Patients who had hypothyroidism or increased levels of thyroid-stimulating hormone (TSH) were more likely to experience atrial tachyarrhythmia after radiofrequency catheter ablation for atrial fibrillation (AF), according to the results of a study published in the Journal of the American Heart Association.
Clinical parameters of first time patients (n=477) undergoing radiofrequency catheter ablation for AF were recorded and evaluated for possible associations with atrial tachyarrhythmia during a 3-year follow-up period.
Of the 477 patients, 456 had TSH above the lower limit of the normal range (normal TSH group), and 23 had hyperthyroidism. The hypothyroidism group showed significantly lower atrial tachyarrhythmia-free survival than the normal TSH group. When participants were ranked according to their TSH levels, the patients with the highest quartile of TSH had the highest chance of atrial tachyarrhythmia recurrence after the first session.
A high-normal TSH level was the only significant factor that influenced recurrence of atrial tachyarrhythmia after adjusting hazard ratios (HR) in multivariate analysis (adjusted HR, 1.51; 95% CI, 1.07-2.13; P =.018).
In addition, the differences in event-free survivals appeared to be more pronounced in patients with paroxysmal AF vs nonparoxysmal AF after the first and last sessions (first session crude HR, 1.77; 95% CI, 1.14-2.73; P =.010 and last session crude HR, 4.16; 95% CI, 1.86-9.29; P <.001).
The study investigators wrote, “[T]he patients diagnosed with overt and subclinical hypothyroidism had a significantly higher prevalence of atrial tachyarrhythmia recurrence than those with normal TSH after ablation procedures.” They added, “These findings indicate that patients with a successful AF catheter ablation procedure could be exposed to a greater risk of AF recurrence if their TSH level was even on the high end of the normal range, even more so if they had subclinical or overt hypothyroidism.”
Morishima I, Okumura K, Morita Y, et al. High-normal thyroid-stimulating hormone shows a potential causal association with arrhythmia recurrence after catheter ablation of atrial fibrillation [published online July 12, 2018]. J Am Heart Assoc. doi:10.1161/JAHA.118.009158