SUBCLINICAL HYPERTHYROIDISM AND OVERT HYPERTHYROIDISM AS A RISK FACTORS FOR ATRIAL FIBRILLATION IN AL- NASIRIYAH CITY

Abstract

Background  Atrial fibrillation is a well known manifestation of hyperthyroidism , we studied whether subclinical hyperthyroidism in clinically euothyroid persons is a risk factor for  atrial fibrillation .  Method we studied 267  persons  , the subject was classified into 3  groups according to the serum TSH  group I:   ( 174 ) persons compromised those with normal values of serum TSH  ( 0.25 – 5 μU/ml) and T3 , T4  within normal limit , this group  considered as control group. group II:  ( 61 ) persons those  with low serum  TSH ( < 0.25 μU/ml)   and with elevated serum T3 and T4  i.e  overt hyperthyroidism. group III:   ( 32 ) persons those  with low serum TSH  ( < 0.25 μU/ml )   and T3 and T4 within normal limit  i. e. sub clinical hyperthyroidism . Result:  Atrial fibrillation ( AF )  was presented in 4 only from 174 with a percent of ( 2.3 %) in group I  ,but  9 only from 61 persons with a percent of ( 13.8 %) were presented in group II ,  while 4  only from 32 persons with a percent of  ( 12.7 %) in group III . There is significant difference ( P < 0.01 ) between group I when it compared with other groups . Conclusion:  Low serum thyrotropin concentration is associated with more than 5 fold higher likely hood for the presence of AF with no significance difference between subclinical and overt hyperthyroidism .