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Risk of ischemic stroke after new-onset atrial fibrillation in patients with hyperthyroidism

Chung-Wah Siu1, Vincent Pong, Xuehua Zhang

  • 1Cardiology Division, Department of Medicine, Queen Mary Hospital, the University of Hong Kong, Hong Kong SAR, China.

Heart Rhythm
|February 4, 2009
PubMed

Insights

Hyperthyroidism-induced atrial fibrillation (AF) increases ischemic stroke risk, especially early after diagnosis. Early anticoagulation therapy is crucial for these patients.

Area of Science:

  • Cardiology
  • Endocrinology
  • Neurology

Background:

  • Hyperthyroidism is a common, reversible cause of atrial fibrillation (AF).
  • The specific risk of ischemic stroke in new-onset AF associated with hyperthyroidism remains unclear.
  • Understanding this risk is critical for patient management.

Purpose of the Study:

  • To investigate the clinical outcomes, focusing on ischemic stroke risk.
  • To compare hyperthyroidism-induced AF with non-thyroid AF and hyperthyroid patients without AF.
  • To identify predictors of ischemic stroke in this population.

Main Methods:

  • Prospective study of 160 patients with hyperthyroidism-induced AF.
  • Comparison with age- and sex-matched cohorts: 160 hyperthyroid patients without AF and 160 AF patients without hyperthyroidism.
  • Analysis of incidence, time course, and predictors of ischemic stroke over 1 year.

Main Results:

  • Ischemic stroke occurred in 9.4% of hyperthyroid AF patients vs. 3.1% of non-thyroid AF patients (P = .02).
  • Over 70% of strokes in AF patients occurred within 30 days of presentation.
  • Hyperthyroidism (HR: 3.5) and persistent AF (HR: 13.0) predicted stroke; warfarin reduced risk (HR: 0.17).

Conclusions:

  • Patients with new-onset AF due to hyperthyroidism face an elevated ischemic stroke risk.
  • This risk is concentrated in the initial presentation period.
  • Prompt initiation of anticoagulation therapy is recommended for hyperthyroid patients with AF.
Abstract

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