Atrial fibrillation and hyperthyroidism: relation between transoesophageal markers of a thrombogenic milieu and clinical risk factors for thromboembolism

Summary Hyperthyroidism is a questionable risk factor for thromboembolism among patients with atrial fibrillation. Objective  To correlate clinical risk factors for thromboembolism from a group of patients with atrial fibrillation related to hyperthyroidism with transoesophageal echocardiography (TOE) markers of a thrombogenic milieu. Design  Clinical risk factors for thromboembolism, thyroid hormonal status, time since diagnosis of hyperthyroidism and TOE markers of a thrombogenic milieu were assessed in consecutive patients with atrial fibrillation related to hyperthyroidism. The following TOE parameters were assessed to define the presence of thrombogenic milieu: dense spontaneous echo contrast, thrombi or left atrial appendage blood flow velocities <0·20 m/s. Clinical risk factors for thromboembolism were based on CHADS2 (Cardiac failure, Hypertension, Age, Diabetes and Stroke) classification. Patients  This study included 31 consecutive patients aged between 18 and 65 years with atrial fibrillation related to hyperthyroidism scheduled for TOE. Results  Thrombogenic milieu was present in 14 of 31 (45·2%) patients. The thyroid status could not predict the presence of a thrombogenic milieu. Despite low CHADS2 score of 0/1, 6 of 13 (46·1%) patients had a thrombogenic milieu, whereas 10 of 18 (55·6%) patients with score ≥2 had none. The probability of having a thrombogenic milieu did not correlate with the number of clinical risk factors. Conclusion  Among patients younger than 65 years of age with atrial fibrillation related to hyperthyroidism, there is no association between clinical risk factors with TOE markers of a thrombogenic milieu. TOE adds useful information that may affect antithrombotic therapy guided by clinical risk classification.