High-normal thyroid function and risk of recurrence of atrial fibrillation after catheter ablation.
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.


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
Ri-Bo
RB
Department of Cardiology, Beijing An Zhen Hospital, Capital Medical University, Beijing Institute of Heart Lung and Blood Vessel Diseases, Beijing, China.
Liu
Dong-Ling
DL
Dong
Jian-Zeng
JZ
Liu
Xing-Peng
XP
Long
De-Yong
DY
Yu
Rong-Hui
RH
Hu
Fu-Li
FL
Wu
Jia-Hui
JH
Liu
Xiao-Hui
XH
Ma
Chang-Sheng
CS
D000328:Adult; D000368:Aged; D001281:Atrial Fibrillation / Q000209:etiology* / Q000473:pathology; D017115:Catheter Ablation / Q000009:adverse effects*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D019370:Observation; D011237:Predictive Value of Tests; D011446:Prospective Studies; D011667:Pulmonary Veins; D012008:Recurrence; D012306:Risk; D013961:Thyroid Gland / Q000502:physiology*; D013974:Thyroxine / Q000031:analogs & derivatives* / Q000097:blood
C045736:thyroxine sulfate; D013974:Thyroxine