The effect of antithyroid treatment on atrial conduction times in patients with subclinical hyperthyroidism.
BACKGROUND
Prolonged atrial conduction time measured by tissue Doppler imaging (TDI) has been associated with increased risk of atrial fibrillation. We aimed to evaluate the effect of subclinical hyperthyroidism (SH) and antithyroid treatment on atrial conduction time.


METHODS
A total of 30 patients with SH (26 females; mean age 34.8 ± 8.5 years) and 30 age- and gender-matched controls were included. Using TDI, atrial conduction time was measured from the lateral mitral annulus, septal mitral annulus, and lateral tricuspid annulus. Intra- and interatrial conduction delay were calculated. TDI and thyroid hormone levels were studied at the time of enrollment and after achievement of euthyroid state with propylthiouracil treatment. Patients were followed for 14 ± 3 weeks.


RESULTS
Atrial conduction time at the lateral and septal mitral annulus were significantly higher in patients with SH compared to controls. Both inter-, right, and left intraatrial electromechanical delay were prolonged in patients with SH compared to control subjects (21.3 ± 6.1 vs. 13.9 ± 4.3, P < 0.001 and 4.2 ± 3.5 vs. 2.3 ± 1.9, P = 0.014 and 17.1 ± 6.0 vs. 11.6 ± 3.8, P < 0.001, respectively). After achievement of euthyroid state, inter- and left intraatrial electromechanical delay were significantly decreased compared to baseline values and approximated to the values of the control group (P < 0.001).


CONCLUSIONS
SH is associated with prolonged atrial conduction time. After achievement of euthyroid state, decrement in atrial conduction time may reveal how the antithyroid treatment may prevent the development of atrial fibrillation in these patients.
Elbistan State Hospital, Kahramanmaraş, Turkey. dralpernacar@hotmail.com
Alper Buğra
AB
Nacar
Gürkan
G
Acar
Hikmet
H
Yorgun
Ahmet
A
Akçay
Mesut
M
Özkaya
Uğur
U
Canpolat
Murat
M
Akkoyun
Cemal
C
Tuncer
D000328:Adult; D013956:Antithyroid Agents / Q000008:administration & dosage*; D005260:Female; D006325:Heart Atria / Q000187:drug effects / Q000503:physiopathology*; D006329:Heart Conduction System / Q000187:drug effects / Q000503:physiopathology*; D006801:Humans; D006980:Hyperthyroidism / Q000188:drug therapy* / Q000503:physiopathology*; D008297:Male; D009431:Neural Conduction / Q000187:drug effects*
D013956:Antithyroid Agents