follow-up of 416+/-204 (91-856) days, the recurrence rates were 14.8%, 23.0%, 33.3%, 38.7% from the lowest FT(4) quartile to the highest FT(4) quartile, respectively (P=0.016). After adjustment for age, sex, left atrial diameter, and PVI, there was an increased risk of recurrence in the subjects with the highest FT(4) quartile compared with those with the lowest quartile (hazard ratio 3.31, 95% confidence interval 1.45-7.54, P=0.004). As a continuous variable, FT(4) was also an independent predictor of recurrence (hazard ratio 1.10, 95% confidence interval 1.02-1.18, P=0.016). CONCLUSIONS: Patients with high-normal thyroid function were at an increased risk of AF recurrence after catheter ablation.
Tang et al. (Fri,) conducted a cohort in Paroxysmal atrial fibrillation (n=244). High-normal free thyroxine (FT4) level (highest quartile) vs. Lowest free thyroxine (FT4) quartile was evaluated on Recurrence of atrial fibrillation (HR 3.31, 95% CI 1.45-7.54, p=0.004). Patients in the highest quartile of normal free thyroxine levels had a significantly increased risk of atrial fibrillation recurrence after catheter ablation compared to the lowest quartile (HR 3.31).