Abstract
Summary: A review of 22 patients with atrial fibrillation after the treatment of thyrotoxicosis, who underwent elective electrical cardioversion, showed that only 45% were still in sinus rhythm at 2 years and 36% in the long term (mean 7·4 years). There were no significant differences in factors assessed between those persisting in sinus rhythm and in those who relapsed. A delay in the initial curative treatment of thyrotoxicosis may be a factor in influencing the outcome.